Probing Hilbert space fragmentation using controlled dephasing

Abstract

Dynamical constraints in many-body quantum systems can lead to Hilbert space fragmentation, wherein the system's evolution is restricted to small subspaces of Hilbert space called Krylov sectors. However, unitary dynamics within individual sectors may also be slow or non-ergodic, which limits experiments' ability to measure the properties of the entire sector. We show that additional controlled dephasing reliably mixes the system within a single Krylov sector, and that simple observables can differentiate these sectors. For example, in the strongly interacting XXZ chain with dephasing, the spin imbalance between even and odd sublattices distinguishes sectors. For appropriate choices of initial states, the imbalance begins positive, decays to a negative minimum value at intermediate times, and eventually returns to zero. The minimum reflects the average imbalance of the Krylov sector associated to the initial state. We compute the size of the minimum analytically in the limit of strong interactions, and validate our results with simulations at experimentally relevant interaction strengths.

12 pages, 10 figures

References in corpus (44)

• Many-Body Physics with Ultracold Gases
• Nonequilibrium dynamics of closed interacting quantum systems
• Probing many-body dynamics on a 51-atom quantum simulator
• Many body localization and thermalization in quantum statistical mechanics
• From Quantum Chaos and Eigenstate Thermalization to Statistical Mechanics and Thermodynamics
• Many-body localization, thermalization, and entanglement
• The ITensor Software Library for Tensor Network Calculations
• Quench dynamics and relaxation in isolated integrable quantum spin chains
• A short introduction to the Lindblad Master Equation
• Eigenstate Thermalization Hypothesis
• Localization from Hilbert space shattering: from theory to physical realizations
• Local constraints can globally shatter Hilbert space: a new route to quantum information protection
• Quantum Many-Body Scars and Hilbert Space Fragmentation: A Review of Exact Results
• Ergodicity-breaking arising from Hilbert space fragmentation in dipole-conserving Hamiltonians
• Observing non-ergodicity due to kinetic constraints in tilted Fermi-Hubbard chains
• Fracton hydrodynamics
• Quantum Many-Body Scars: A Quasiparticle Perspective
• Hilbert-Space Fragmentation from Strict Confinement
• Relaxation of antiferromagnetic order in spin-1/2 chains following a quantum quench
• Anomalous Diffusion in Dipole- and Higher-Moment Conserving Systems
• Non-equilibrium dynamics of bosonic atoms in optical lattices: Decoherence of many-body states due to spontaneous emission
• Exact solution for a diffusive nonequilibrium steady state of an open quantum chain
• Aspects of non-equilibrium in classical and quantum systems: slow relaxation and glasses, dynamical large deviations, quantum non-ergodicity, and open quantum dynamics
• Dynamics of strongly interacting systems: From Fock-space fragmentation to Many-Body Localization
• Localization in fractonic random circuits
• Kinetically constrained freezing transition in a dipole-conserving system
• Influence of dephasing on many-body localization
• Quaternion, harmonic oscillator, and high-dimensional topological states
• Quantum Many-body Scars in a Landau Level on a Thin Torus
• The Folded Spin-1/2 XXZ Model: I. Diagonalisation, Jamming, and Ground State Properties
• Spectral statistics in constrained many-body quantum chaotic systems
• Transport in a disordered tight-binding chain with dephasing
• Role of interactions in a dissipative many-body localized system
• Many-body localization in a fragmented Hilbert space
• Hilbert space fragmentation in a 2D quantum spin system with subsystem symmetries
• The Folded Spin-1/2 XXZ Model: II. Thermodynamics and Hydrodynamics with a Minimal Set of Charges
• Hilbert space fragmentation and slow dynamics in particle-conserving quantum East models
• Hilbert Space Fragmentation in Open Quantum Systems
• Hilbert space shattering and dynamical freezing in the quantum Ising model
• Light scattering and dissipative dynamics of many fermionic atoms in an optical lattice
• Observation of quantum thermalization restricted to Hilbert space fragments
• Probing Hilbert Space Fragmentation with Strongly Interacting Rydberg Atoms
• Subspace restricted thermalization in a correlated-hopping model with strong Hilbert space fragmentation characterized by irreducible strings
• DanceQ: High-performance library for number-conserving bases