Carrier Injection and Manipulation of Charge-Density Wave in Kagome Superconductor CsV 3 Sb 5 Kosuke Nakayama, Yongkai Li, Takemi Kato, Min Liu, Zhiwei Wang, Takashi Takahashi, Yugui Yao, and Takafumi Sato Phys. Rev. X 12, 011001 (2022) – Published 3 January 2022 Dosing cesium atoms on the surface of CsV 3 Sb 5 suppresses the charge-density wave that typically coexists with its superconductivity, paving the way to understanding the interplay between these two phenomena. Show Abstract Condensed Matter Physics Materials Science Superconductivity PDFHTML Asymmetric Attosecond Photoionization in Molecular Shape Resonance Xiaochun Gong, Wenyu Jiang, Jihong Tong, Junjie Qiang, Peifen Lu, Hongcheng Ni, Robert Lucchese, Kiyoshi Ueda, and Jian Wu Phys. Rev. X 12, 011002 (2022) – Published 4 January 2022 A technique for timing the photoemission from a molecule shows an attosecond-scale delay of the electron wave packet from opposite ends of the molecule, thus demonstrating a new tool for exploring photoelectron dynamics. Show Abstract Atomic and Molecular Physics Chemical Physics Optics PDFHTML Blue Phase III: Topological Fluid of Skyrmions J. Pišljar, S. Ghosh, S. Turlapati, N. V. S. Rao, M. Škarabot, A. Mertelj, A. Petelin, A. Nych, M. Marinčič, A. Pusovnik, M. Ravnik, and I. Muševič Phys. Rev. X 12, 011003 (2022) – Published 5 January 2022 Optical microscopy reveals that blue phases—molecularly ordered liquids—consist of filaments with vortexlike cross sections known as skyrmions, whirls in a material, with possible information-storage applications. Show Abstract Soft Matter PDFHTML Disentangling Homophily, Community Structure, and Triadic Closure in Networks Tiago P. Peixoto Phys. Rev. X 12, 011004 (2022) – Published 6 January 2022 A method for analyzing networks can distinguish between two commonly conflated mechanisms for generating connections between nodes, thus improving understanding of how various networks form. Show Abstract Complex Systems Statistical Physics PDFHTML Demonstration of Density Matrix Exponentiation Using a Superconducting Quantum Processor M. Kjaergaard, M. E. Schwartz, A. Greene, G. O. Samach, A. Bengtsson, M. O’Keeffe, C. M. McNally, J. Braumüller, D. K. Kim, P. Krantz, M. Marvian, A. Melville, B. M. Niedzielski, Y. Sung, R. Winik, J. Yoder, D. Rosenberg, K. Obenland, S. Lloyd, T. P. Orlando, I. Marvian, S. Gustavsson, and W. D. Oliver Phys. Rev. X 12, 011005 (2022) – Published 7 January 2022 Density matrix exponentiation may offer a natively quantum approach to programming quantum computers. A new experiment presents the first demonstration of the protocol in a superconducting quantum processor. Show Abstract Quantum Information PDFHTML Probing Symmetries of Quantum Many-Body Systems through Gap Ratio Statistics Olivier Giraud, Nicolas Macé, Éric Vernier, and Fabien Alet Phys. Rev. X 12, 011006 (2022) – Published 10 January 2022 The statistics of ratios between successive energy levels in certain quantum systems can reveal additional, possibly hidden, symmetries as well as distinguish between regular and chaotic behavior. Show Abstract Interdisciplinary Physics Quantum Physics PDFHTML Quantum Adaptive Agents with Efficient Long-Term Memories Thomas J. Elliott, Mile Gu, Andrew J. P. Garner, and Jayne Thompson Phys. Rev. X 12, 011007 (2022) – Published 11 January 2022 Quantum information processing can provide a significant competitive advantage for any system that must adapt to its environment, an enhancement that scales without bound. Show Abstract Complex Systems Quantum Information PDFHTML Realization of a Universal Quantum Gate Set for Itinerant Microwave Photons Kevin Reuer, Jean-Claude Besse, Lucien Wernli, Paul Magnard, Philipp Kurpiers, Graham J. Norris, Andreas Wallraff, and Christopher Eichler Phys. Rev. X 12, 011008 (2022) – Published 12 January 2022 Using superconducting circuits, an experiment demonstrates a set of universal gates for quantum computing with microwave photon qubits, which could find use in future distributed quantum networks. Show Abstract Condensed Matter Physics Quantum Physics Quantum Information PDFHTML Sources of Low-Energy Events in Low-Threshold Dark-Matter and Neutrino Detectors Peizhi Du, Daniel Egana-Ugrinovic, Rouven Essig, and Mukul Sholapurkar Phys. Rev. X 12, 011009 (2022) – Published 13 January 2022 In dark-matter detectors, three processes that arise from interactions with high-energy particles mimic sought-after signals, explaining observed excesses and requiring mitigation to discover low-mass dark matter. Show Abstract Cosmology Particles and Fields PDFHTML Node Metadata Can Produce Predictability Crossovers in Network Inference Problems Oscar Fajardo-Fontiveros, Roger Guimerà, and Marta Sales-Pardo Phys. Rev. X 12, 011010 (2022) – Published 14 January 2022 Gradually adding metadata to a complex network causes a crossover in the ability to infer properties and make predictions about that network. Show Abstract Complex Systems Statistical Physics PDFHTML Theory of Gating in Recurrent Neural Networks Kamesh Krishnamurthy, Tankut Can, and David J. Schwab Phys. Rev. X 12, 011011 (2022) – Published 18 January 2022 The success of recurrent neural networks owes much to gating, a multiplicative interaction that controls the flow of information. New models lead to a comprehensive theory of gating that can help engineers and neuroscientists. Show Abstract Interdisciplinary Physics Nonlinear Dynamics Statistical Physics PDFHTML Mapping Lamb, Stark, and Purcell Effects at a Chromophore-Picocavity Junction with Hyper-Resolved Fluorescence Microscopy Anna Rosławska, Tomáš Neuman, Benjamin Doppagne, Andrei G. Borisov, Michelangelo Romeo, Fabrice Scheurer, Javier Aizpurua, and Guillaume Schull Phys. Rev. X 12, 011012 (2022) – Published 19 January 2022 By leveraging fluorescence from a single molecule, new microscopy techniques provide direct visualizations of charge oscillation and redistribution within the excited molecule. Show Abstract Condensed Matter Physics Plasmonics PDFHTML Ultrafast Renormalization of the On-Site Coulomb Repulsion in a Cuprate Superconductor Denitsa R. Baykusheva, Hoyoung Jang, Ali A. Husain, Sangjun Lee, Sophia F. R. TenHuisen, Preston Zhou, Sunwook Park, Hoon Kim, Jin-Kwang Kim, Hyeong-Do Kim, Minseok Kim, Sang-Youn Park, Peter Abbamonte, B. J. Kim, G. D. Gu, Yao Wang, and Matteo Mitrano Phys. Rev. X 12, 011013 (2022) – Published 20 January 2022 Ultrafast pulses from an infrared laser reduce the effective repulsion between electrons in a high-temperature superconductor, showcasing a new way to manipulate electronic interactions using light. Show Abstract Condensed Matter Physics Strongly Correlated Materials Superconductivity PDFHTML Specific Heat of the Kagome Antiferromagnet Herbertsmithite in High Magnetic Fields Quentin Barthélemy, Albin Demuer, Christophe Marcenat, Thierry Klein, Bernard Bernu, Laura Messio, Matias Velázquez, Edwin Kermarrec, Fabrice Bert, and Philippe Mendels Phys. Rev. X 12, 011014 (2022) – Published 21 January 2022 New measurements of herbertsmithite isolate the role of spins on the vertices of its triangular kagome atomic lattice to its quantum spin-liquid ground state. Show Abstract Condensed Matter Physics Magnetism Strongly Correlated Materials PDFHTML Reservoir-Engineered Spin Squeezing: Macroscopic Even-Odd Effects and Hybrid-Systems Implementations Peter Groszkowski, Martin Koppenhöfer, Hoi-Kwan Lau, and A. A. Clerk Phys. Rev. X 12, 011015 (2022) – Published 24 January 2022 A new way to stabilize highly entangled spin-squeezed states for precision sensing is simpler to implement and exhibits an unusual sensitivity to the number of spins as well as emergent slow timescales. Show Abstract Quantum Physics Quantum Information PDFHTML Mott-Driven BEC-BCS Crossover in a Doped Spin Liquid Candidate κ − ( BEDT − TTF ) 4 Hg 2.89 Br 8 Y. Suzuki, K. Wakamatsu, J. Ibuka, H. Oike, T. Fujii, K. Miyagawa, H. Taniguchi, and K. Kanoda Phys. Rev. X 12, 011016 (2022) – Published 25 January 2022 A doped quantum spin-liquid candidate transitions from one regime of superconductor electron pairing to another as pressure increases, thus widening the potential hosts of unconventional superconductivity. Show Abstract Condensed Matter Physics Strongly Correlated Materials Superconductivity PDFHTML CaCu 3 Ru 4 O 12 : A High-Kondo-Temperature Transition-Metal Oxide D. Takegami et al. Phys. Rev. X 12, 011017 (2022) – Published 26 January 2022 Evidence of the Kondo effect—a hallmark of interacting electrons—in a transition-metal oxide provides new insight into the rich electronic behavior of these materials and a new platform for studying correlated physics. Show Abstract Condensed Matter Physics Magnetism PDFHTML Probing Many-Body Quantum Chaos with Quantum Simulators Lata Kh Joshi, Andreas Elben, Amit Vikram, Benoît Vermersch, Victor Galitski, and Peter Zoller Phys. Rev. X 12, 011018 (2022) – Published 27 January 2022 A class of observables known as partial spectral form factors can efficiently measure signatures of chaos in existing quantum simulators, opening the door to future insights into chaos and thermalization. Show Abstract Condensed Matter Physics Quantum Physics Quantum Information PDFHTML Polarization-Modulated Angle-Resolved Photoemission Spectroscopy: Toward Circular Dichroism without Circular Photons and Bloch Wave-function Reconstruction Michael Schüler, Tommaso Pincelli, Shuo Dong, Thomas P. Devereaux, Martin Wolf, Laurenz Rettig, Ralph Ernstorfer, and Samuel Beaulieu Phys. Rev. X 12, 011019 (2022) – Published 28 January 2022 Complete characterization of certain quantum materials requires knowledge of the complex wave functions that describe electrons in the solid. A new measurement methodology provides deep insights into that information. Show Abstract