Probing quantum many-body dynamics using subsystem Loschmidt echos
Reviewed by Pithpith:H26AGI4Popen to challenge →
read the original abstract
The Loschmidt echo - the probability of a quantum many-body system to return to its initial state following a dynamical evolution - generally contains key information about a quantum system, relevant across various scientific fields including quantum chaos, quantum many-body physics, or high-energy physics. However, it is typically exponentially small in system size, posing an outstanding challenge for experiments. Here, we experimentally investigate the subsystem Loschmidt echo, a quasi-local observable that captures key features of the Loschmidt echo while being readily accessible experimentally. Utilizing quantum gas microscopy, we study its short- and long-time dynamics. In the short-time regime, we observe a dynamical quantum phase transition arising from genuine higher-order correlations. In the long-time regime, the subsystem Loschmidt echo allows us to quantitatively determine the effective dimension and structure of the accessible Hilbert space in the thermodynamic limit. Performing these measurements in the ergodic regime and in the presence of emergent kinetic constraints, we provide direct experimental evidence for ergodicity breaking due to fragmentation of the Hilbert space. Our results establish the subsystem Loschmidt echo as a novel and powerful tool that allows paradigmatic studies of both non-equilibrium dynamics and equilibrium thermodynamics of quantum many-body systems, applicable to a broad range of quantum simulation and computing platforms.
This paper has not been read by Pith yet.
Forward citations
Cited by 15 Pith papers
-
Exact Current Fluctuations in a Tight-Binding Chain with Dephasing Noise
Exact Fredholm determinant representation for current FCS in dephasing tight-binding chain yields diffusive scaling in long-time cumulants.
-
Graph-Theoretic Detection of Hilbert Space Fragmentation
Spectral graph analysis of the Hilbert-space connectivity graph detects exact fragmentation and nearly fragmented sectors with slow leakage in the t-J model and Hubbard chain.
-
Graph-theory measures capture weak ergodicity breaking on large quantum systems
Graph-energy centrality applied to Fock-space graphs captures weak ergodicity-breaking transitions in quantum many-body systems and scales to hundreds of sites or the thermodynamic limit.
-
Dynamical preparation of U(1) quantum spin liquids in an analogue quantum simulator
Experimental realization of large-scale U(1) quantum spin liquid regions in a 2D analog quantum simulator using ultracold atoms, with evidence from Gauss-law compliance, pinch-point correlations, and many-body coheren...
-
Floquet Many-Body Cages
Floquet circuits can be built to host many-body cages that carry topological features and π-quasienergy modes, producing time-crystalline spatiotemporal order in models such as the quantum hard disk.
-
Smearing of dynamical quantum phase transitions in dissipative free-fermion systems
Dynamical quantum phase transitions in the reduced Loschmidt echo persist under purely gain or loss dissipation but are completely smeared by any combination of both channels, even when one is infinitesimal.
-
Meson spectroscopy of exotic symmetries of Ising criticality in Rydberg atom arrays
Rydberg arrays realize Ising criticality with E8 mass spectra in chains and first signatures of D8^(1)-organized bound states from interchain confinement in ladders.
-
(Non-)Traversable Quantum Phase Transitions
Proposes classifying quantum phase transitions by whether they are traversable via finite counterdiabatic driving protocols or nontraversable due to infinite geometric distance in the ground-state manifold.
-
Graph-theory measures capture weak ergodicity breaking on large quantum systems
Graph-energy centrality detects weak ergodicity-breaking transitions in large quantum many-body systems via changes in its distribution and applies to kinetically constrained models showing glassy dynamics.
-
Revealing emergent many-body phenomena by analyzing large-scale space-time records of monitored quantum systems
In a monitored dissipative spin model realizable on Rydberg simulators, free-energy functionals applied to trajectory ensembles identify dynamical features akin to hydrophobic effects in classical phase transitions.
-
Provable Quantum Advantage for Dynamical Phase Transition
Proves intractability of DQPT estimation on quantum computers but equivalence of subsystem DQPT decision to quantum circuit simulation, with quadratic speedup for critical time search.
-
Phase-Sensitive Measurements on a Fermi-Hubbard Quantum Processor
Hardware-efficient protocol for measuring complex Loschmidt echoes in a Fermi-Hubbard optical-lattice processor via quench dynamics and tailored imaginary-time pulses.
-
Dynamics of Loschmidt echoes from operator growth in noisy quantum many-body systems
Operator Loschmidt echoes in noisy unitary dynamics are equivalent to the norm of dissipative dynamics after noise averaging, exhibiting Gaussian decay for pt ≪ 1 and noise-independent exponential decay for pt ≫ 1, wi...
-
Post-Selection Probability and Fidelity of Bidirectional Teleportation
Post-selection probability and fidelity of bidirectional teleportation are expressed via the Loschmidt echo, revealing initial-state dependence of fidelity and stability of probability in integrable models.
-
Quantum simulation of out-of-equilibrium dynamics in gauge theories
The paper reviews advances in quantum simulation of out-of-equilibrium dynamics in gauge theories, covering particle production, string breaking, thermalization, and related phenomena.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.