Jan’s Publications

@article{WOS:000943729600001,

title = {Puddle formation and persistent gaps across the non-mean-field breakdown 

 of superconductivity in overdoped 

 (Pb,Bi)_{2}Sr_{2}CuO_{6+δ}},

author = {Willem O. Tromp and Tjerk Benschop and Jian-Feng Ge and Irene Battisti and Koen M. Bastiaans and Damianos Chatzopoulos and Amber H. M. Vervloet and Steef Smit and Erik Heumen and Mark S. Golden and Yinkai Huang and Takeshi Kondo and Tsunehiro Takeuchi and Yi Yin and Jennifer E. Hoffman and Miguel Antonio Sulangi and Jan Zaanen and Milan P. Allan},

doi = {10.1038/s41563-023-01497-1},

issn = {1476-1122},

year  = {2023},

date = {2023-06-01},

journal = {NATURE MATERIALS},

volume = {22},

number = {6},

pages = {703+},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {The cuprate high-temperature superconductors exhibit many unexplained 

 electronic phases, but the superconductivity at high doping is often 

 believed to be governed by conventional mean-field 

 Bardeen-Cooper-Schrieffer theory(1). However, it was shown that the 

 superfluid density vanishes when the transition temperature goes to 

 zero(2,3), in contradiction to expectations from 

 Bardeen-Cooper-Schrieffer theory. Our scanning tunnelling spectroscopy 

 measurements in the overdoped regime of the (Pb,Bi)(2)Sr2CuO6+delta 

 high-temperature superconductor show that this is due to the emergence 

 of nanoscale superconducting puddles in a metallic matrix(4,5). Our 

 measurements further reveal that this puddling is driven by gap filling 

 instead of gap closing. The important implication is that it is not a 

 diminishing pairing interaction that causes the breakdown of 

 superconductivity. Unexpectedly, the measured gap-to-filling correlation 

 also reveals that pair breaking by disorder does not play a dominant 

 role and that the mechanism of superconductivity in overdoped cuprate 

 superconductors is qualitatively different from conventional mean-field 

 theory.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000996954400001,

title = {High T_{c} superconductivity in Copper oxides: the condensing 

 bosons as stripy plaquettes},

author = {Jan Zaanen},

doi = {10.1038/s41535-023-00561-y},

year  = {2023},

date = {2023-05-01},

journal = {NPJ QUANTUM MATERIALS},

volume = {8},

number = {1},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {For the first time, the nature of the carriers in strongly underdoped 

 cuprates has been mapped with spin polarized scanning tunneling 

 spectroscopy by a group in Nanjing, revealing that these form mysterious 

 collective entities living on plaquettes of size 4 lattice constants 

 with intriguing internal structure.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000981107600005,

title = {Motion of a superfluid vortex according to holographic quantum 

 dissipation},

author = {Wei -Can Yang and Chuan-Yin Xia and Hua-Bi Zeng and Makoto Tsubota and Jan Zaanen},

doi = {10.1103/PhysRevB.107.144511},

issn = {2469-9950},

year  = {2023},

date = {2023-04-01},

journal = {PHYSICAL REVIEW B},

volume = {107},

number = {14},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {Vortices are topological defects associated with superfluids and 

 superconductors, which, when mobile, dissipate energy destroying the 

 dissipationless nature of the superfluid. The nature of this ``quantum 

 dissipation'' is rooted in the quantum physical nature of the problem, 

 which has been the subject of an extensive literature. However, this has 

 mostly been focused on the measures applicable in weakly interacting 

 systems wherein they are tractable via conventional methods. Recently, 

 it became possible to address such dynamical quantum thermalization 

 problems in very strongly interacting systems using the holographic 

 duality discovered in string theory, mapping the quantum problem on a 

 gravitational problem in one higher dimension, having as benefit 

 offering a more general view on how dissipation emerges from such 

 intricate quantum physical circumstances. We study here the elementary 

 problem of a single vortex in two space dimensions, set in motion by a 

 sudden quench in the background superflow formed in a finite-density 

 Reissner-Nordstrom holographic superfluid. This reveals a number of 

 surprising outcomes addressing questions of principle. By fitting the 

 trajectories unambiguously to the Hall-Vinen-Iordanskii phenomenological 

 equation of motion we find that these are characterized by a large 

 inertial mass at low temperature that, however, diminishes upon raising 

 temperature. For a weak drive the drag is found to increase when 

 temperature is lowered, which reveals a simple shear drag associated 

 with the viscous metallic vortex cores, supplemented by a conventional 

 normal fluid component at higher temperatures. For a strong drive we 

 discover a unique dynamical phenomenon: the core of the vortex deforms 

 accompanied by a large increase of the drag force.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000918192100003,

title = {Identification of a characteristic doping for charge order phenomena in 

 Bi-2212 cuprates via RIXS},

author = {Haiyu Lu and Makoto Hashimoto and Su-Di Chen and Shigeyuki Ishida and Dongjoon Song and Hiroshi Eisaki and Abhishek Nag and Mirian Garcia-Fernandez and Riccardo Arpaia and Giacomo Ghiringhelli and Lucio Braicovich and Jan Zaanen and Brian Moritz and Kurt Kummer and Nicholas B. Brookes and Ke-Jin Zhou and Zhi-Xun Shen and Thomas P. Devereaux and Wei-Sheng Lee},

doi = {10.1103/PhysRevB.106.155109},

issn = {2469-9950},

year  = {2022},

date = {2022-10-01},

journal = {PHYSICAL REVIEW B},

volume = {106},

number = {15},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {Identifying quantum critical points (QCPs) and their associated 

 fluctuations may hold the key to unraveling the unusual electronic 

 phenomena observed in cuprate superconductors. Recently, signatures of 

 quantum fluctuations associated with charge order (CO) have been 

 inferred from the anomalous enhancement of CO excitations that accompany 

 the reduction of the CO order parameter in the superconducting state. To 

 gain more insight into the interplay between CO and superconductivity, 

 here we investigate the doping dependence of this phenomenon throughout 

 the Bi-2212 cuprate phase diagram using resonant inelastic x-ray 

 scattering (RIXS) at the Cu L-3 edge. As doping increases, the CO wave 

 vector decreases, saturating near a commensurate value of 0.25 

 reciprocal lattice unit beyond a characteristic doping p(c), where the 

 correlation length becomes shorter than the apparent periodicity 

 (4a(0)). Such behavior is indicative of the fluctuating nature of the 

 CO; the proliferation of CO excitations in the superconducting state 

 also appears strongest at p(c), consistent with expected behavior at a 

 CO QCP. Intriguingly, p(c) appears to be near optimal doping, where the 

 superconducting transition temperature T-c is maximal.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000862821200001,

title = {Strange metal electrodynamics across the phase diagram of 

 Bi_{2-\textit{x}}Pb\textit{_{x}}Sr_{2-\textit{y}}La\textit{ 

 _{y}}CuO_{6+d}cuprates},

author = {Erik Heumen and Xuanbo Feng and Silvia Cassanelli and Linda Neubrand and Lennart Jager and Maarten Berben and Yingkai Huang and Takeshi Kondo and Tsunehiro Takeuchi and Jan Zaanen},

doi = {10.1103/PhysRevB.106.054515},

issn = {2469-9950},

year  = {2022},

date = {2022-08-01},

journal = {PHYSICAL REVIEW B},

volume = {106},

number = {5},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {Unlocking the mystery of the strange metal state has become the focal 

 point of high-Tcresearch, not because of its importance for 

 superconductivity, but because it appears to represent a truly novel 

 phase of matter dubbed ``quantum supreme matter. `` Detected originally 

 through high magnetic field, transport experiments, signatures of this 

 phase have now been uncovered with a variety of probes. Our high 

 resolution optical data of the low-Tccuprate superconductor, 

 Bi2-xPbxSr2-yLayCuO6+delta allows us to probe this phase over a large 

 energy and temperature window. We demonstrate that the optical 

 signatures of the strange metal phase persist throughout the phase 

 diagram. The strange metal signatures in the optical conductivity are 

 twofold: (i) a low energy Drude response with Drude width on the order 

 of temperature and (ii) a high energy conformal tail with a doping 

 dependent power-law exponent. While the Drude weight evolves 

 monotonically throughout the entire doping range studied, the spectral 

 weight contained in the high energy conformal tail appears to be doping 

 and temperature independent. Our analysis further shows that the 

 temperature dependence of the optical conductivity is completely 

 determined by the Drude parameters. Our results indicate that there is 

 no critical doping level inside the superconducting dome where the 

 carrier density starts to change drastically and that the previously 

 observed ``return to normalcy `` is a consequence of the increasing 

 importance of the Drude component relative to the conformal tail with 

 doping. Importantly, both the doping and temperature dependence of the 

 resistivity are largely determined by the Drude width.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000863121000012,

title = {Crystal gravity},

author = {Jan Zaanen and Floris Balm and Aron J. Beekman},

doi = {10.21468/SciPostPhys.13.2.039},

issn = {2542-4653},

year  = {2022},

date = {2022-08-01},

journal = {SCIPOST PHYSICS},

volume = {13},

number = {2},

publisher = {SCIPOST FOUNDATION},

address = {C/O J S CAUX, INST PHYSICS, UNIV AMSTERDAM, AMSTERDAM, 1098 XH, 

 NETHERLANDS},

abstract = {We address a subject that could have been analyzed century ago: how does 

 the universe of general relativity look like when it would have been 

 filled with solid matter? Solids break spontaneously the translations 

 and rotations of space itself. Only rather recently it was realized in 

 various context that the order parameter of the solid has a relation to 

 Einsteins dynamical space time which is similar to the role of a Higgs 

 field in a Yang-Mills gauge theory. Such a ``crystal gravity'' is 

 therefore like the Higgs phase of gravity. The usual Higgs phases are 

 characterized by a special phenomenology. A case in point is 

 superconductivity exhibiting phenomena like the Type II phase, 

 characterized by the emergence of an Abrikosov lattice of quantized 

 magnetic fluxes absorbing the external magnetic field. What to expect in 

 the gravitational setting? The theory of elasticity is the universal 

 effective field theory associated with the breaking of space 

 translations and rotations having a similar status as the phase action 

 describing a neutral superfluid. A geometrical formulation appeared in 

 its long history, similar in structure to general relativity, which 

 greatly facilitates the marriage of both theories. With as main 

 limita-tion that we focus entirely on stationary circumstances - the 

 dynamical theory is greatly complicated by the lack of Lorentz 

 invariance - we will present a first exploration of a remarkably rich 

 and often simple physics of ``Higgsed gravity''.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000769913500001,

title = {The uncanny valley of a virtual animal},

author = {Alexandra Sierra Rativa and Marie Postma and Menno Zaanen},

doi = {10.1002/cav.2043},

issn = {1546-4261},

year  = {2022},

date = {2022-03-01},

journal = {COMPUTER ANIMATION AND VIRTUAL WORLDS},

volume = {33},

number = {2},

publisher = {WILEY},

address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA},

abstract = {Virtual robots, including virtual animals, are expected to play a major 

 role within affective and aesthetic interfaces, serious games, video 

 instruction, and the personalization of educational instruction. Their 

 actual impact, however, will very much depend on user perception of 

 virtual characters as the uncanny valley hypothesis has shown that the 

 design of virtual characters determines user experiences. In this 

 article, we investigated whether the uncanny valley effect, which has 

 already been found for the human-like appearance of virtual characters, 

 can also be found for animal-like appearances. We conducted an online study (N = 163) in which six different animal designs were evaluated in 

 terms of the following properties: familiarity, commonality, 

 naturalness, attractiveness, interestingness, and animateness. The study 

 participants differed in age (under 10-60 years) and origin (Europe, 

 Asia, North America, and South America). For the evaluation of the 

 results, we ranked the animal-likeness of the character using both 

 expert opinion and participant judgments. Next to that, we investigated 

 the effect of movement and morbidity. The results confirm the existence 

 of the uncanny valley effect for virtual animals, especially with 

 respect to familiarity and commonality, for both still and moving 

 images. The effect was particularly pronounced for morbid images. For 

 naturalness and attractiveness, the effect was only present in the 

 expert-based ranking, but not in the participant-based ranking. No 

 uncanny valley effect was detected for interestingness and animateness. 

 This investigation revealed that the appearance of virtual animals 

 directly affects user perception and thus, presumably, impacts user 

 experience when used in applied settings.},

keywords = {animal-likeness; animateness; attractiveness; commonality; familiarity;   interestingness; naturalness; uncanny valley; virtual animals; virtual   characters; virtual pandas},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000761175600002,

title = {Spin texture in doped Mott insulators with spin-orbit coupling},

author = {Shuai A. Chen and Zheng-Yu Weng and Jan Zaanen},

doi = {10.1103/PhysRevB.105.075136},

issn = {2469-9950},

year  = {2022},

date = {2022-02-01},

journal = {PHYSICAL REVIEW B},

volume = {105},

number = {7},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {A hole injected into a Mott insulator will gain an internal structure as 

 recently identified by exact numerics, which is characterized by a 

 nontrivial quantum number whose nature is of central importance in 

 understanding the Mott physics. In this work, we show that a spin 

 texture associated with such an internal degree of freedom can 

 explicitly manifest after the spin degeneracy is lifted by a weak Rashba 

 spin-orbit coupling (SOC). It is described by an emergent angular momentum J(z) = +/- 3/2 as shown by both exact diagonalization and 

 variational Monte Carlo calculations, which are in good agreement with 

 each other at a finite size. In particular, as the internal structure 

 such a spin texture is generally present in the hole composite even at 

 high excited energies, such that a corresponding texture in momentum 

 space, extending deep inside the Brillouin zone, can be directly probed 

 by the spin-polarized angle-resolved photoemission spectroscopy (ARPES). 

 This is in contrast to a Landau quasiparticle under the SOC, in which 

 the spin texture induced by SOC will not be protected once the excited 

 energy is larger than the weak SOC coupling strength, away from the 

 Fermi energy. We point out that the spin texture due to the SOC should 

 be monotonically enhanced with reducing spin-spin correlation length in 

 the superconducting-pseudogap phase at finite doping. A brief discussion 

 of a recent experiment of the spinpolarized ARPES will be made.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000749546400024,

title = {Unconventional spectral signature of \textit{T}_{c} in a pure 

 \textit{d}-wave superconductor},

author = {Su-Di Chen and Makoto Hashimoto and Yu He and Dongjoon Song and Jun-Feng He and Ying-Fei Li and Shigeyuki Ishida and Hiroshi Eisaki and Jan Zaanen and Thomas P. Devereaux and Dung-Hai Lee and Dong-Hui Lu and Zhi-Xun Shen},

doi = {10.1038/s41586-021-04251-2},

issn = {0028-0836},

year  = {2022},

date = {2022-01-01},

journal = {NATURE},

volume = {601},

number = {7894},

pages = {562+},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {In conventional superconductors, the phase transition into a 

 zero-resistance and perfectly diamagnetic state is accompanied by a jump 

 in the specific heat and the opening of a spectral gap(1). In the 

 high-transition-temperature (high-T-c) cuprates, although the transport, 

 magnetic and thermodynamic signatures of T-c have been known since the 

 1980s(2), the spectroscopic singularity associated with the transition 

 remains unknown. Here we resolve this long-standing puzzle with a 

 high-precision angle-resolved photoemission spectroscopy (ARPES) study 

 on overdoped (Bi,Pb)(2)Sr2CaCu2O8+delta (Bi2212). We first probe the 

 momentum-resolved electronic specific heat via spectroscopy and 

 reproduce the specific heat peak at T-c, completing the missing link for 

 a holistic description of superconductivity. Then, by studying the full 

 momentum, energy and temperature evolution of the spectra, we reveal 

 that this thermodynamic anomaly arises from the singular growth of 

 in-gap spectral intensity across T-c. Furthermore, we observe that the 

 temperature evolution of in-gap intensity is highly anisotropic in the 

 momentum space, and the gap itself obeys both the d-wave functional form 

 and particle-hole symmetry. These findings support the scenario that the 

 superconducting transition is driven by phase fluctuations. They also 

 serve as an anchor point for understanding the Fermi arc and pseudogap 

 phenomena in underdoped cuprates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000740848100002,

title = {Holographic Abrikosov lattice: Vortex matter from black hole},

author = {Chuan-Yin Xia and Hua-Bi Zeng and Yu Tian and Chiang-Mei Chen and Jan Zaanen},

doi = {10.1103/PhysRevD.105.L021901},

issn = {2470-0010},

year  = {2022},

date = {2022-01-01},

journal = {PHYSICAL REVIEW D},

volume = {105},

number = {2},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The AdS/CFT correspondence provides a unique way to study the vortex 

 matter phases in superconductors. We solve the dynamical evolution of a 

 superconductor in 2 thorn 1 dimensions at a finite temperature subjected 

 to a magnetic field quench in terms of a gravitational ``hairy black 

 hole'' dual living in an asymptotic AdS 4 space. We exploit this to 

 determine the nature of the equilibrium states realized at long times 

 after the quench of this two dimensional type II superconductor in a 

 perpendicular external uniform magnetic field B-0. This holographic 

 superconductor exhibits the generic lower (B-c1 (T)) and upper (B-c2 

 (T)) critical fields. For B-0 < B-c1 (T) the magnetic field is 

 completely expelled revealing the Meissner phase, while the 

 superconductivity is destroyed when B-0 > B-c2 (T). Abrikosov lattices 

 appear in the range B-c1(T) < B-0 < B-c2 (T) that realize various 

 configurations in the form of hexagonal, square and slightly irregular 

 square lattices pending the magnetic field strength and the influence of 

 finite size boundaries. We show this to be consistent with the 

 expectations of Ginzburg-Landau theory where the upper and lower 

 critical fields are associated with the inverse squares of the coherence 

 length and magnetic penetration depth, respectively.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000713603000001,

title = {A Product- and Process-Oriented Tagset for Revisions in Writing},

author = {Rianne Conijn and Emily Dux Speltz and Menno van Zaanen and Luuk Van Waes and Evgeny Chukharev-Hudilainen},

doi = {10.1177/07410883211052104},

issn = {0741-0883},

year  = {2022},

date = {2022-01-01},

journal = {WRITTEN COMMUNICATION},

volume = {39},

number = {1},

pages = {97-128},

publisher = {SAGE PUBLICATIONS INC},

address = {2455 TELLER RD, THOUSAND OAKS, CA 91320 USA},

abstract = {The study of revision has been a topic of interest in writing research 

 over the past decades. Numerous studies have, for instance, shown that 

 learning-to-revise is one of the key competences in writing development. 

 Moreover, several models of revision have been developed, and a variety 

 of taxonomies have been used to measure revision in empirical studies. 

 Current advances in data collection and analysis have made it possible 

 to study revision in increasingly precise detail. The present study 

 aimed to combine previous models and current advances by providing a 

 comprehensive product- and process-oriented tagset of revision. The 

 presented tagset includes properties of external revisions: trigger, 

 orientation, evaluation, action, linguistic domain, spatial location, 

 temporal location, duration, and sequencing. We identified how keystroke 

 logging, screen replays, and eye tracking can be used to extract both 

 manually and automatically extract features related to these properties. 

 As a proof of concept, we demonstrate how this tagset can be used to 

 annotate revisions made by higher education students in various academic 

 tasks. To conclude, we discuss how this tagset forms a scalable basis 

 for studying revision in writing in depth.},

keywords = {writing analytics; writing process; revision processes; keystroke   logging; eye tracking; annotation},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000678820500007,

title = {Incoherent transport across the strange-metal regime of overdoped 

 cuprates},

author = {J. Ayres and M. Berben and M. Culo and Y-T Hsu and E. Heumen and Y. Huang and J. Zaanen and T. Kondo and T. Takeuchi and J. R. Cooper and C. Putzke and S. Friedemann and A. Carrington and N. E. Hussey},

doi = {10.1038/s41586-021-03622-z},

issn = {0028-0836},

year  = {2021},

date = {2021-07-01},

journal = {NATURE},

volume = {595},

number = {7869},

pages = {661+},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {Strange metals possess highly unconventional electrical properties, such 

 as a linear-in-temperature resistivity(1-6), an inverse Hall angle that 

 varies as temperature squared(7-9) and a linear-in-field 

 magnetoresistance(10-13). Identifying the origin of these collective 

 anomalies has proved fundamentally challenging, even in materials such 

 as the hole-doped cuprates that possess a simple bandstructure. The 

 prevailing consensus is that strange metallicity in the cuprates is tied 

 to a quantum critical point at a doping p* inside the superconducting 

 dome(14,15). Here we study the high-field in-plane magnetoresistance of 

 two superconducting cuprate families at doping levels beyond p*. At 

 all dopings, the magnetoresistance exhibits quadrature scaling and 

 becomes linear at high values of the ratio of the field and the 

 temperature, indicating that the strange-metal regime extends well 

 beyond p*. Moreover, the magnitude of the magnetoresistance is found 

 to be much larger than predicted by conventional theory and is 

 insensitive to both impurity scattering and magnetic field orientation. 

 These observations, coupled with analysis of the zero-field and Hall 

 resistivities, suggest that despite having a single band, the cuprate 

 strange-metal region hosts two charge sectors, one containing coherent 

 quasiparticles, the other scale-invariant `Planckian' dissipators. 

 Measurements of high-field magnetotransport in overdoped cuprates 

 indicate that the strange-metal regime exists beyond the critical 

 doping, and that it has both coherent and incoherent contributions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000677855400043,

title = {Magnetic excitations in infinite-layer nickelates},

author = {H. Lu and M. Rossi and A. Nag and M. Osada and D. F. Li and K. Lee and B. Y. Wang and M. Garcia-Fernandez and S. Agrestini and Z. X. Shen and E. M. Been and B. Moritz and T. P. Devereaux and J. Zaanen and H. Y. Hwang and Ke-Jin Zhou and W. S. Lee},

doi = {10.1126/science.abd7726},

issn = {0036-8075},

year  = {2021},

date = {2021-07-01},

journal = {SCIENCE},

volume = {373},

number = {6551},

pages = {213+},

publisher = {AMER ASSOC ADVANCEMENT SCIENCE},

address = {1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA},

abstract = {The discovery of superconductivity in infinite-layer nickelates brings 

 us tantalizingly close to a material class that mirrors the cuprate 

 superconductors. We measured the magnetic excitations in these 

 nickelates using resonant inelastic x-ray scattering at the Ni L-3-edge. 

 Undoped NdNiO2 possesses a branch of dispersive excitations with a 

 bandwidth of approximately 200 milli-electron volts, which is 

 reminiscent of the spin wave of strongly coupled, antiferromagnetically 

 aligned spins on a square lattice. The substantial damping of these 

 modes indicates the importance of coupling to rare-earth itinerant 

 electrons. Upon doping, the spectral weight and energy decrease 

 slightly, whereas the modes become overdamped. Our results highlight the 

 role of Mottness in infinite-layer nickelates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000578419100001,

title = {Spectroscopic fingerprint of charge order melting driven by quantum 

 fluctuations in a cuprate (Aug, 10.1038/s41567-020-0993-7, 2020)},

author = {W. S. Lee and Ke-Jin Zhou and M. Hepting and J. Li and A. Nag and A. C. Walters and M. Garcia-Fernandez and H. C. Robarts and M. Hashimoto and H. Lu and B. Nosarzewski and D. Song and H. Eisaki and Z. X. Shen and B. Moritz and J. Zaanen and T. P. Devereaux},

doi = {10.1038/s41567-020-01075-1},

issn = {1745-2473},

year  = {2021},

date = {2021-05-01},

journal = {NATURE PHYSICS},

volume = {17},

number = {5},

pages = {659},

publisher = {NATURE RESEARCH},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {An amendment to this paper has been published and can be accessed via a 

 link at the top of the paper.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000636358400048,

title = {Propagation of shear stress in strongly interacting metallic Fermi 

 liquids enhances transmission of terahertz radiation},

author = {D. Valentinis and J. Zaanen and D. Marel},

doi = {10.1038/s41598-021-86356-2},

issn = {2045-2322},

year  = {2021},

date = {2021-03-01},

journal = {SCIENTIFIC REPORTS},

volume = {11},

number = {1},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {A highlight of Fermi-liquid phenomenology, as explored in neutral 3He, 

 is the observation that in the collisionless regime shear stress 

 propagates as if one is dealing with the transverse phonon of a solid. 

 The existence of this ``transverse zero sound'' requires that the 

 quasiparticle mass enhancement exceeds a critical value. Could such a 

 propagating shear stress also exist in strongly correlated electron 

 systems? Despite some noticeable differences with the neutral case in 

 the Galilean continuum, we arrive at the verdict that transverse zero 

 sound should be generic for mass enhancement higher than 3. We present 

 an experimental setup that should be exquisitely sensitive in this 

 regard: the transmission of terahertz radiation through a thin slab of 

 heavy-fermion material will be strongly enhanced at low temperature and 

 accompanied by giant oscillations, which reflect the interference 

 between light itself and the ``material photon'' being the actual 

 manifestation of transverse zero sound in the charged Fermi liquid.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000627595600002,

title = {Electronic Structure Trends Across the Rare-Earth Series in 

 Superconducting Infinite-Layer Nickelates},

author = {Emily Been and Wei-Sheng Lee and Harold Y. Hwang and Yi Cui and Jan Zaanen and Thomas Devereaux and Brian Moritz and Chunjing Jia},

doi = {10.1103/PhysRevX.11.011050},

issn = {2160-3308},

year  = {2021},

date = {2021-03-01},

journal = {PHYSICAL REVIEW X},

volume = {11},

number = {1},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The recent discovery of superconductivity in oxygen-reduced monovalent 

 nickelates has raised a new platform for the study of unconventional 

 superconductivity, with similarities to and differences from the cuprate 

 high-temperature superconductors. In this paper, we investigate the 

 family of infinite-layer nickelates RNiO2 with rare-earth R spanning 

 across the lanthanide series, introducing a new and nontrivial 

 ``knob'' with which to tune nickelate superconductivity. When 

 traversing from La to Lu, the out-of-plane lattice constant decreases 

 dramatically with an accompanying increase of Ni d(x2-y2) bandwidth; 

 however, surprisingly, the role of oxygen charge transfer diminishes. In 

 contrast, the magnetic exchange grows across the lanthanides, which may 

 be favorable to superconductivity. Moreover, compensation effects from 

 the itinerant 5d electrons present a closer analogy to Kondo lattices, 

 indicating a stronger interplay between charge transfer, bandwidth 

 renormalization, compensation, and magnetic exchange. We also obtain the 

 microscopic Hamiltonian using the Wannier downfolding technique, which 

 will provide the starting point for further many-body theoretical 

 studies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000564497300003,

title = {Spectroscopic fingerprint of charge order melting driven by quantum 

 fluctuations in a cuprate},

author = {W. S. Lee and Ke-Jin J. Zhou and M. Hepting and J. Li and A. Nag and A. C. Walters and M. Garcia-Fernandez and H. C. Robarts and M. Hashimoto and H. Lu and B. Nosarzewski and D. Song and H. Eisaki and Z. X. Shen and B. Moritz and J. Zaanen and T. P. Devereaux},

doi = {10.1038/s41567-020-0993-7},

issn = {1745-2473},

year  = {2021},

date = {2021-01-01},

journal = {NATURE PHYSICS},

volume = {17},

number = {1},

pages = {53+},

publisher = {NATURE RESEARCH},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {X-ray scattering experiments show that the quantum fluctuations 

 associated with charge order take a form that is incompatible with the 

 idea of competition between charge order and superconductivity. 

 Copper oxide high-T(C)superconductors possess a number of exotic orders 

 that coexist with or are proximal to superconductivity. Quantum 

 fluctuations associated with these orders may account for the unusual 

 characteristics of the normal state, and possibly affect the 

 superconductivity(1-4). Yet, spectroscopic evidence for such quantum 

 fluctuations remains elusive. Here, we use resonant inelastic X-ray 

 scattering to reveal spectroscopic evidence of fluctuations associated 

 with a charge order(5-14)in nearly optimally doped Bi2Sr2CaCu2O8+delta. 

 In the superconducting state, while the quasielastic charge order signal 

 decreases with temperature, the interplay between charge order 

 fluctuations and bond-stretching phonons in the form of a Fano-like 

 interference increases, an observation that is incompatible with 

 expectations for competing orders. Invoking general principles, we argue 

 that this behaviour reflects the properties of a dissipative system near 

 an order-disorder quantum critical point, where the dissipation varies 

 with the opening of the pseudogap and superconducting gap at low 

 temperatures, leading to the proliferation of quantum critical 

 fluctuations, which melt charge order.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000552935400002,

title = {Carriers that count},

author = {Jan Zaanen},

doi = {10.1038/s41567-020-0979-5},

issn = {1745-2473},

year  = {2020},

date = {2020-12-01},

journal = {NATURE PHYSICS},

volume = {16},

number = {12},

pages = {1171-1172},

publisher = {NATURE RESEARCH},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {An exactly solvable model for superconductivity includes two crucial 

 features of the cuprates and sheds light on unexplained experiments.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000548166000007,

title = {Electronic structure of the parent compound of superconducting 

 infinite-layer nickelates (vol 91, pg 531, 2020)},

author = {M. Hepting and D. Li and C. J. Jia and H. Lu and E. Paris and Y. Tseng and X. Feng and M. Osada and E. Been and Y. Hikita and Y. -D. Chuang and Z. Hussain and K. J. Zhou and A. Nag and M. Garcia-Fernandez and M. Rossi and H. Y. Huang and D. J. Huang and Z. X. Shen and T. Schmitt and H. Y. Hwang and B. Moritz and J. Zaanen and T. P. Devereaux and W. S. Lee},

doi = {10.1038/s41563-020-0761-1},

issn = {1476-1122},

year  = {2020},

date = {2020-09-01},

journal = {NATURE MATERIALS},

volume = {19},

number = {9},

pages = {1036},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000604139800002,

title = {Ground state phase diagram of the doped Hubbard model on the four-leg 

 cylinder},

author = {Yi-Fan Jiang and Jan Zaanen and Thomas P. Devereaux and Hong-Chen Jiang},

doi = {10.1103/PhysRevResearch.2.033073},

year  = {2020},

date = {2020-07-01},

journal = {PHYSICAL REVIEW RESEARCH},

volume = {2},

number = {3},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {We study the ground state properties of the Hubbard model on a four-leg cylinder with doped hole concentration per site delta <= 12.5% using 

 density-matrix renormalization group. By keeping a large number of 

 states for long system sizes, we find that the nature of the ground 

 state is remarkably sensitive to the presence of next-nearest-neighbor 

 hopping t'. Without t' the ground state of the system corresponds to the 

 insulating filled stripe phase with long-range charge-density-wave (CDW) 

 order, and short-range incommensurate spin correlations appears. 

 However, for a small negative t' a phase characterized by coexisting 

 algebraic d-wave superconducting (SC) and algebraic CDW correlations. In 

 addition, it shows short-range spin- and fermion correlations consistent 

 with a canonical Luther-Emery (LE) liquid, except that the charge and 

 spin periodicities are consistent with half-filled stripes instead of 

 the 4k(F) and 2k(F) wave vectors that are generic for one-dimensional 

 chains. For a small positive t' yet another phase takes over, showing 

 similar SC and CDWcorrelations. However, the fermions are now 

 characterized by a (nearly) infinite correlation length while the gapped 

 spin system is characterized by simple staggered antiferromagnetic 

 correlations. We will show that this is consistent with a LE liquid 

 formed from a weakly coupled (BCS like) d-wave superconductor on the 

 ladder where the interactions have only the effect of stabilizing a 

 cuprate style magnetic resonance.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000508325000004,

title = {Electronic structure of the parent compound of superconducting 

 infinite-layer nickelates},

author = {M. Hepting and D. Li and C. J. Jia and H. Lu and E. Paris and Y. Tseng and X. Feng and M. Osada and E. Been and Y. Hikita and Y. -D. Chuang and Z. Hussain and K. J. Zhou and A. Nag and M. Garcia-Fernandez and M. Rossi and H. Y. Huang and D. J. Huang and Z. X. Shen and T. Schmitt and H. Y. Hwang and B. Moritz and J. Zaanen and T. P. Devereaux and W. S. Lee},

doi = {10.1038/s41563-019-0585-z},

issn = {1476-1122},

year  = {2020},

date = {2020-04-01},

journal = {NATURE MATERIALS},

volume = {19},

number = {4},

pages = {381+},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {The search continues for nickel oxide-based materials with electronic 

 properties similar to cuprate high-temperature superconductors1-10. The 

 recent discovery of superconductivity in the doped infinite-layer 

 nickelate NdNiO2 (refs. 11,12) has strengthened these efforts. Here, we 

 use X-ray spectroscopy and density functional theory to show that the 

 electronic structure of LaNiO2 and NdNiO2, while similar to the 

 cuprates, includes significant distinctions. Unlike cuprates, the 

 rareearth spacer layer in the infinite-layer nickelate supports a weakly 

 interacting three-dimensional 5d metallic state, which hybridizes with a 

 quasi-two-dimensional, strongly correlated state with 3dx2 y2 I symmetry 

 in the NiO2 layers. Thus, the infinite-layer nickelate can be regarded 

 as a sibling of the rare-earth intermetallics13-15, which are well known 

 for heavy fermion behaviour, where the NiO2 correlated layers play an 

 analogous role to the 4f states in rare-earth heavy fermion compounds. 

 This Kondo- or Anderson-lattice-like `oxideintermetallic' replaces the 

 Mott insulator as the reference state from which superconductivity 

 emerges upon doping.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000514392000002,

title = {Isolated zeros destroy Fermi surface in holographic models with a 

 lattice},

author = {Floris Balm and Alexander Krikun and Aurelio Romero-Bermudez and Koenraad Schalm and Jan Zaanen},

doi = {10.1007/JHEP01(2020)151},

issn = {1029-8479},

year  = {2020},

date = {2020-01-01},

journal = {JOURNAL OF HIGH ENERGY PHYSICS},

number = {1},

publisher = {SPRINGER},

address = {ONE NEW YORK PLAZA, SUITE 4600, NEW YORK, NY, UNITED STATES},

abstract = {We study the fermionic spectral density in a strongly correlated quantum 

 system described by a gravity dual. In the presence of periodically 

 modulated chemical potential, which models the effect of the ionic 

 lattice, we explore the shapes of the corresponding Fermi surfaces, 

 defined by the location of peaks in the spectral density at the Fermi 

 level. We find that at strong lattice potentials sectors of the Fermi 

 surface are unexpectedly destroyed and the Fermi surface becomes an 

 arc-like disconnected manifold. We explain this phenomenon in terms of a 

 collision of the Fermi surface pole with zeros of the fermionic Green's 

 function, which are explicitly computable in the holographic dual.},

keywords = {Holography and condensed matter physics (AdS/CMT); Space-Time Symmetries},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000500039200036,

title = {Incoherent strange metal sharply bounded by a critical doping in Bi2212},

author = {Su-Di Chen and Makoto Hashimoto and Yu He and Dongjoon Song and Ke-Jun Xu and Jun-Feng He and Thomas P. Devereaux and Hiroshi Eisaki and Dong-Hui Lu and Jan Zaanen and Zhi-Xun Shen},

doi = {10.1126/science.aaw8850},

issn = {0036-8075},

year  = {2019},

date = {2019-11-01},

journal = {SCIENCE},

volume = {366},

number = {6469},

pages = {1099+},

publisher = {AMER ASSOC ADVANCEMENT SCIENCE},

address = {1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA},

abstract = {In normal metals, macroscopic properties are understood using the 

 concept of quasiparticles. In the cuprate high-temperature 

 superconductors, the metallic state above the highest transition 

 temperature is anomalous and is known as the ``strange metal.'' We 

 studied this state using angle- resolved photoemission spectroscopy. 

 With increasing doping across a temperature-independent critical value 

 p(c) similar to 0.19, we observed that near the Brillouin zone boundary, 

 the strange metal, characterized by an incoherent spectral function, 

 abruptly reconstructs into a more conventional metal with 

 quasiparticles. Above the temperature of superconducting fluctuations, 

 we found that the pseudogap also discontinuously collapses at the very 

 same value of p(c). These observations suggest that the incoherent 

 strange metal is a distinct state and a prerequisite for the pseudogap; 

 such findings are incompatible with existing pseudogap quantum critical 

 point scenarios.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000473016400002,

title = {Anomalous attenuation of plasmons in strange metals and holography},

author = {Aurelio Romero-Bermudez and Alexander Krikun and Koenraad Schalm and Jan Zaanen},

doi = {10.1103/PhysRevB.99.235149},

issn = {2469-9950},

year  = {2019},

date = {2019-06-01},

journal = {PHYSICAL REVIEW B},

volume = {99},

number = {23},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The plasmon is a ubiquitous collective mode in charged liquids. Due to 

 the long-range Coulomb interaction, the massless zero sound mode of the 

 neutral system acquires a finite plasmon frequency in the 

 long-wavelength limit. In the zero-temperature state of conventional 

 metals-the Fermi liquid-the plasmon lives infinitely long at long 

 wavelength when the system is (effectively) translationally invariant. 

 In contrast, we will show that in strongly entangled strange metals the 

 protection of zero sound fails at finite frequency and plasmons are 

 always short lived regardless of their wavelength. Computing the 

 explicit plasmon response in holographic strange metals as an example, 

 we show that decay into the quantum critical continuum replaces Landau 

 damping and this happens for any wavelength.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000468849300010,

title = {Planckian dissipation, minimal viscosity and the transport in cuprate 

 strange metals},

author = {Jan Zaanen},

doi = {10.21468/SciPostPhys.6.5.061},

issn = {2542-4653},

year  = {2019},

date = {2019-05-01},

journal = {SCIPOST PHYSICS},

volume = {6},

number = {5},

publisher = {SCIPOST FOUNDATION},

address = {C/O J S CAUX, INST PHYSICS, UNIV AMSTERDAM, AMSTERDAM, 1098 XH, 

 NETHERLANDS},

abstract = {Could it be that the matter formed from the electrons in high Tc 

 superconductors is of a radically new kind that may be called ``many 

 body entangled compressible quantum matter''? Much of this text is 

 intended as an easy to read tutorial, explaining recent theoretical 

 advances that have been unfolding at the cross roads of condensed 

 matter- and string theory, black hole physics as well as quantum 

 information theory These developments suggest that the physics of such 

 matter may be governed by surprisingly simple principles. My real 

 objective is to present an experimental strategy to test critically 

 whether these principles are actually at work, revolving around the 

 famous linear resistivity characterizing the strange metal phase. The 

 theory suggests a very simple explanation of this ``unreasonably 

 simple'' behavior that is actually directly linked to remarkable 

 results from the study of the quark gluon plasma formed at the heavy ion 

 colliders: the ``fast hydrodynamization'' and the ``minimal 

 viscosity'. This leads to high quality predictions for experiment: the 

 momentum relaxation rate governing the resistivity relates directly to 

 the electronic entropy, while at low temperatures the electron fluid 

 should become unviscous to a degree that turbulent flows can develop 

 even on the nanometre scale.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000466407400005,

title = {Isolated zeros in the spectral function as signature of a quantum 

 continuum},

author = {Nikolay Gnezdilov and Alexander Krikun and Koenraad Schalm and Jan Zaanen},

doi = {10.1103/PhysRevB.99.165149},

issn = {2469-9950},

year  = {2019},

date = {2019-04-01},

journal = {PHYSICAL REVIEW B},

volume = {99},

number = {16},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {We study the observable properties of quantum systems which involve a 

 quantum continuum as a subpart. We show in a very general way that in 

 any system, which consists of at least two isolated states coupled to a 

 continuum, the spectral function of one of the states exhibits an 

 isolated zero at the energy of the other state. Several examples of 

 quantum systems exhibiting such isolated zeros are discussed. Although 

 very general, this phenomenon can be particularly useful as an indirect 

 detection tool for the continuum spectrum in the laboratory realizations 

 of quantum critical behavior.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000454726800018,

title = {Charge trapping and super-Poissonian noise centres in a cuprate 

 superconductor},

author = {K. M. Bastiaans and D. Cho and T. Benschop and I. Battisti and Y. Huang and M. S. Golden and Q. Dong and Y. Jin and J. Zaanen and M. P. Allan},

doi = {10.1038/s41567-018-0300-z},

issn = {1745-2473},

year  = {2018},

date = {2018-12-01},

journal = {NATURE PHYSICS},

volume = {14},

number = {12},

pages = {1183+},

publisher = {NATURE PUBLISHING GROUP},

address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND},

abstract = {The electronic properties of cuprate high-temperature superconductors in 

 their normal state are highly two-dimensional: transport along the 

 crystal planes is perfectly metallic, but is insulating along the 

 perpendicular `c-axis' direction. The ratio of the in-plane to the 

 perpendicular resistance can exceed 10(4) (refs(1-4)). This anisotropy 

 was identified as one of the mysteries of the cuprates early on(5,6), 

 and although widely different proposals exist for its microscopic 

 origin(7-9), there is little empirical information on the microscopic 

 scale. Here, we elucidate the properties of the insulating layers with a 

 newly developed scanning noise spectroscopy technique that can spatially 

 map the current and its time-resolved fluctuations. We discover 

 atomic-scale noise centres that exhibit megahertz current fluctuations 

 40 times the expectation from Poissonian noise, more than what has been 

 observed in mesoscopic systems(10). Such behaviour can happen only in 

 highly polarizable insulators and represents strong evidence for 

 trapping of charge in the charge reservoir layers. Our measurements 

 suggest a picture of metallic layers separated by polarizable insulators 

 within a three-dimensional superconducting state.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000446547100041,

title = {Rapid change of superconductivity and electron-phonon coupling through 

 critical doping in Bi-2212},

author = {Y. He and M. Hashimoto and D. Song and S. -D. Chen and J. He and I. M. Vishik and B. Moritz and D. -H. Lee and N. Nagaosa and J. Zaanen and T. P. Devereaux and Y. Yoshida and H. Eisaki and D. H. Lu and Z. -X. Shen},

doi = {10.1126/science.aar3394},

issn = {0036-8075},

year  = {2018},

date = {2018-10-01},

journal = {SCIENCE},

volume = {362},

number = {6410, SI},

pages = {62+},

publisher = {AMER ASSOC ADVANCEMENT SCIENCE},

address = {1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA},

abstract = {Electron-boson coupling plays a key role in superconductivity for many 

 systems. However, in copper-based high-critical temperature (T-c) 

 superconductors, its relation to superconductivity remains controversial 

 despite strong spectroscopic fingerprints. In this study, we used 

 angle-resolved photoemission spectroscopy to find a pronounced 

 correlation between the superconducting gap and the bosonic coupling 

 strength near the Brillouin zone boundary in Bi2Sr2CaCu2O8+8 . The 

 bosonic coupling strength rapidly increases from the overdoped Fermi 

 liquid regime to the optimally doped strange metal, concomitant with the 

 quadrupled superconducting gap and the doubled gap-to-T-c ratio across 

 the pseudogap boundary. This synchronized lattice and electronic 

 response suggests that the effects of electronic interaction and the 

 electron-phonon coupling (EPC) reinforce each other in a 

 positive-feedback loop upon entering the strange-metal regime, which in 

 turn drives a stronger superconductivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000446186700021,

title = {Doping the holographic Mott insulator},

author = {Tomas Andrade and Alexander Krikun and Koenraad Schalm and Jan Zaanen},

doi = {10.1038/s41567-018-0217-6},

issn = {1745-2473},

year  = {2018},

date = {2018-10-01},

journal = {NATURE PHYSICS},

volume = {14},

number = {10},

pages = {1049+},

publisher = {NATURE PORTFOLIO},

address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},

abstract = {Mott insulators form because of strong electron repulsions and are at 

 the heart of strongly correlated electron physics. Conventionally these 

 are understood as classical `traffic jams' of electrons described by a 

 short-ranged entangled product ground state. Exploiting the holographic 

 duality, which maps the physics of densely entangled matter onto 

 gravitational black hole physics, we show how Mott-like insulators can 

 be constructed departing from entangled non-Fermi liquid metallic 

 states, such as the strange metals found in cuprate superconductors. 

 These `entangled Mott insulators' have traits in common with the 

 `classical' Mott insulators, such as the formation of a Mott gap in the 

 optical conductivity, super-exchange-like interactions and the formation 

 of `stripes' upon doping. They also exhibit new properties: the ordering 

 wavevectors are detached from the number of electrons in the unit cell, 

 and the d.c. resistivity diverges algebraically instead of exponentially 

 as a function of temperature. These results may shed light on the 

 mysterious ordering phenomena observed in underdoped cuprates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000445505000004,

title = {Self-energies and quasiparticle scattering interference},

author = {Miguel Antonio Sulangi and Jan Zaanen},

doi = {10.1103/PhysRevB.98.094518},

issn = {2469-9950},

year  = {2018},

date = {2018-09-01},

journal = {PHYSICAL REVIEW B},

volume = {98},

number = {9},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The cuprate high-temperature superconductors are known to host a wide 

 array of effects due to interactions and disorder. In this paper, we 

 look at some of the consequences of these effects which can be 

 visualized by scanning tunneling spectroscopy in order to provide a 

 guide for future experiments. These interaction and disorder effects can 

 be incorporated into a mean-field description by means of a self-energy 

 appearing in the Green's function. We first examine the quasiparticle 

 scattering interference (QPI) spectra in the superconducting state at 

 optimal doping as temperature is increased. Assuming agreement with 

 angle-resolved photoemission experiments which suggest that the 

 scattering rate depends on temperature, resulting in the filling of the 

 d-wave gap, we find that the peaks predicted by the octet model become 

 progressively smeared as temperature is increased. When the scattering 

 rate is of the same order of magnitude as the superconducting gap, the 

 spectral function shows Fermi-arc-like patterns, while the power 

 spectrum of the local density of states shows the destruction of the 

 octet-model peaks. We next consider the normal state properties of the 

 optimally-doped cuprates. We model this by adding a marginal Fermi 

 liquid (MFL) self-energy to the normal-state propagator and consider the 

 dependence of the QPI spectra on frequency, temperature, and doping. We 

 demonstrate that the MFL self-energy leads to a smearing of the caustics 

 appearing in the normal-state QPI power spectrum as either temperature 

 or frequency is increased at fixed doping. The smearing is found to be 

 more prominent in the MFL case than in an ordinary Fermi liquid. We also 

 consider the case of a marginal Fermi liquid with a strongly 

 momentum-dependent self-energy which gives rise to a visible 

 ``nodal-antinodal'' dichotomy at the normal state and discuss how the 

 spectra as seen in ARPES and STS differ from both an isotropic metal and 

 a broadened d-wave superconductor. Finally, we discuss how these results 

 become modified in the presence of weak distributed disorder and 

 finite-temperature smearing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000438141900003,

title = {Holographic pump probe spectroscopy},

author = {A. Bagrov and B. Craps and F. Galli and V. Keranen and E. Keski-Vakkuri and J. Zaanen},

doi = {10.1007/JHEP07(2018)065},

issn = {1029-8479},

year  = {2018},

date = {2018-07-01},

journal = {JOURNAL OF HIGH ENERGY PHYSICS},

number = {7},

publisher = {SPRINGER},

address = {233 SPRING ST, NEW YORK, NY 10013 USA},

abstract = {We study the non-linear response of a 2+1 dimensional holographic model 

 with weak momentum relaxation and finite charge density to an 

 oscillatory electric field pump pulse. Following the time evolution of 

 one point functions after the pumping has ended, we find that deviations 

 from thermality are well captured within the linear response theory. For 

 electric pulses with a negligible zero frequency component the response 

 approaches the instantaneously thermalizing form typical of holographic 

 Vaidya models. We link this to the suppression of the amplitude of the 

 quasinormal mode that governs the approach to equilibrium. In the large 

 frequency limit, we are also able to show analytically that the 

 holographic geometry takes the Vaidya form. A simple toy model captures 

 these features of our holographic setup. Computing the 

 out-of-equilibrium probe optical conductivity after the pump pulse, we 

 similarly find that for high-frequency pulses the optical conductivity 

 reaches its final equilibrium value effectively instantaneously. Pulses 

 with significant DC components show exponential relaxation governed by 

 twice the frequency of the vector quasinormal mode that governs the 

 approach to equilibrium for the background solution. We explain this 

 numerical factor in terms of a simple symmetry argument.},

keywords = {Gauge-gravity correspondence; Holography and condensed matter physics   (AdS/CMT)},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000430056200005,

title = {Quasiparticle density of states, localization, and distributed disorder 

 in the cuprate superconductors},

author = {Miguel Antonio Sulangi and Jan Zaanen},

doi = {10.1103/PhysRevB.97.144512},

issn = {2469-9950},

year  = {2018},

date = {2018-04-01},

journal = {PHYSICAL REVIEW B},

volume = {97},

number = {14},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {We explore the effects of various kinds of random disorder on the 

 quasiparticle density of states of two-dimensional d-wave 

 superconductors using an exact real-space method, incorporating 

 realistic details known about the cuprates. Random on-site energy and 

 pointlike unitary impurity models are found to give rise to a vanishing 

 DOS at the Fermi energy for narrow distributions and low concentrations, 

 respectively, and lead to a finite, but suppressed, DOS at 

 unrealistically large levels of disorder. Smooth disorder arising from 

 impurities located away from the copper-oxide planes meanwhile gives 

 rise to a finite DOS at realistic impurity concentrations. For the case 

 of smooth disorder whose average potential is zero, a resonance is found 

 at zero energy for the quasiparticle DOS at large impurity 

 concentrations. We discuss the implications of these results on the 

 computed low-temperature specific heat, the behavior of which we find is 

 strongly affected by the amount of disorder present in the system. We 

 also compute the localization length as a function of disorder strength 

 for various types of disorder and find that intermediate-and high-energy 

 states are quasiextended for low disorder, and that states near the 

 Fermi energy are strongly localized and have a localization length that 

 exhibits an unusual dependence on the amount of disorder. We comment on 

 the origin of disorder in the cuprates and provide constraints on these 

 based on known results from scanning tunneling spectroscopy and specific 

 heat experiments.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000429457200009,

title = {Holography and thermalization in optical pump-probe spectroscopy},

author = {A. Bagrov and B. Craps and F. Galli and V. Keranen and E. Keski-Vakkuri and J. Zaanen},

doi = {10.1103/PhysRevD.97.086005},

issn = {2470-0010},

year  = {2018},

date = {2018-04-01},

journal = {PHYSICAL REVIEW D},

volume = {97},

number = {8},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {Using holography, we model experiments in which a 2 + 1D strange metal 

 is pumped by a laser pulse into a highly excited state, after which the 

 time evolution of the optical conductivity is probed. We consider a 

 finite-density state with mildly broken translation invariance and 

 excite it by oscillating electric field pulses. At zero density, the 

 optical conductivity would assume its thermalized value immediately 

 after the pumping has ended. At finite density, pulses with significant 

 dc components give rise to slow exponential relaxation, governed by a 

 vector quasinormal mode. In contrast, for high-frequency pulses the 

 amplitude of the quasinormal mode is strongly suppressed, so that the 

 optical conductivity assumes its thermalized value effectively 

 instantaneously. This surprising prediction may provide a stimulus for 

 taking up the challenge to realize these experiments in the laboratory. 

 Such experiments would test a crucial open question faced by applied 

 holography: are its predictions artifacts of the large N limit or do 

 they enjoy sufficient UV independence to hold at least qualitatively in 

 real-world systems?},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000423508900064,

title = {White matter hyperintensity shape and location feature analysis on brain 

 MRI; proof of principle study in patients with diabetes},

author = {Jeroen Bresser and Hugo J. Kuijf and Karlijn Zaanen and Max A. Viergever and Jeroen Hendrikse and Geert Jan Biessels and Utrecht Vasc Cognitive Impairment},

doi = {10.1038/s41598-018-20084-y},

issn = {2045-2322},

year  = {2018},

date = {2018-01-01},

journal = {SCIENTIFIC REPORTS},

volume = {8},

publisher = {NATURE PUBLISHING GROUP},

address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND},

abstract = {Cerebral small vessel disease is a heterogeneous disease in which 

 various underlying etiologies can lead to different types of white 

 matter hyperintensities (WMH). WMH shape features might aid in 

 distinguishing these different types. In this proof of principle study 

 in patients with type 2 diabetes mellitus (T2DM), we present a novel 

 approach to assess WMH using shape features. Our algorithm determines 

 WMH volume and different WMH shape and location features on 3T MRI scans. These features were compared between patients with T2DM (n = 60) and a matched control group (n = 54). Although a more traditional marker 

 (WMH volume) was not significantly different between groups (natural log 

 transformed Beta (95% CI): 0.07 (-0.11 <-> 0.24)), patients with T2DM 

 showed a larger number of non-punctuate WMH (median (10th-90th 

 percentile), patients: 40 lesions per person (16-86); controls: 26 

 (5-58)) and a different shape (eccentricity) of punctuate deep WMH (Beta 

 (95% CI): 0.40 (0.23 <-> 0.58)) compared to controls. In conclusion, 

 our algorithm identified WMH features that are not part of traditional 

 WMH assessment, but showed to be distinguishing features between 

 patients with T2DM and controls. Future studies could address these 

 features to further unravel the etiology and functional impact of WMH.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000414336400008,

title = {Intertwined Order and Holography: The Case of Parity Breaking Pair 

 Density Waves},

author = {Rong-Gen Cai and Li Li and Yong-Qiang Wang and Jan Zaanen},

doi = {10.1103/PhysRevLett.119.181601},

issn = {0031-9007},

year  = {2017},

date = {2017-11-01},

journal = {PHYSICAL REVIEW LETTERS},

volume = {119},

number = {18},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {We present a minimal bottom-up extension of the Chern-Simons bulk action 

 for holographic translational symmetry breaking that naturally gives 

 rise to pair density waves. We construct stationary inhomogeneous black 

 hole solutions in which both the U(1) symmetry and spatially 

 translational symmetry are spontaneously broken at a finite temperature 

 and charge density. This novel solution provides a dual description of a 

 superconducting phase intertwined with charge, current, and parity 

 orders.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000412515200005,

title = {Dual gauge field theory of quantum liquid crystals in three dimensions},

author = {Aron J. Beekman and Jaakko Nissinen and Kai Wu and Jan Zaanen},

doi = {10.1103/PhysRevB.96.165115},

issn = {2469-9950},

year  = {2017},

date = {2017-10-01},

journal = {PHYSICAL REVIEW B},

volume = {96},

number = {16},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The dislocation-mediated quantum melting of solids into quantum liquid 

 crystals is extended from two to three spatial dimensions, using a 

 generalization of boson-vortex or Abelian-Higgs duality. Dislocations 

 are now Burgers-vector-valued strings that trace out worldsheets in 

 space-time while the phonons of the solid dualize into two-form 

 (Kalb-Ramond) gauge fields. We propose an effective dual Higgs potential 

 that allows for restoring translational symmetry in either one, two, or 

 three directions, leading to the quantum analogues of columnar, smectic, 

 or nematic liquid crystals. In these phases, transverse phonons turn 

 into gapped, propagating modes, while compressional stress remains 

 massless. Rotational Goldstone modes emerge whenever translational 

 symmetry is restored. We also consider the effective electromagnetic 

 response of electrically charged quantum liquid crystals, and find among 

 other things that as a hard principle only two out of the possible three 

 rotational Goldstone modes are observable using propagating 

 electromagnetic fields.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000412512900008,

title = {Revisiting quasiparticle scattering interference in high-temperature 

 superconductors: The problem of narrow peaks},

author = {Miguel Antonio Sulangi and Milan P. Allan and Jan Zaanen},

doi = {10.1103/PhysRevB.96.134507},

issn = {2469-9950},

year  = {2017},

date = {2017-10-01},

journal = {PHYSICAL REVIEW B},

volume = {96},

number = {13},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {We revisit the interpretation of quasiparticle scattering interference 

 in cuprate high-T-c superconductors. This phenomenon has been very 

 successful in reconstructing the dispersions of d-wave Bogoliubov 

 excitations, but the successful identification and interpretation of 

 quasiparticle interference (QPI) in scanning tunneling spectroscopy 

 (STS) experiments rely on theoretical results obtained for the case of 

 isolated impurities. We introduce a highly flexible technique to 

 simulate STS measurements by computing the local density of states using 

 real-space Green's functions defined on two-dimensional lattices with as 

 many as 100 000 sites. We focus on the following question: to what 

 extent can the experimental results be reproduced when various forms of 

 distributed disorder are present? We consider randomly distributed 

 pointlike impurities, smooth ``Coulombic'' disorder, and disorder 

 arising from random on-site energies and superconducting gaps. We find 

 an apparent paradox: the QPI peaks in the Fourier-transformed local 

 density of states appear to be sharper and better defined in experiment 

 than those seen in our simulations. We arrive at a no-go result for 

 smooth-potential disorder since this does not reproduce the QPI peaks 

 associated with large-momentum scattering. An ensemble of pointlike 

 impurities gets closest to experiment, but this goes hand in hand with 

 impurity cores that are not seen in experiment. We also study the 

 effects of possible measurement artifacts (the ``fork mechanism''), 

 which turn out to be of relatively minor consequence. It appears that a 

 more microscopic model of the tunneling process needs to be incorporated 

 in order to account for the sharpness of the experimentally obtained QPI 

 peaks.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000406285700026,

title = {Quantum Thermalization and the Expansion of Atomic Clouds},

author = {Louk Rademaker and Jan Zaanen},

doi = {10.1038/s41598-017-06193-0},

issn = {2045-2322},

year  = {2017},

date = {2017-07-01},

journal = {SCIENTIFIC REPORTS},

volume = {7},

publisher = {NATURE PUBLISHING GROUP},

address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND},

abstract = {The ultimate consequence of quantum many-body physics is that even the 

 air we breathe is governed by strictly unitary time evolution. The 

 reason that we perceive it nonetheless as a completely classical high 

 temperature gas is due to the incapacity of our measurement machines to 

 keep track of the dense many-body entanglement of the gas molecules. The 

 question thus arises whether there are instances where the quantum time 

 evolution of a macroscopic system is qualitatively different from the 

 equivalent classical system? Here we study this question through the 

 expansion of noninteracting atomic clouds. While in many cases the full 

 quantum dynamics is indeed indistinguishable from classical ballistic 

 motion, we do find a notable exception. The subtle quantum correlations 

 in a Bose gas approaching the condensation temperature appear to affect 

 the expansion of the cloud, as if the system has turned into a diffusive 

 collision-full classical system.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000401977000001,

title = {Dual gauge field theory of quantum liquid crystals in two dimensions},

author = {Aron J. Beekman and Jaakko Nissinen and Kai Wu and Ke Liu and Robert-Jan Slager and Zohar Nussinov and Vladimir Cvetkovic and Jan Zaanen},

doi = {10.1016/j.physrep.2017.03.004},

issn = {0370-1573},

year  = {2017},

date = {2017-04-01},

journal = {PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS},

volume = {683},

pages = {1-110},

publisher = {ELSEVIER},

address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS},

abstract = {We present a self-contained review of the theory of dislocation-mediated 

 quantum melting at zero temperature in two spatial dimensions. The 

 theory describes the liquid-crystalline phases with spatial symmetries 

 in between a quantum crystalline solid and an isotropic superfluid: 

 quantum nematics and smectics. It is based on an Abelian-Higgs-type 

 duality mapping of phonons onto gauge bosons (''stress photons''), 

 which encode for the capacity of the crystal to propagate stresses. 

 Dislocations and disclinations, the topological defects of the crystal, 

 are sources for the gauge fields and the melting of the crystal can be 

 understood as the proliferation (condensation) of these defects, giving 

 rise to the Anderson-Higgs mechanism on the dual side. For the liquid 

 crystal phases, the shear sector of the gauge bosons becomes massive 

 signaling that shear rigidity is lost. After providing the necessary 

 background knowledge, including the order parameter theory of 

 two-dimensional quantum liquid crystals and the dual theory of stress 

 gauge bosons in bosonic crystals, the theory of melting is developed 

 step-by-step via the disorder theory of dislocation-mediated melting. 

 Resting on symmetry principles, we derive the phenomenological imaginary 

 time actions of quantum nematics and smectics and analyze the full 

 spectrum of collective modes. The quantum nematic is a superfluid having 

 a true rotational Goldstone mode due to rotational symmetry breaking, 

 and the origin of this `deconfined' mode is traced back to the 

 crystalline phase. The two-dimensional quantum smectic turns out to be a 

 dizzyingly anisotropic phase with the collective modes interpolating 

 between the solid and nematic in a non-trivial way. We also consider 

 electrically charged bosonic crystals and liquid crystals, and carefully 

 analyze the electromagnetic response of the quantum liquid crystal 

 phases. In particular, the quantum nematic is a real superconductor and 

 shows the Meissner effect. Their special properties inherited from 

 spatial symmetry breaking show up mostly at finite momentum, and should 

 be accessible by momentum-sensitive spectroscopy. (C) 2017 Elsevier B.V. 

 All rights reserved.},

keywords = {Quantum liquid crystals; Quantum phase transitions; Abelian-Higgs   duality; Superconductivity},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000402832100002,

title = {Entanglement entropies and fermion signs of critical metals},

author = {N. Kaplis and F. Krueger and J. Zaanen},

doi = {10.1103/PhysRevB.95.155102},

issn = {2469-9950},

year  = {2017},

date = {2017-04-01},

journal = {PHYSICAL REVIEW B},

volume = {95},

number = {15},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The fermion sign problem is often viewed as a sheer inconvenience that 

 plagues numerical studies of strongly interacting electron systems. Only 

 recently has it been suggested that fermion signs are fundamental for 

 the universal behavior of critical metallic systems and crucially 

 enhance their degree of quantum entanglement. In this work we explore 

 potential connections between emergent scale invariance of fermion sign 

 structures and scaling properties of bipartite entanglement entropies. 

 Our analysis is based on a wave-function Ansatz that incorporates 

 collective, long-range backflow correlations into fermionic Slater 

 determinants. Such wave functions mimic the collapse of a Fermi liquid 

 at a quantum critical point. Their nodal surfaces, a representation of 

 the fermion sign structure in many-particle configurations space, show 

 fractal behavior up to a length scale xi that diverges at a critical 

 backflow strength. We show that the Hausdorff dimension of the fractal 

 nodal surface depends on xi, the number of fermions and the exponent of 

 the backflow. For the same wave functions we numerically calculate the 

 second Renyi entanglement entropy S-2. Our results show a crossover from volume scaling, S-2 similar to l(theta). (theta = 2 in d = 2 

 dimensions), to the characteristic Fermi-liquid behavior S-2 similar to 

 l 1n similar to on scales larger than xi. We find that volume scaling of 

 the entanglement entropy is a robust feature of critical backflow 

 fermions, independent of the backflow exponent and hence the fractal 

 dimension of the scale invariant sign structure.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000396035800010,

title = {Hierarchy of orientational phases and axial anisotropies in the gauge 

 theoretical description of generalized nematic liquid crystals},

author = {Ke Liu and Jaakko Nissinen and Josko Boer and Robert-Jan Slager and Jan Zaanen},

doi = {10.1103/PhysRevE.95.022704},

issn = {2470-0045},

year  = {2017},

date = {2017-02-01},

journal = {PHYSICAL REVIEW E},

volume = {95},

number = {2},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The paradigm of spontaneous symmetry breaking encompasses the breaking 

 of the rotational symmetries O(3) of isotropic space to a discrete 

 subgroup, i.e., a three-dimensional point group. The subgroups form a 

 rich hierarchy and allow for many different phases of matter with 

 orientational order. Such spontaneous symmetry breaking occurs in 

 nematic liquid crystals, and a highlight of such anisotropic liquids is 

 the uniaxial and biaxial nematics. Generalizing the familiar uniaxial 

 and biaxial nematics to phases characterized by an arbitrary point-group 

 symmetry, referred to as generalized nematics, leads to a large 

 hierarchy of phases and possible orientational phase transitions. We 

 discuss how a particular class of nematic phase transitions related to 

 axial point groups can be efficiently captured within a recently 

 proposed gauge theoretical formulation of generalized nematics [K. 

 Liu, J. Nissinen, R.- J. Slager, K. Wu, and J. Zaanen, Phys. Rev. X 6, 

 041025 (2016)]. These transitions can be introduced in the model by 

 considering anisotropic couplings that do not break any additional 

 symmetries. By and large this generalizes the well-known 

 uniaxial-biaxial nematic phase transition to any arbitrary axial point 

 group in three dimensions. We find in particular that the generalized 

 axial transitions are distinguished by two types of phase diagrams with 

 intermediate vestigial orientational phases and that the window of the 

 vestigial phase is intimately related to the amount of symmetry of the 

 defining point group due to inherently growing fluctuations of the order 

 parameter. This might explain the stability of the observed 

 uniaxial-biaxial phases as compared to the yet to be observed other 

 possible forms of generalized nematic order with higher point-group 

 symmetries.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000392043500011,

title = {Universality of pseudogap and emergent order in lightly doped Mott 

 insulators},

author = {I. Battisti and K. M. Bastiaans and V. Fedoseev and A. Torre and N. Iliopoulos and A. Tamai and E. C. Hunter and R. S. Perry and J. Zaanen and F. Baumberger and M. P. Allan},

doi = {10.1038/NPHYS3894},

issn = {1745-2473},

year  = {2017},

date = {2017-01-01},

journal = {NATURE PHYSICS},

volume = {13},

number = {1},

pages = {21-25},

publisher = {NATURE PUBLISHING GROUP},

address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND},

abstract = {It is widely believed that high-temperature superconductivity in the 

 cuprates emerges from doped Mott insulators'. When extra carriers are 

 inserted into the parent state, the electrons become mobile but the 

 strong correlations from the Mott state are thought to survive 

 inhomogeneous electronic order, a mysterious pseudogap and, eventually, 

 superconductivity appear. How the insertion of dopant atoms drives this 

 evolution is not known, nor is whether these phenomena are mere 

 distractions specific to hole-doped cuprates or represent genuine 

 physics of doped Mott insulators. Here we visualize the evolution of the 

 electronic states of (Sr1-xLax)(2)IrO4, which is an effective spin-1/2 

 Mott insulator like the cuprates, but is chemically radically 

 different(2,3). Using spectroscopic-imaging scanning tunnelling 

 microscopy (SI-STM), we find that for a doping concentration of x 

 approximate to 5%, an inhomogeneous, phase separated state emerges, 

 with the nucleation of pseudogap puddles around clusters of dopant 

 atoms. Within these puddles, we observe the same iconic electronic order 

 that is seen in underdoped cupratesle(1,4-9). We investigate the genesis 

 of this state and find evidence at low doping for deeply trapped 

 carriers, leading to fully gapped spectra, which abruptly collapse at a 

 threshold of x approximate to 4%. Our results clarify the melting of 

 the Mott state, and establish phase separation and electronic order as 

 generic features of doped Mott insulators.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000387686000001,

title = {Holographic fermions at strong translational symmetry breaking: a 

 Bianchi-VII case study},

author = {A. Bagrov and N. Kaplis and A. Krikun and K. Schalm and J. Zaanen},

doi = {10.1007/JHEP11(2016)057},

issn = {1029-8479},

year  = {2016},

date = {2016-11-01},

journal = {JOURNAL OF HIGH ENERGY PHYSICS},

number = {11},

publisher = {SPRINGER},

address = {233 SPRING ST, NEW YORK, NY 10013 USA},

abstract = {It is presently unknown how strong lattice potentials influence the 

 fermion spectral function of the holographic strange metals predicted by 

 the AdS/CFT correspondence. This embodies a crucial test for the 

 application of holography to condensed matter experiments. We show that 

 for one particular momentum direction this spectrum can be computed for 

 arbitrary strength of the effective translational symmetry breaking 

 potential of the so-called Bianchi-VII geometry employing ordinary 

 differential equations. Deep in the strange metal regime we find rather 

 small changes to the single-fermion response computed by the emergent 

 quantum critical IR, even when the potential becomes relevant in the 

 infra-red. However, in the regime where holographic quasi-particles 

 occur, defining a Fermi surface in the continuum, they acquire a finite 

 lifetime at any finite potential strength. At the transition from 

 irrelevancy to relevancy of the Bianchi potential in the deep infra-red 

 the quasi-particle remnants disappear completely and the fermion 

 spectrum exhibits a purely relaxational behaviour.},

keywords = {Holography and condensed matter physics (AdS/CMT); Space-Time Symmetries},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000386652100001,

title = {Generalized Liquid Crystals: Giant Fluctuations and the Vestigial Chiral 

 Order of \textit{I}, \textit{O}, and \textit{T} Matter},

author = {Ke Liu and Jaakko Nissinen and Robert-Jan Slager and Kai Wu and Jan Zaanen},

doi = {10.1103/PhysRevX.6.041025},

issn = {2160-3308},

year  = {2016},

date = {2016-10-01},

journal = {PHYSICAL REVIEW X},

volume = {6},

number = {4},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The physics of nematic liquid crystals has been the subject of intensive 

 research since the late 19th century. However, the focus of this pursuit 

 has been centered around uniaxial and biaxial nematics associated with 

 constituents bearing a D-infinity h or D-2h symmetry, respectively. In 

 view of general symmetries, however, these are singularly special since 

 nematic order can in principle involve any point-group symmetry. Given 

 the progress in tailoring nanoparticles with particular shapes and 

 interactions, this vast family of ``generalized nematics'' might 

 become accessible in the laboratory. Little is known because the order 

 parameter theories associated with the highly symmetric point groups are 

 remarkably complicated, involving tensor order parameters of high rank. 

 Here, we show that the generic features of the statistical physics of 

 such systems can be studied in a highly flexible and efficient fashion 

 using a mathematical tool borrowed from high-energy physics: discrete 

 non-Abelian gauge theory. Explicitly, we construct a family of lattice 

 gauge models encapsulating nematic ordering of general three-dimensional 

 point-group symmetries. We find that the most symmetrical generalized 

 nematics are subjected to thermal fluctuations of unprecedented 

 severity. As a result, novel forms of fluctuation phenomena become 

 possible. In particular, we demonstrate that a vestigial phase carrying 

 no more than chiral order becomes ubiquitous departing from high 

 point-group symmetry chiral building blocks, such as I, O, and T 

 symmetric matter.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000381804900025,

title = {Superconducting electrons go missing},

author = {Jan Zaanen},

doi = {10.1038/536282a},

issn = {0028-0836},

year  = {2016},

date = {2016-08-01},

journal = {NATURE},

volume = {536},

number = {7616},

pages = {282-283},

publisher = {NATURE PUBLISHING GROUP},

address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000381492200014,

title = {Classification of point-group-symmetric orientational ordering tensors},

author = {Jaakko Nissinen and Ke Liu and Robert-Jan Slager and Kai Wu and Jan Zaanen},

doi = {10.1103/PhysRevE.94.022701},

issn = {2470-0045},

year  = {2016},

date = {2016-08-01},

journal = {PHYSICAL REVIEW E},

volume = {94},

number = {2},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {The concept of symmetry breaking has been a propelling force in 

 understanding phases of matter. While rotational-symmetry breaking is 

 one of the most prevalent examples, the rich landscape of orientational 

 orders breaking the rotational symmetries of isotropic space, i.e., 

 O(3), to a three-dimensional point group remain largely unexplored, 

 apart from simple examples such as ferromagnetic or uniaxial nematic 

 ordering. Here we provide an explicit construction, utilizing a recently 

 introduced gauge-theoretical framework, to address the three-dimensional 

 point-group-symmetric orientational orders on a general footing. This 

 unified approach allows us to enlist order parameter tensors for all 

 three-dimensional point groups. By construction, these tensor order 

 parameters are the minimal set of simplest tensors allowed by the 

 symmetries that uniquely characterize the orientational order. We 

 explicitly give these for the point groups C-n, D-n, T, O, I subset 

 of SO(3) and C-nv, S-2n, C-nh, D-nh, D-nd, T-h, T-d, O-h, I-h subset 

 of O(3) for n, 2n is an element of1,2,3,4,6,infinity. This central 

 result may be perceived as a road map for identifying exotic 

 orientational orders that may become more and more in reach in view of 

 rapid experimental progress in, e.g., nanocolloidal systems and novel 

 magnets.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000379660900001,

title = {Probing the Nuclear Spin-Lattice Relaxation Time at the Nanoscale},

author = {J. J. T. Wagenaar and A. M. J. Haan and J. M. Voogd and L. Bossoni and T. A. Jong and M. Wit and K. M. Bastiaans and D. J. Thoen and A. Endo and T. M. Klapwijk and J. Zaanen and T. H. Oosterkamp},

doi = {10.1103/PhysRevApplied.6.014007},

issn = {2331-7019},

year  = {2016},

date = {2016-07-01},

journal = {PHYSICAL REVIEW APPLIED},

volume = {6},

number = {1},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {Nuclear spin-lattice relaxation times are measured on copper using 

 magnetic-resonance force microscopy performed at temperatures down to 42 

 mK. The low temperature is verified by comparison with the Korringa 

 relation. Measuring spin-lattice relaxation times locally at very low 

 temperatures opens up the possibility to measure the magnetic properties 

 of inhomogeneous electron systems realized in oxide interfaces, 

 topological insulators, and other strongly correlated electron systems 

 such as high-T-c superconductors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000377302000007,

title = {Self-organized pseudo-graphene on grain boundaries in topological band 

 insulators},

author = {Robert-Jan Slager and Vladimir Juricic and Ville Lahtinen and Jan Zaanen},

doi = {10.1103/PhysRevB.93.245406},

issn = {2469-9950},

year  = {2016},

date = {2016-06-01},

journal = {PHYSICAL REVIEW B},

volume = {93},

number = {24},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {Semimetals are characterized by nodal band structures that give rise to 

 exotic electronic properties. The stability of Dirac semimetals, such as 

 graphene in two spatial dimensions, requires the presence of lattice 

 symmetries, while akin to the surface states of topological band 

 insulators, Weyl semimetals in three spatial dimensions are protected by 

 band topology. Here we show that in the bulk of topological band 

 insulators, self-organized topologically protected semimetals can emerge 

 along a grain boundary, a ubiquitous extended lattice defect in any 

 crystalline material. In addition to experimentally accessible 

 electronic transport measurements, these states exhibit a valley anomaly 

 in two dimensions influencing edge spin transport, whereas in three 

 dimensions they appear as graphenelike states that may exhibit an 

 odd-integer quantum Hall effect. The general mechanism underlying these 

 semimetals-the hybridization of spinon modes bound to the grain 

 boundary-suggests that topological semimetals can emerge in any 

 topological material where lattice dislocations bind localized 

 topological modes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000371597500020,

title = {Electrons go with the flow in exotic material systems},

author = {Jan Zaanen},

doi = {10.1126/science.aaf2487},

issn = {0036-8075},

year  = {2016},

date = {2016-03-01},

journal = {SCIENCE},

volume = {351},

number = {6277},

pages = {1026-1027},

publisher = {AMER ASSOC ADVANCEMENT SCIENCE},

address = {1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{WOS:000363529300012,

title = {Exciton-driven quantum phase transitions in holography},

author = {E. Gubankova and M. Cubrovic and J. Zaanen},

doi = {10.1103/PhysRevD.92.086004},

issn = {1550-7998},

year  = {2015},

date = {2015-10-01},

journal = {PHYSICAL REVIEW D},

volume = {92},

number = {8},

publisher = {AMER PHYSICAL SOC},

address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA},

abstract = {We study phase transitions driven by fermionic double-trace deformations 

 in gauge-gravity duality. Both the strength of the double-trace 

 deformation and the infrared conformal dimension/self-energy scaling of 

 the quasiparticle can be used to decrease the critical temperature to 

 zero, leading to a line of quantum critical points. The self-energy 

 scaling is controlled indirectly through an applied magnetic field and 

 the quantum phase transition naturally involves the condensation of a 

 fermion bilinear which models the spin density wave in an 

 antiferromagnetic state. The nature of the quantum critical points 

 depends on the parameters and we find either a 

 Berezinsky-Kosterliz-Touless-type transition or one of two distinct 

 second-order transitions with non-mean-field exponents. One of these is 

 an anomalous branch where the order parameter of constituent non-Fermi 

 liquid quasiparticles is enhanced by the magnetic field. Stabilization 

 of ordered non-Fermi liquids by a strong magnetic field is observed in 

 experiments with highly oriented pyrolytic graphite.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}