A5080950640- Quantum many-body systems
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Information and Cryptography
- Opinion Dynamics and Social Influence
- Quantum chaos and dynamical systems
- Theoretical and Computational Physics
- Optical Network Technologies
- Advanced Thermodynamics and Statistical Mechanics
- Photonic and Optical Devices
- Quantum, superfluid, helium dynamics
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Topological Materials and Phenomena
- Quantum Mechanics and Applications
- Spectroscopy and Quantum Chemical Studies
- Neural Networks and Reservoir Computing
- Complex Systems and Time Series Analysis
- Graphene research and applications
- Quantum Electrodynamics and Casimir Effect
- Quantum optics and atomic interactions
- Photonic Crystals and Applications
- Quantum Computing Algorithms and Architecture
- Advanced Photonic Communication Systems
- Research Data Management Practices
- Strong Light-Matter Interactions
Center for Astrophysics Harvard & Smithsonian
2022-2025
Harvard University Press
2021-2025
Harvard University
2022-2024
University of Michigan
2016-2023
National High Magnetic Field Laboratory
2020
Michigan United
2017-2018
Aalto University
2017
Istanbul Technical University
2015
The spectral form factor (SFF) captures universal fluctuations as signatures of quantum chaos, and has been instrumental in advancing multiple frontiers physics including the studies black holes many-body systems. measurement SFF systems is however challenging due to difficulty resolving level spacings that become exponentially small with increasing system size. Here, we utilize random toolbox perform a direct experimental SFF, hence probe presence or absence chaos on superconducting...
Abstract In quantum chaotic systems, the spectral form factor (SFF), defined as Fourier transform of two-level correlation function, is known to follow random matrix theory (RMT), namely a ‘ramp’ followed by ‘plateau’ in late times. Recently, generic early-time deviation from RMT, so-called ‘bump’, was shown exist circuits toy models for many-body systems. We demonstrate existence ‘bump-ramp-plateau’ behavior SFF number paradigmatic and stroboscopically-driven 1D cold-atom models: spinless...
Quantum many-body scars consist of a few low-entropy eigenstates in an otherwise chaotic spectrum, and can weakly break ergodicity resulting robust oscillatory dynamics. The notion quantum follows the original single-particle introduced within context billiards, where scarring manifests form eigenstate concentrating around underlying classical unstable periodic orbit. A direct connection between these notions remains outstanding problem. Here, we study spinor condensate that, owing to its...
We elucidate the relation between out-of-time-order correlators (OTOCs) and quantum phase transitions via analytically studying OTOC dynamics in a degenerate spectrum. Our method points to key ingredients dynamically detect phases for wide range of explains existing numerical results literature. apply our critical model, XXZ model that numerically confirms predictions.
Ergodicity of quantum dynamics is often defined through statistical properties energy eigenstates, as exemplified by Berry's conjecture in single-particle chaos and the eigenstate thermalization hypothesis many-body settings. In this work, we investigate whether systems can exhibit a stronger form ergodicity, wherein any time-evolved state uniformly visits entire Hilbert space over time. We call such phenomenon complete Hilbert-space ergodicity (CHSE), which more akin to intuitive notion an...
In this paper, we address the question: To what extent is quantum state preparation of multiatom clusters (before they are injected into microwave cavity) instrumental for determining not only kind machine may operate, but also quantitative bounds its performance? Figuratively speaking, if cluster “crude oil”, question is: Which refining process that can deliver a “gasoline” with “specific octane”? We classify coherences or correlations among atoms according to their ability serve as: (i)...
A dynamical quantum phase transition can be characterized by a nonanalytic change in the quench dynamics when parameter governing Hamiltonian is varied. Such typically only shows up long-time for extensive systems with short-range couplings. We analyze model of spin-1 particles effectively infinite-range couplings and demonstrate that this system occurs local observables short-time durations even large size. experimentally realize observe an antiferromagnetic spinor Bose-Einstein condensate...
We show that the temperature of a cavity field can be drastically varied by its interaction with suitably-entangled atom pairs (dimers) traversing under realistic atomic decoherence. To this end we resort to hitherto untapped resource naturally entangled dimers whose state simply controlled via molecular dissociation, collisions forming dimer, or unstable such as positronium. Depending on chosen cavity-field mode driven steady-state is either much lower higher than ambient temperature,...
The early-time dynamics of many-body quantum chaotic systems is typically considered non-universal due to the divergence from predictions random matrix theory. eigenstate stacking theorem, on other hand, asserts uniformity in a phase space for cumulative probability density eigenstates that fall within sufficiently large energy window, opening route universality early times. This fact must hold even systems. Here, we study spinor Bose-Einstein condensate, whose scar has recently been...
Thermalization of isolated quantum systems is a long-standing fundamental problem where different mechanisms are proposed over time. We contribute to this discussion by classifying the diverse quench-dynamical behaviors spin-1 Bose-Einstein condensates, which includes well-defined collapse and revivals, thermalization, certain special cases. These cases either nonthermal equilibration with no revival but even though system has finite degrees freedom or revival. Given that some integrable...
We report a numerical observation where the infinite-temperature out-of-time-order correlators (OTOCs) directly probe quantum phase transitions at zero temperature, in contrast to common intuition low-energy effects are washed away by strong thermal fluctuations high temperature. By comparing simulations with exact analytic results, we determine that this phenomenon has topological origin and is highly generic, as long underlying system can be mapped 1D Majorana chain. Using basis, show...
Strong interactions between electrons occupying bands of opposite (or like) topological quantum numbers (Chern$=\pm1$), and with flat dispersion, are studied by using lowest Landau level (LLL) wavefunctions. More precisely, we determine the ground states for two scenarios at half-filling: (i) LLL's sign magnetic field, therefore Chern number; (ii) same field. In first scenario -- which argue to be a toy model inspired chirally symmetric continuum twisted bilayer graphene Kramer pairs, thus...
Out-of-time-order correlators (OTOC), recently being the center of discussion on quantum chaos, are a tool to understand information scrambling in different phases many-body systems. We propose disordered ladder spin model, XX-ladder, which can be designed scalable cold atom setup detect OTOC with novel sign reversal protocol for evolution backward time. study both clean and limits XX-ladder characterize (ergodic-MBL) model based decay properties OTOCs. Emergent effective lightcone shows...
Recently, single-site observables have been shown to be useful for probing critical slowing down in sudden quench dynamics [Da\ifmmode \breve{g}\else \u{g}\fi{} et al., Phys. Rev. B 107, L121113 (2023)]. Here, we demonstrate the potential of magnetization as a probe quantum phase transitions integrable and nonintegrable transverse-field Ising chains (TFIC). We analytically prove requirement zero modes quasistationary regime emerge at site near edge, show how this gives rise nonanalytic...
Dynamical detection of quantum phases and phase transitions (QPTs) in quenched systems with experimentally convenient initial states is a topic interest from both theoretical experimental perspectives. Quenched polarized states, longitudinal magnetization decays exponentially to zero time for the short-range transverse-field Ising model hence has featureless steady state regime, which prevents it exhibiting dynamical type I. In this paper, we ask whether transient regimes such nonequilibrium...
We reveal a prethermal dynamical regime upon suddenly quenching to the vicinity of quantum phase transition in time evolution one-dimensional spin chains. The is analytically found be self-similar and its duration governed by ground-state energy gap. Based on analytical insights numerical evidence, we show that this universally exists independently location probe site, presence weak interactions, or initial state. resulting dynamics leads an out-of-equilibrium scaling function order...
Results are presented for Floquet systems in two spatial dimensions where the driving breaks an effective time reversal symmetry. The protocol also induces flat bands that correspond to anomalous phases Chern number is zero and yet chiral edge modes exist. Analytic expressions modes, Berry curvature, orbital magnetization derived bands. static Haldane model parameters when flat. of same shown give rise insulators as well phases. these different topological found be enhanced at half filling...
The spectral form factor (SFF) captures universal fluctuations as signatures of quantum chaos, and has been instrumental in advancing multiple frontiers physics including the studies black holes many-body systems. However, measurement SFF systems is challenging due to difficulty resolving level spacings that become exponentially small with increasing system size. Here we experimentally measure probe presence or absence chaos using a superconducting processor randomized protocol. For Floquet...
We introduce a magnetic-flux-tunable phase shifter for propagating microwave photons, based on three equidistant superconducting quantum interference devices (SQUIDs) transmission line. experimentally implement the and demonstrate that it produces broad range of shifts full within experimental uncertainty. Together with previously demonstrated beam splitters, this can be utilized to arbitrary single-qubit gates qubits photons. These results complement previous demonstrations on-demand...
Meandering waveguide distributed feedback structures are introduced as novel integrated photonic lightwave circuit elements, and analyzed in the frequency domain by transfer matrix method. The directional coupling of electromagnetic field occurs at meander points. meandering loop mirror is building block all waveguide-based elements. simplest uncoupled structure exhibits Rabi splitting transmittance spectrum. symmetric antisymmetric coupled geometries can be utilized bandpass, Fano, or...
The devices that are variations of inter-and intracoupled meandering optical waveguides proposed as the lightwave circuit elements exhibit distributed feedback. A preliminary transfer matrix method analysis is applied in frequency domain, taking coupling purely directional and with constant coefficient on geometrically symmetric anti-symmetric devices. loop mirror building block all waveguide based elements. simplest uncoupled feedback structure exhibits Rabi splitting transmittance...
Unstable periodic orbits (UPOs) play a key role in the theory of chaos, constituting "skeleton" classical chaotic systems and "scarring" eigenstates corresponding quantum system. Recently, nonthermal many-body embedded an otherwise thermal spectrum have been identified as generalization scars. The latter, however, are not clearly associated to phase space, connection between single- notions scars remains therefore incomplete. Here, we find first originating from UPOs space. Remarkably, these...