Quantum echo dynamics in the Sherrington-Kirkpatrick model
Silvia Pappalardi, Anatoli Polkovnikov, Alessandro Silva
SciPost Phys. 9, 021 (2020) · published 19 August 2020
- doi: 10.21468/SciPostPhys.9.2.021
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Abstract
Understanding the footprints of chaos in quantum-many-body systems has been under debate for a long time. In this work, we study the echo dynamics of the Sherrington-Kirkpatrick (SK) model with transverse field under effective time reversal. We investigate numerically its quantum and semiclassical dynamics. We explore how chaotic many-body quantum physics can lead to exponential divergence of the echo of observables and we show that it is a result of three requirements: i) the collective nature of the observable, ii) a properly chosen initial state and iii) the existence of a well-defined chaotic semi-classical (large-$N$) limit. Under these conditions, the echo grows exponentially up to the Ehrenfest time, which scales logarithmically with the number of spins $N$. In this regime, the echo is well described by the semiclassical (truncated Wigner) approximation. We also discuss a short-range version of the SK model, where the Ehrenfest time does not depend on $N$ and the quantum echo shows only polynomial growth. Our findings provide new insights on scrambling and echo dynamics and how to observe it experimentally.
Cited by 17
Authors / Affiliations: mappings to Contributors and Organizations
See all Organizations.- 1 2 3 Silvia Pappalardi,
- 2 Anatoli Polkovnikov,
- 1 Alessandro Silva
- 1 Centro Internazionale di Fisica Teorica Abdus Salam / Abdus Salam International Centre for Theoretical Physics [ICTP]
- 2 Scuola Internazionale Superiore di Studi Avanzati / International School for Advanced Studies [SISSA]
- 3 Boston University [BU]