A5056392319- Quantum many-body systems
- Theoretical and Computational Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Stochastic processes and statistical mechanics
- Advanced Battery Materials and Technologies
- Advancements in Battery Materials
- Topological Materials and Phenomena
- Opinion Dynamics and Social Influence
- Quantum chaos and dynamical systems
- Physics of Superconductivity and Magnetism
- Algebraic structures and combinatorial models
- Advanced Thermodynamics and Statistical Mechanics
- Quantum, superfluid, helium dynamics
- Advanced battery technologies research
- Noncommutative and Quantum Gravity Theories
- Black Holes and Theoretical Physics
- Advanced Antenna and Metasurface Technologies
- Quantum and electron transport phenomena
- Quantum Information and Cryptography
- Advanced Combinatorial Mathematics
- Antenna Design and Analysis
- Quantum Computing Algorithms and Architecture
- Magnetic properties of thin films
- Conducting polymers and applications
- Graphene research and applications
Fudan University
2009-2025
State Key Laboratory of Surface Physics
2020-2025
Centre National de la Recherche Scientifique
2015-2024
Laboratoire de Physique de l'ENS
2023-2024
École Normale Supérieure - PSL
2021-2024
Université Paris Cité
1977-2024
Université Paris Sciences et Lettres
2021-2024
Sorbonne Université
2021-2024
ShangHai JiAi Genetics & IVF Institute
2021-2024
University of Science and Technology Beijing
2014-2024
We present a hypothesis for the universal properties of operators evolving under Hamiltonian dynamics in many-body systems. The states that successive Lanczos coefficients continued fraction expansion Green's functions grow linearly with rate $\alpha$ generic systems, an extra logarithmic correction 1d. --- experimental observable governs exponential growth operator complexity sense we make precise. This even prevails beyond semiclassical or large-$N$ limits. Moreover, upper bounds large...
We study the entanglement entropy of quantum trajectories a free fermion chain under continuous monitoring local occupation numbers. propose simple theory for evolution from disentangled and highly excited initial states. It is based on generalized hydrodynamics quasi-particle pair approach to in integrable systems. test several quantitative predictions against extensive numerics find good agreement. In particular, volume law destroyed by presence arbitrarily weak measurement.
Focusing on semiclassical systems, we show that the parametrically long exponential growth of out-of-time order correlators (OTOCs), also known as scrambling, does not necessitate chaos. Indeed, scrambling can simply result from presence unstable fixed points in phase space, even a classically integrable model. We derive lower bound OTOC Lyapunov exponent, which depends only local properties such points. present several models for this is tight, i.e., dominated by dynamics around propose...
A bstract In semi-classical systems, the exponential growth of out-of-time-order correlator (OTOC) is believed to be hallmark quantum chaos. However, on several occasions, it has been argued that, even in integrable OTOC can grow exponentially due presence unstable saddle points phase space. this work, we probe such an system exhibiting saddle-dominated scrambling through Krylov complexity and associated Lanczos coefficients. realm universal operator hypothesis, demonstrate that coefficients...
We study the operator growth in open quantum systems with dephasing dissipation terms, extending Krylov complexity formalism of Phys. Rev. X 9, 041017. Our results are based on dissipative $q$-body Sachdev-Ye-Kitaev (SYK$_q$) model, governed by Markovian dynamics. introduce a notion ''operator size concentration'' which allows diagrammatic and combinatorial proof asymptotic linear behavior two sets Lanczos coefficients ($a_n$ $b_n$) large $q$ limit. corroborate semi-analytics finite $N$...
Superconductor-ferromagnet (S-F) interfaces in two-dimensional (2D) heterostructures present a unique opportunity to study the interplay between superconductivity and ferromagnetism. The realization of such nanoscale van der Waals (vdW) crystals remains largely unexplored due challenge making an atomically-sharp interface from their layered structures. Here, we build vdW ferromagnetic Josephson junction (JJ) by inserting few-layer insulator Cr2Ge2Te6 into two layers superconductor NbSe2....
We study a one-dimensional gas of hard rods trapped in harmonic potential, which breaks integrability the hard-rod interaction nonuniform way. explore consequences such broken for dynamics large number particles and find three distinct regimes: initial, chaotic, stationary. The initial regime is captured by an evolution equation phase-space distribution function. For any finite particles, this hydrodynamics down becomes chaotic after characteristic timescale determined interparticle distance...
It was recently conjectured that in generic quantum many-body systems, the spectral density of local operators has slowest high-frequency decay as permitted by locality. We show infinite-temperature version this "universal operator growth hypothesis" holds for Ising spin model $d \ge 2$ dimensions, and chaotic chain (with longitudinal transverse fields) one dimension. Moreover, disordered exhibits localization can have same thermalizing models. Our argument is statistical nature, based on...
The anomalous Hall effect (AHE) is a key transport signature revealing the topological properties of magnetic compounds. In quantum materials, classical linear dependence AHE on magnetization often breaks down, which typically ascribed to presence or electronic textures. However, complex structure these compounds may offer alternative, unexplored mechanisms. Here, we show that giant nonlinear can originate from series magnetic-field-induced Lifshitz transitions in spin-dependent band...
We consider the kinetic theory of quantum and classical Toda lattice models. A equation Bethe-Boltzmann type is derived for distribution function conserved quasiparticles. Near limit, we show that depends smoothly on Planck's constant, explicitly characterise leading corrections to behaviour. The compared with direct numerical simulations shows excellent agreement. Finally, connect approach inverse scattering method, by identifying quasiparticles spectrum Lax matrix.
The Toda chain with random initial data is studied. Of particular interest are generalized Gibbs ensembles, their averaged conserved fields, and the averages of corresponding currents. While fields well-understood, description currents has hitherto relied on collision-rate assumption. For chain, rate assumption can be investigated numerically. Here, we provide convincing evidence for validity This lends further support to idea that Euler-type equations have a structure common all integrable...
The anomalous Hall effect (AHE) is an important transport signature revealing topological properties of magnetic materials and their spin textures. Recently, MnBi2Te4 has been demonstrated to be intrinsic insulator. However, the origin its intriguing AHE behaviors remains elusive. Here, we demonstrate Berry curvature-dominated in wafer-scale films. By applying back-gate voltages, observe ambipolar conduction n–p transition ∼7-layer MnBi2Te4, where a quadratic relation between resistance...
We propose a solvable model of quantum Darwinism to encoding transitions---abrupt changes in how information spreads many-body system under unitary dynamics. consider random Clifford circuit on an expanding tree, whose input qubit is entangled with reference. The has phase, where one classical bit about the reference can be retrieved from arbitrarily small fraction output qubits, and phase such retrieval impossible. two phases are separated by mixed continuous transitions. compare exact...
Marine organic-rich shale in South China has considerable exploration potential, and the adsorption capacity a great impact on accumulation of gas. To study methane marine shale, ten samples from Lower Cambrian Qiongzhusi Formation eastern Yunnan province were investigated by organic geochemical analysis (total carbon content, thermal maturity, kerogen type), X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), low-pressure nitrogen experiments. Based...
Knowing how and why quantum systems thermalize is essential for developing technologies. A new numerical technique proposed experiment could fully explore the thermal integrable regimes in classical systems.
The quantum dynamics of spin systems with uniform all-to-all interaction are often studied in the totally symmetric space (TSS) maximal total spin. However TSS states atypical full many-body Hilbert space. In this work, we explore several aspects away from TSS, and reveal surprising features "deep space" (DHS). We study out-of-time order correlator (OTOC) infinite-temperature ensemble derive a phase-space representation DHS OTOC show that can grow super-exponentially large $N$ limit, due to...
Motivated by recent works on atom-cavity realizations of fast scramblers, and Cooper pairing in non-Fermi liquids, we study a family solvable variants the ($q=4$) Sachdev-Ye-Kitaev model which rank eigenvalue distribution coupling matrix $J_{ij,kl}$ are tuneable. When is proportional to number fermions, low temperature behavior sensitive distribution. We obtain complete classification possible liquid quantum phases. These include two previously studied phases whose fermion scaling dimension...
We present a new method for compressing matrix product operators (MPOs) which represent sums of local terms, such as Hamiltonians. Just with area law states, may be fully specified small amount information per site. Standard state (MPS) tools are ill-suited to this case, due extensive Schmidt values that coexist intensive ones, and Jordan blocks in the transfer matrix. ameliorate these issues by introducing an "almost decomposition" respects locality. Our is "$\varepsilon$-close" accuracy...
Abstract The development of spin-orbit-torque (SOT) devices has sparked considerable research interest, particularly in the quest for novel materials that exhibit high spin-to-charge conversion efficiencies effective magnetic switching. However, optimizing structure and improving efficiency necessitate theoretical insights material innovations. In this study, we employ first-principles calculations to investigate persistent spin current topological MnSb2Te4. weakly asymmetric surface states...
We introduce a family of Gross-Neveu-Yukawa models with large number fermion and boson flavors as higher dimensional generalizations the Sachdev-Ye-Kitaev model. The may be derived from local lattice couplings give rise to Lorentz invariant critical solutions in 1+1 2+1 dimensions. These imply anomalous dimensions both bosons fermions tuned by ratio flavors. In dimension solution represents stable phase, while it governs quantum phase transition. compute out time order correlators model,...
This Letter aims at showing that the observation of evaporating black holes should allow usual Hawking behavior to be distinguished from loop quantum gravity (LQG) expectations. We present a full Monte Carlo simulation evaporation in LQG and statistical tests discriminate between competing models. conclude contrarily what was commonly thought, discreteness area leads characteristic features qualify as objects could reveal footprints.
We characterize the soft modes of dynamical matrix at depinning transition, and compare it with properties Anderson model (and long--range generalizations). The density states edge spectrum displays a universal linear tail, different from Lifshitz tails. eigenvectors are instead very similar in two ensembles. focus on ground state (soft mode), which represents epicenter avalanche instabilities. expect to be localized all finite dimensions, make clear connection between its localization...