Dynamics in the presence of local symmetry-breaking impurities
arXiv:2503.14608 · doi:10.1103/p1cm-9z8n
Abstract
Continuous symmetries lead to universal slow relaxation of correlation functions in quantum many-body systems. In this work, we study how local symmetry-breaking impurities affect the dynamics of these correlation functions using Brownian quantum circuits, which we expect to apply to generic non-integrable systems with the same symmetries. While explicitly breaking the symmetry is generally expected to lead to eventual restoration of full ergodicity, we find that approximately conserved quantities that survive under such circumstances can still induce slow relaxation. This can be understood using a super-Hamiltonian formulation, where low-lying excitations determine the late-time dynamics and exact ground states correspond to conserved quantities. We show that in one dimension, symmetry-breaking impurities modify diffusive and subdiffusive behaviors associated with U and dipole conservation at late-times, e.g., by increasing power-law decay exponents of the decay of autocorrelation functions. This stems from the fact that for these symmetries, impurities are relevant in the renormalization group sense, e.g., bulk impurities effectively disconnect the system, completely modifying both temporal and spatial correlations. On the other hand, for an impurity that disrupts strong Hilbert space fragmentation, the super-Hamiltonian only acquires an exponentially small gap, leading to prethermal plateaus in autocorrelation functions which extend for times that scale exponentially with the distance to the impurity. Overall, our approach systematically characterizes how symmetry breaking impurities affect relaxation dynamics in symmetric systems.
References in corpus (50)
- Thermalization and its mechanism for generic isolated quantum systems
- Reference frames, superselection rules, and quantum information
- Quantum Many-Body Scars and Weak Breaking of Ergodicity
- Quantum Many-Body Scars and Hilbert Space Fragmentation: A Review of Exact Results
- Chaos, Complexity, and Random Matrices
- Fracton hydrodynamics
- Quantum Many-Body Scars: A Quasiparticle Perspective
- Anomalous Diffusion in Dipole- and Higher-Moment Conserving Systems
- Kinetically constrained freezing transition in a dipole-conserving system
- Enlarged symmetry algebras of spin chains, loop models, and S-matrices
- Influence matrix approach to many-body Floquet dynamics
- Multipole conservation laws and subdiffusion in any dimension
- Spectral statistics in constrained many-body quantum chaotic systems
- Minimal model for Hilbert space fragmentation with local constraints
- Real time evolution of Anderson impurity models via tensor network influence functionals
- Hilbert space fragmentation in a 2D quantum spin system with subsystem symmetries
- Non-equilibrium quantum impurity problems via matrix-product states in the temporal domain
- Constructing Tensor Network Influence Functionals for General Quantum Dynamics
- Hilbert space fragmentation and slow dynamics in particle-conserving quantum East models
- Goldstone bosons and fluctuating hydrodynamics with dipole and momentum conservation
- Hidden quasiconservation laws in fracton hydrodynamics
- Unifying Emergent Hydrodynamics and Lindbladian Low Energy Spectra across Symmetries, Constraints, and Long-Range Interactions
- Hilbert Space Fragmentation in Open Quantum Systems
- Universal subdiffusion in strongly tilted many-body systems
- From Symmetries to Commutant Algebras in Standard Hamiltonians
- Dynamics of Fluctuations in Quantum Simple Exclusion Processes
- Scrambling of Algebras in Open Quantum Systems
- Exact solution for the filling-induced thermalization transition in a 1D fracton system
- Low-energy potential scattering in two and three dimensions
- Hydrodynamics as the effective field theory of strong-to-weak spontaneous symmetry breaking
- Exhaustive Characterization of Quantum Many-Body Scars using Commutant Algebras
- Note on entropy dynamics in the Brownian SYK model
- Ergodicity breaking provably robust to arbitrary perturbations
- Asymptotic Quantum Many-Body Scars
- Prethermalization and the local robustness of gapped systems
- Hydrodynamics in long-range interacting systems with center-of-mass conservation
- Numerical Methods for Detecting Symmetries and Commutant Algebras
- Strong Hilbert space fragmentation via emergent quantum drums in two dimensions
- Revisiting the Mazur bound and the Suzuki equality
- Hydrodynamic effective field theories with discrete rotational symmetry
- Symmetries as Ground States of Local Superoperators: Hydrodynamic Implications
- Topologically stable ergodicity breaking from emergent higher-form symmetries in generalized quantum loop models
- Glassy word problems: ultraslow relaxation, Hilbert space jamming, and computational complexity
- Highly entangled stationary states from strong symmetries
- Spacetime picture for entanglement generation in noisy fermion chains
- Stabilizer Scars
- Robust Hilbert space fragmentation in group-valued loop models
- Quantum Fragmentation in the Extended Quantum Breakdown Model
- Phase transitions in sampling and error correction in local Brownian circuits
- Bipartite Sachdev-Ye Models with Read-Saleur Symmetries