Proposal for measuring out-of-time-ordered correlators at finite temperature with coupled spin chains

Information scrambling, which is the spread of local information through a system's many-body degrees freedom, an intrinsic feature dynamics. In quantum systems, out-of-time-ordered correlator (OTOC) quantifies scrambling. Motivated by experiments that have measured OTOC at infinite temperature and theory proposal to measure finite using thermofield double state, we describe protocol in spin chain realized approximately as one half ground state two moderately-sized coupled chains. We consider Hamiltonian with particle-hole symmetry, for show can be without needing sign-reversal Hamiltonian. mitigate errors estimated OTOC, arising from approximation system state. our also robust main sources decoherence experiments.