Measuring temporal entropies in experiments

We propose a novel experimental protocol to measure generalized temporal entropies in many-body quantum systems. Our approach involves using local operators as probes to characterize the out-of-equilibrium dynamics induced by a geometric double quench on a replicated system. Such protocol mimics the path-integral on the corresponding Riemann surface encoding generalized temporal entanglement. We present the results of tensor network simulations of one-dimensional systems which validate the protocol and demonstrate the experimental feasibility of measuring generalized temporal entropies, and we outline the experimental requirements for implementing these quenches using state-of-the-art quantum simulators. Therefore, our results provide a physical interpretation of the meaning of generalized temporal entropies. Furthermore, they reveal that the dynamics induced on two replicas of the Ising model in a transverse field differ qualitatively from the ones of its non-integrable extension, suggesting that generalized temporal entropies can be used as a tool for identifying different dynamical classes in quantum systems.

💡 Research Summary

The manuscript introduces a concrete experimental scheme for measuring generalized temporal entropies—specifically, temporal Rényi entropies—in many‑body quantum systems. The authors start by defining temporal entropies through a path‑integral picture in which a cut is made along the time direction rather than the spatial direction. This cut produces two “temporal states” (left and right influence functionals) that live on the horizontal legs of a matrix‑product‑operator (MPO) representation of the evolution. By partially contracting these states one obtains a family of reduced transition matrices τ_O(t). The traces of powers of τ_O(t) define the temporal Rényi entropies S_α(t)= (1‑1/α) log Tr