Weak ergodicity breaking from quantum many-body scars

By C. J. Turner, A. Michailidis, D. Abanin, Maksym Serbyn, Z. Papi'c. Nature Physics, 2017

1,024 citations recorded by the source corpus.

The thermodynamic description of many-particle systems rests on the assumption of ergodicity, the ability of a system to explore all allowed configurations in the phase space. Recent studies on many-body localization have revealed the existence of systems that strongly violate ergodicity in the presence of quenched disorder. Here, we demonstrate that ergodicity can be weakly broken by a different mechanism, arising from the presence of special eigenstates in the many-body spectrum that are reminiscent of quantum scars in chaotic non-interacting systems. In the single-particle case, quantum scars correspond to wavefunctions that concentrate in the vicinity of unstable periodic classical trajectories. We show that many-body scars appear in the Fibonacci chain, a model with a constrained local Hilbert space that has recently been experimentally realized in a Rydberg-atom quantum simulator. The quantum scarred eigenstates are embedded throughout the otherwise thermalizing many-body spectrum but lead to direct experimental signatures, as we show for periodic recurrences that reproduce those observed in the experiment. Our results suggest that scarred many-body bands give rise to a new universality class of quantum dynamics, opening up opportunities for the creation of novel states with long-lived coherence in systems that are now experimentally realizable. Ergodicity can be strongly broken by integrable or many-body localized systems. A new form of weak ergodicity breaking is shown to arise from the presence of special eigenstates in the many-body spectrum akin to quantum scars in chaotic systems.

Subfields: Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/b0fa85ed0b15acfa9a4b8039b2e3cee38119487b

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Citations in the corpus

Quantum computing with neutral atoms (2020, background): “It can be used to introduce controllable disorder, which is known to dramatically influence the behaviour of many-body systems [42, 43, 44, 45].”
Hilbert Space Fragmentation and Commutant Algebras (2021, background): “Nevertheless, quantum scars have a striking impact on the dynamics of particular initial states including in systems with experimental relevance, as seen in Rydberg atom experiments [9, 10].”
Statistical localization: From strong fragmentation to strong edge modes (2019, background): “[40] CJ Turner, AA Michailidis, Dmitry Abanin, Maksym Serbyn, and Zlatko Papić, “Weak ergodicity breaking from quantum many-body scars,” Nature Physics 14 (2018), 10.”
A quantum processor based on coherent transport of entangled atom arrays (2021, neutral): “c, Numerical simulations of the single-site Renyi entropy on two adjacent sites in the idealized ‘PXP’ model of perfect nearest-neighbor blockade [14].”
Quantum simulation of fundamental particles and forces (2023, background): “…theories [114], and a better understanding of phenomena such as the slow or potential lack of thermalization of quantum many-body “scar” states [250, 251], and dynamical quantum phase transitions in non-equilibrium settings [252–255], and their prevalence in gauge theories [256– 263], have…”
Quantum simulation and computing with Rydberg-interacting qubits (2020, background): “This model and its variants have been theoretically studied in 1D 225,230–232 and more recently 2D on diﬀerent lattices 233,234 and found to exhibit liquid like ground states 230 , interacting Fi-bonacci anyons 231 and quantum scars (particular states that do not thermalize) 225,229,232 and…”
Observation of many-body scarring in a Bose-Hubbard quantum simulator (2022, background): “In the PXP model, the initial states which lead to pronounced quantum revivals are the two states with the maximal number of excitations: the Néel states, |•◦•◦· · ·•◦〉 and |◦•◦•· · ·◦•〉 [23,31].”