Article
Physics, Multidisciplinary
Sudeep Kumar Ghosh, James F. Annett, Jorge Quintanilla
Summary: The study proposes a novel superconducting ground state where microscopic supercurrent loops spontaneously form within a unit cell at the superconducting transition temperature, breaking time-reversal symmetry in the superconducting state. Using Ginzburg-Landau theory, the emergence of these currents in a toy model is detailed, along with the crystallographic symmetry requirements to realize such a state. An upper bound for the resulting internal magnetic fields is estimated and found to be consistent with recent muon-spin relaxation experiments.
NEW JOURNAL OF PHYSICS
(2021)
Article
Multidisciplinary Sciences
Nader Zaki, Genda Gu, Alexei Tsvelik, Congjun Wu, Peter D. Johnson
Summary: Topological superconductivity has been discovered in the high-Tc family of superconductors FeTe1-xSex, with evidence of Majorana fermions in the surface state. High-resolution laser-based photo-emission studies have revealed the interplay of topology, magnetism, and superconductivity in this system, showing the potential for exotic topological phenomena.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Review
Physics, Condensed Matter
Sudeep Kumar Ghosh, Michael Smidman, Tian Shang, James F. Annett, Adrian D. Hillier, Jorge Quintanilla, Huiqiu Yuan
Summary: Superconductivity and magnetism are opposing states of matter, with the presence of spontaneous magnetic fields inside the superconducting state being a fascinating phenomenon that has prompted extensive research. Recent experimental discoveries of unconventional superconductors breaking time-reversal symmetry, along with theoretical efforts to understand their properties, are discussed in this review. The importance of multiple bands in understanding order parameter symmetries and pairing mechanisms is also highlighted.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Review
Physics, Multidisciplinary
Tian Shang, Toni Shiroka
Summary: Recent studies have shown that some rhenium compounds exhibit time-reversal symmetry breaking in their superconducting state, but a satisfactory explanation for this phenomenon is still lacking. Research suggests that the presence and amount of rhenium are key factors affecting the extent of TRS breaking.
FRONTIERS IN PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Dimitri Pimenov, Andrey Chubukov
Summary: In this study, the pairing of fermions is investigated with an interaction involving Hubbard repulsion, a screened Coulomb potential, and a dynamical phonon-mediated attraction. The gap equation allows for even-and odd-frequency solutions Ae and Ao. It is shown that odd-frequency pairing does not develop within the Eliashberg approximation due to over-critical pair breaking from the self-energy, but can develop when vertex corrections are included. Furthermore, Ao remains unaffected by Hubbard repulsion and for strong repulsion, it is comparable to a reduced Ae.
Article
Materials Science, Multidisciplinary
Roland Willa, Matthias Hecker, Rafael M. Fernandes, Joerg Schmalian
Summary: The time-reversal symmetry breaking in the superconducting state of Sr2RuO4 is attributed to inhomogeneous strain fields near edge dislocations of the crystal. The strong strain inhomogeneities generated by dislocations result in a slowly decaying subleading pairing state contributing significantly to the condensate, leading to the local breaking of time-reversal symmetry.
Article
Materials Science, Multidisciplinary
Arushi, R. K. Kushwaha, D. Singh, A. D. Hillier, M. S. Scheurer, R. P. Singh
Summary: We have studied the electronic properties of ScS, a transition-metal monochalcogenide, and confirmed its bulk superconductivity. The presence of spontaneous static or quasistatic magnetic fields in the superconducting state suggests that ScS may be a candidate material for unconventional superconductivity.
Article
Engineering, Electrical & Electronic
Sheng-Chin Ho, Ching-Hao Chang, Yu-Chiang Hsieh, Shun-Tsung Lo, Botsz Huang, Thi-Hai-Yen Vu, Carmine Ortix, Tse-Ming Chen
Summary: Research has shown that lithographically patterned strain can create a non-trivial band structure and exotic phase of matter in bilayer graphene.
NATURE ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Wei Zhang, Xinyou Liu, Lingfei Wang, Chun Wai Tsang, Zheyu Wang, Siu Tung Lam, Wenyan Wang, Jianyu Xie, Xuefeng Zhou, Yusheng Zhao, Shanmin Wang, Jeff Tallon, Kwing To Lai, Swee K. Goh
Summary: The kagome metal CsV3Sb5 exhibits an unusual competition between charge-density-wave (CDW) order and superconductivity. Time reversal symmetry breaking (TRSB) has been observed inside the CDW phase, indicating the emergence of superconductivity from a TRSB normal state and potentially leading to an exotic superconducting state. Through various experiments, it has been confirmed that CsV3Sb5 shows conventional s-wave superconductivity, which is insensitive to disorder and exhibits strong coupling, even in the presence or absence of TRSB.
Article
Materials Science, Multidisciplinary
I. Maccari, J. Carlstroem, E. Babaev
Summary: Recent mean-field calculations indicate that twisted bilayer graphene in its superconducting state may exhibit either a nematic order or a breakdown of time-reversal symmetry. The two-dimensional nature of the material and its high critical temperature compared to the Fermi energy suggest significant fluctuations. Monte Carlo simulations are used to study these fluctuations, revealing a phase with quadrupling fermionic order induced by fluctuations in the proposed model for twisted bilayer graphene. This four-electron condensate, instead of superconductivity, displays spontaneous breaking of time-reversal symmetry. The results suggest that twisted bilayer graphene is a promising platform to study condensates beyond the traditional pair-condensate paradigm.
Article
Materials Science, Multidisciplinary
Andrew C. Yuan, Erez Berg, Steven A. Kivelson
Summary: The study demonstrates that the superconducting state in Sr2RuO4 can degenerate at an assumed tetracritical point. Spatially varying strain can lead to different states of the superconducting state, including those preserving time-reversal symmetry and those breaking it at region boundaries. This research shows that various natural patterns of strain induce a rich variety of superconducting textures, possibly resolving inconsistencies between theoretical proposals and experimental observations.
Article
Physics, Multidisciplinary
Zijian Wang, Qiaoyi Li, Wei Li, Zi Cai
Summary: This article investigates the impact of a quantum bath on symmetry-protected topological edge modes, emphasizing the special role of time-reversal symmetry in open quantum systems. It is found that emergent partial time-reversal symmetry breaking can lead to the diffusion of topological modes from the system edge into the bath, rendering them ineffective for quantum computation.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Fluids & Plasmas
Ramgopal Agrawal, Akhilesh Pandey, Sanjay Puri
Summary: In this study, the breaking of time-reversal invariance in the quantum kicked rotor by the application of a magnetic field was investigated using a finite-dimensional model. The transition from time-reversal invariance to noninvariance in the spectral and eigenvector fluctuations of the quantum kicked rotor was found to be dependent on the ratio of alpha 2/N, where alpha represents the chaos parameter and N is the dimensionality of the evolution operator matrix. The speed of this transition significantly increases as alpha 2/N decreases, showing deviations from random matrix theory in certain cases.
Article
Chemistry, Physical
Bowen Yang, Yin Min Goh, Suk Hyun Sung, Gaihua Ye, Sananda Biswas, David A. S. Kaib, Ramesh Dhakal, Shaohua Yan, Chenghe Li, Shengwei Jiang, Fangchu Chen, Hechang Lei, Rui He, Roser Valenti, Stephen M. Winter, Robert Hovden, Adam W. Tsen
Summary: The authors investigate the magnetic anisotropy in monolayer RuCl3 and observe a transition from easy-plane to easy-axis due to in-plane distortions of Cl atoms. This finding is important for realizing a quantum spin liquid. The study provides insights into the possibility of exploring Kitaev physics in a true two-dimensional limit.
Article
History & Philosophy Of Science
Cristian Lopez, Michael Esfeld
Summary: In this paper, we propose an alternative interpretation of time-reversal symmetry in philosophy of physics: Humean time-reversal symmetry. According to this interpretation, time-reversal symmetry is understood as a heuristic, epistemic virtue of the best system, rather than a property of the Humean mosaic. One consequence of this view is that one of the main arguments against a primitive direction of time is rendered harmless, paving the way for primitivism about the direction of time.
Article
Materials Science, Multidisciplinary
Georgios Varnavides, Yaxian Wang, Philip J. W. Moll, Polina Anikeeva, Prineha Narang
Summary: A theoretical framework for electron transport in single-crystal delafossite metals is presented using a combination of first-principles calculations and numerical modeling. The study investigates different electron and phonon scattering mechanisms and establishes a hierarchy of mean free path for quasiparticles at different temperatures. The anisotropic Fermi surface is explicitly treated to obtain experimentally-accessible transport observables, bridging the diffusive, ballistic, and hydrodynamic transport regime limits. The research provides insights into microscopic interaction mechanisms on open hexagonal Fermi surfaces and their connection to macroscopic electron transport in finite-size channels.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Physics, Applied
Derek S. Wang, David D. Dai, Prineha Narang
Summary: This article describes how a ladder emitter can be used to implement a tunable quantum logic gate on photonic qubits encoded in the frequency basis. By controlling the interactions between different photons, arbitrary phase control operations can be achieved. This gate is deterministic, does not require active control, and only needs a single ladder emitter, allowing for low-footprint and more efficient decomposition of quantum circuits.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Zhigang Song, Yu Wang, Haimei Zheng, Prineha Narang, Lin-Wang Wang
Summary: Recently, there has been significant interest in non-vdW moire superlattices. In this study, we theoretically predict unusual properties based on the chemical bonding between twisted PbS nanosheets. Experimental observations confirm the accessibility and stability of these non-vdW moire superlattices.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
J. Klein, T. Pham, J. D. Thomsen, J. B. Curtis, T. Denneulin, M. Lorke, M. Florian, A. Steinhoff, R. A. Wiscons, J. Luxa, Z. Sofer, F. Jahnke, P. Narang, F. M. Ross
Summary: Van der Waals magnetic materials consist of atomically thin magnetically ordered layers. In this study, the researchers demonstrate nanoscale structural control in the layered magnet CrSBr by using an electron beam, which could lead to the creation of spin textures and quantum magnetic phases.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
A. S. Disa, J. Curtis, M. Fechner, A. Liu, A. von Hoegen, M. Foerst, T. F. Nova, P. Narang, A. Maljuk, A. V. Boris, B. Keimer, A. Cavalleri
Summary: Lattice manipulation through optical methods can enhance and stabilize high-temperature ferromagnetism, expanding the potential applications of YTiO3.
Review
Nanoscience & Nanotechnology
Georgios Varnavides, Amir Yacoby, Claudia Felser, Prineha Narang
Summary: As high-quality single-crystal materials used in electronic devices reach smaller scales, charge-transport phenomena lead to inhomogeneous spatial signatures with significant effects on material properties. These signatures, including spatially varying dissipation and interface resistance, are crucial for device control. This Review examines the inhomogeneous charge flow signatures in conductors, focusing on electron hydrodynamics, where electrons exhibit strong interactions and flow collectively like fluids. Recent experimental advances and theoretical frameworks are discussed, along with new charge-transport phenomena introduced by crystal symmetry in materials.
NATURE REVIEWS MATERIALS
(2023)
Article
Multidisciplinary Sciences
Bohan Li, Aritra Das, Spyros Tserkis, Prineha Narang, Ping Koy Lam, Syed M. Assad
Summary: The maximum entanglement achievable through passive transformations by continuous-variable states is called the entanglement potential. Recent research indicates that the entanglement potential can be upper-bounded by a simple function of squeezing of formation. Certain classes of two-mode Gaussian states can saturate this bound, but it remains an open problem for the general case. In this study, a larger class of states is introduced that is proven to saturate the bound, and it is conjectured that all two-mode Gaussian states can be passively transformed into this class, thereby equating entanglement potential with squeezing of formation. An explicit algorithm for the passive transformations is provided, and extensive numerical testing is performed to support this claim, aiming to unify the resource theories of two characteristic quantum properties of continuous-variable systems.
SCIENTIFIC REPORTS
(2023)
Article
Physics, Multidisciplinary
Jonathan B. Curtis, Ankit Disa, Michael Fechner, Andrea Cavalleri, Prineha Narang
Summary: By using intense coherent electromagnetic radiation, the properties of quantum materials can be manipulated quickly and induce potentially useful phases absent in equilibrium. Recent experiments on spin-orbital ferromagnet YTiO3 inspire the discussion on the nonequilibrium dynamics of a Heisenberg ferromagnetic insulator with low-lying orbital excitations. The dynamics of the magnon excitations in this system are modeled, showing that specially targeted optical pulses can exert greater control over the magnetization dynamics by dynamically coupling the orbitals with the low-lying magnons.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Jonathan B. Curtis, Nicholas R. Poniatowski, Amir Yacoby, Prineha Narang
Summary: This study presents a platform for spectroscopic probing of unconventional superconductivity in thin-layer materials through the proximity effect. The observation of changes in collective modes and condensation provides insights into the pairing interactions and superconducting properties of the materials.
Article
Optics
Justin H. Wilson, Jonathan B. Curtis, Victor M. Galitski
Summary: This study demonstrates that Goldstone modes in a flowing spinor Bose-Einstein condensate behave similarly to linear dispersive modes coupled to an Einstein-Hilbert metric, exhibiting phenomena from quantum field theory in curved space. The kind of spacetime (Einstein-Hilbert or Newton-Cartan) is linked to the mean-field phase of the condensate, and different energy and momentum currents can be computed and related in these analog systems.
Article
Physics, Multidisciplinary
Ian MacCormack, Conor Delaney, Alexey Galda, Nidhi Aggarwal, Prineha Narang
Summary: Neural-network-based algorithms have been widely studied for their ability in learning complex patterns and classifying quantum and classical data sets. This paper introduces a new algorithm, branching quantum convolutional neural network (bQCNN), which leverages a branching structure and midcircuit measurement results to enhance expressibility. Experimental results show that bQCNN outperforms ordinary QCNN in specific tasks. This algorithm has potential applications in noisy intermediate-scale quantum devices.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
Jonathan B. Curtis, Andrey Grankin, Nicholas R. Poniatowski, Victor M. Galitski, Prineha Narang, Eugene Demler
Summary: Controlling quantum matter with cavities offers new ways to study and manipulate many-body systems, particularly in unconventional or high-Tc systems. This paper proposes a scheme for coupling terahertz resonators to antiferromagnetic fluctuations in cuprate families to enhance superconductivity, and explores the underlying coupling mechanisms.
PHYSICAL REVIEW RESEARCH
(2022)
