A5035971150- Quantum many-body systems
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- Graphene research and applications
- Cold Atom Physics and Bose-Einstein Condensates
- 2D Materials and Applications
- Black Holes and Theoretical Physics
- Quantum Chromodynamics and Particle Interactions
- Quantum Mechanics and Applications
- Theoretical and Computational Physics
- Quantum, superfluid, helium dynamics
- Algebraic structures and combinatorial models
- Quantum chaos and dynamical systems
- Magneto-Optical Properties and Applications
- Quantum Information and Cryptography
- Molecular spectroscopy and chirality
- Atomic and Subatomic Physics Research
- Superconductivity in MgB2 and Alloys
- Magnetic properties of thin films
- Topological and Geometric Data Analysis
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Physical and Chemical Molecular Interactions
- Spectroscopy and Quantum Chemical Studies
Pennsylvania State University
2019-2025
University of Illinois Urbana-Champaign
2022
Massachusetts Institute of Technology
2018-2021
Harvard University Press
2020
Princeton University
2020
University of California, Santa Barbara
2014-2018
Xidian University
2014
Texas A&M University
2011
Magic angle twisted bilayer graphene (MATBG) is an exciting new system for flat electronic bands and correlated physics. However, heterostrains are ubiquitous in the TBG samples, their role on properties has not been clear. Here, authors show that generically broaden MATBG. This explains many puzzling results from transport scanning tunneling spectroscopy experiments. Furthermore, one can utilize heterostrain to engineer highly flexible moir\'e transition metal dichalcogenides, suggesting...
We investigate the moiré band structures and strong correlation effects in twisted bilayer MoTe[Formula: see text] for a wide range of twist angles, employing combination various techniques. Using large-scale first-principles calculations, we pinpoint realistic continuum modeling parameters, subsequently deriving maximally localized Wannier functions top three bands. Simplifying our model with reasonable assumptions, obtain minimal two-band model, encompassing Coulomb repulsion, correlated...
Symmetry in mixed quantum states can manifest two distinct forms: , where each individual pure state the ensemble is symmetric with same charge, and which applies only to entire ensemble. This paper explores a novel type of spontaneous symmetry breaking (SSB) strong broken weak one. While SSB measured by long-ranged two-point correlation function, strong-to-weak (SWSSB) . We prove that SWSSB universal property mixed-state phases, sense phenomenon robust against low-depth local channels. also...
We study a series of perturbations on the Sachdev-Ye-Kitaev (SYK) model. show that maximal chaotic non-Fermi-liquid phase described by ordinary $q=4$ SYK model has marginally relevant or irrelevant (depending sign coupling constants) four-fermion allowed symmetry. Changing one these leads to continuous chaotic-nonchaotic quantum transition system accompanied spontaneous time-reversal symmetry breaking. Starting with ${\mathrm{SYK}}_{q}$ $q$-fermion interaction, similar can lead new fixed...
In this paper we systematically classify and describe bosonic symmetry protected topological (SPT) phases in all physical spatial dimensions using semiclassical nonlinear Sigma model (NLSM) field theories. All the SPT on a $d-$dimensional lattice discussed can be described by same NLSM, which is an O(d+2) NLSM $(d+1)-$dimensional space-time, with $\Theta-$term. The Landau order parameter unit length constraint. classification of based their NLSMs consistent more mathematical group...
In this work we explore the interplay between global symmetry and mobility of quasiparticle excitations. We show that fractonic matter naturally appears in a three dimensional U(1) gauge theory, enriched by translational symmetries, via mechanism anyonic spin-orbital coupling. develop systematic understanding such symmetry-enforced restrictions terms classification theories symmetries. provide unified construction these phases gauging layered symmetry-protected topological phases.
We demonstrate the following conclusion: If $|\Psi\rangle$ is a $1d$ or $2d$ nontrivial short range entangled state, and $|\Omega \rangle$ trivial disordered state defined on same Hilbert space, then quantity (so called strange correlator) $C(r, r^\prime) = \frac{\langle \Omega|\phi(r) \phi(r^\prime) | \Psi\rangle}{\langle \Omega| \Psi\rangle}$ either saturates to constant decays as power-law in limit $|r - r^\prime| \rightarrow +\infty$, even though both $| \Omega\rangle$ \Psi\rangle$ are...
We ask whether a local Hamiltonian with featureless (fully gapped and nondegenerate) ground state could exist in certain quantum spin systems. address this question by mapping the vicinity of critical point (or gapless phase) $d$-dimensional system under study to boundary $(d+1)$-dimensional bulk state, lattice symmetry acts as an onsite field theory that describes both selected corresponding bulk. If action is nonanomalous, i.e., trivial instead bosonic symmetry-protected topological (SPT)...
The authors deal with the fundamental problem of a rigorous classification quantum topological phases. Here, they extend to realm interacting fermions in two dimensions techniques, developed for bosons, whereby introduce extrinsic defects carrying symmetry fluxes into phase. result is complete symmetry-protected phases dimensions. In addition, fermion systems time-reversal also developed. advances, reported here, are immediately relevant selection reliable candidates topologically protected...
This paper uncovers the properties of topological defects in valence plaquette solid phases on square and cubic lattices show that order parameter, addition to possessing non-trivial quantum numbers, exhibit fracton behavior with special mobility constraints
We show that a class of $\mathcal{PT}$ symmetric non-Hermitian Hamiltonians realizing the Yang-Lee edge singularity exhibits an entanglement transition in long-time steady state evolved under Hamiltonian. Such is induced by level crossing triggered critical point associated with and hence first-order nature. At transition, entropy jumps discontinuously from volume-law to area-law scaling. exemplify this mechanism using one-dimensional transverse field Ising model additional imaginary fields,...
Abstract Artificial moiré superlattices in 2 d van der Waals heterostructures are a new venue for realizing and controlling correlated electronic phenomena. Recently, twisted bilayer WSe emerged as robust system hosting insulator at half-filling over range of twist angle. In this work, we present theory insulating state an excitonic density wave due to intervalley electron–hole pairing. We show that exciton condensation is strongly enhanced by Hove singularity near the Fermi level. Our...
We propose a $d-$dimensional interacting Majorana fermion model with quenched disorder, which gives us continuous quantum phase transition between diffusive thermal metal finite entropy density to an insulator zero density. This is based on coupled Sachdev-Ye-Kitaev clusters, and hence has controlled large-$N$ limit. The metal-insulator accompanied by spontaneous time-reversal symmetry breaking. perform calculations show that the diffusion constant jumps discontinuously at transition, while...
We show that the out-of-time-order correlation (OTOC) $\ensuremath{\langle}W{(t)}^{\ifmmode\dagger\else\textdagger\fi{}}V{(0)}^{\ifmmode\dagger\else\textdagger\fi{}}W(t)V(0)\ensuremath{\rangle}$ in many-body localized (MBL) and marginal MBL systems can be efficiently calculated by spectrum bifurcation renormalization group (SBRG). find systems, scrambling time ${t}_{\text{scr}}$ follows a stretched exponential scaling with distance ${d}_{WV}$ between operators $W$ $V$:...
The presence of topological flat minibands in moiré materials provides an opportunity to explore the interplay between topology and correlation. In this work, we study insulator films with two hybridized surface states under a superlattice potential created by two-dimensional insulating materials. We show lowest conduction (highest valence) Kramers' pair can be Z2 non-trivial when minima (maxima) approximately form hexagonal lattice six-fold rotation symmetry. Coulomb interaction drive into...
We first propose a topological term that captures the "intertwinement" between standard "$\sqrt{3} \times \sqrt{3}$" antiferromagnetic order (or so-called 120$^\circ$ state) and "$\sqrt{12}\times \sqrt{12}$" valence solid bond (VBS) for spin-1/2 systems on triangular lattice. Then using controlled renormalization group calculation, we demonstrate there exists an unfine-tuned direct continuous deconfined quantum critical point (dQCP) two ordered phases mentioned above. This dQCP is described...
Continuous quantum phase transitions that are beyond the conventional paradigm of fluctuations a symmetry breaking order parameter challenging for theory. These often involve emergent deconfined gauge fields at critical points as demonstrated in 2+1-dimensions. Examples include magnetism well those between Symmetry Protected Topological phases. In this paper, we present several examples Deconfined Quantum Critical Points (DQCP) phases 3+1-D both bosonic and fermionic systems. Some theories...
We propose a series of simple $2d$ lattice interacting fermion models that we demonstrate at low energy describe bosonic symmetry protected topological (SPT) states and quantum phase transitions between them. This is because due to interaction the fermions are gapped both boundary SPT bulk transition, thus these can be described completely by degrees freedom. show Sp($N$) principal chiral model with $\Theta$-term, whose Wess-Zumino-Witten term level-1. The transition in tuned particular...
The experimental observation of superconductivity in doped semimetals and semiconductors, where the Fermi energy is comparable to or smaller than characteristic phonon frequencies, not captured by conventional theory. In this paper, we propose a mechanism for ultralow-density three-dimensional Dirac materials based on proximity ferroelectric quantum critical point. We derive low-energy theory that takes into account both strong Coulomb interaction direct coupling between electrons soft...
In this work, we present a collection of three-dimensional higher-order symmetry-protected topological phases (HOSPTs) with gapless hinge modes that exist only in strongly interacting systems subject to subsystem symmetry constraints. We use coupled wire construction generate three families microscopic lattice models: insulators helical modes, superconductors chiral Majorana and fractionalized carry fractional charge. particular, these HOSPTs do not require spatial protection, but are...
The notion of higher-order topological phases can have interesting generalizations to systems with subsystem symmetries that exhibit fractonic dynamics for charged excitations. In this work, we systematically study the protected by a combination and ordinary global in two three-dimensional interacting boson systems, some fermionic examples.
In this paper we construct bosonic short range entangled (SRE) states in all spatial dimensions by coupling a $Z_2$ gauge field to fermionic SRE with the same symmetries, and driving its confined phase. We demonstrate that approach allows us many examples of states, previous descriptions such as semiclassical nonlinear sigma model theory Chern-Simons can be derived using states.