Scrambling dynamics and many-body chaos in a random dipolar spin model

Keles, Ahmet1,2,3; Zhao, Erhai2,3; Liu, W. Vincent1,4,5,6,7

2019-05-29

10.1103/PhysRevA.99.053620

PHYSICAL REVIEW A   影响因子和分区

2469-9926

2469-9934

Is there a quantum many-body system that scrambles information as fast as a black hole? The Sachev-Ye-Kitaev model can saturate the conjectured bound for chaos, but it requires random all-to-all couplings of Majorana fermions that are hard to realize in experiments. Here we examine a quantum spin model of randomly oriented dipoles where the spin exchange is governed by dipole-dipole interactions. The model is inspired by recent experiments on dipolar spin systems of magnetic atoms, dipolar molecules, and nitrogen-vacancy centers. We map out the phase diagram of this model by computing the energy-level statistics, spectral form factor, and out-of-time-order correlation (OTOC) functions. We find a broad regime of many-body chaos where the energy levels obey Wigner-Dyson statistics and the OTOC shows distinctive behaviors at different times: Its early-time dynamics is characterized by an exponential growth, while the approach to its saturated value at late times obeys a power law. The temperature scaling of the Lyapunov exponent lambda(L) shows that while it is well below the conjectured bound 2 pi T at high temperatures, lambda(L) approaches the bound at low temperatures and for large number of spins.

SCI ; EI

英语

其他

Overseas Collaboration Program of NSF of China - Peking University[11429402]

Optics ; Physics

Optics ; Physics, Atomic, Molecular & Chemical

WOS:000469324000005

AMER PHYSICAL SOC

20192307002552

Lyapunov methods ; Quantum theory

Atomic and Molecular Physics:931.3 ; Quantum Theory; Quantum Mechanics:931.4 ; Systems Science:961

PHYSICS

Web of Science

1.Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA
2.George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA
3.George Mason Univ, Quantum Mat Ctr, Fairfax, VA 22030 USA
4.Shanghai Jiao Tong Univ, Wilczek Quantum Ctr, Sch Phys & Astron, Shanghai 200240, Peoples R China
5.Shanghai Jiao Tong Univ, Wilczek Quantum Ctr, TD Lee Inst, Shanghai 200240, Peoples R China
6.Southern Univ Sci & Technol, Shenzhen Inst Quantum Sci & Engn, Shenzhen 518055, Peoples R China
7.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China

Keles, Ahmet,Zhao, Erhai,Liu, W. Vincent. Scrambling dynamics and many-body chaos in a random dipolar spin model[J]. PHYSICAL REVIEW A,2019,99(5).

Keles, Ahmet,Zhao, Erhai,&Liu, W. Vincent.(2019).Scrambling dynamics and many-body chaos in a random dipolar spin model.PHYSICAL REVIEW A,99(5).

Keles, Ahmet,et al."Scrambling dynamics and many-body chaos in a random dipolar spin model".PHYSICAL REVIEW A 99.5(2019).