Proposal for measuring outoftimeordered correlators at finite temperature with coupled spin chains
Abstract
Information scrambling, which is the spread of local information through a system's manybody degrees of freedom, is an intrinsic feature of manybody dynamics. In quantum systems, the outoftimeordered correlator (OTOC) quantifies information scrambling. Motivated by experiments that have measured the OTOC at infinite temperature and a theory proposal to measure the OTOC at finite temperature using the thermofield double state, we describe a protocol to measure the OTOC in a finite temperature spin chain that is realized approximately as one half of the ground state of two moderatelysized coupled spin chains. We consider a spin Hamiltonian with particlehole symmetry, for which we show that the OTOC can be measured without needing signreversal of the Hamiltonian. We describe a protocol to mitigate errors in the estimated OTOC, arising from the finite approximation of the system to the thermofield double state. We show that our protocol is also robust to main sources of decoherence in experiments.
 Publication:

arXiv eprints
 Pub Date:
 July 2021
 arXiv:
 arXiv:2107.02196
 Bibcode:
 2021arXiv210702196S
 Keywords:

 Quantum Physics;
 Condensed Matter  Quantum Gases;
 Nonlinear Sciences  Chaotic Dynamics
 EPrint:
 17 pages, 6 figures + References + Appendix