An interesting talk on quantum correlations and how they relate to quantum computing.

Abstract:

Quantum correlations in time have a surprisingly similar structure as spatial quantum correlations, formally related via the Choi-Jamiolkowski isomorphism. As a consequence, multi-time processes are endowed with the same richness as many-body physics, including temporal entanglement and well-defined causal structures. We dub this as ‘many-time physics’ and show how it naturally arises in the contexts of noisy quantum dynamics of device and more general non-Markovian open quantum systems. We develop a family of tools for accessing many-time physics on quantum information processors, which are then demonstrated on IBM Quantum devices. We explore the structure of temporal correlations, and show how they can be manipulated either to produce a more complex process, or to remove noise in a device. At first, we consider short-range microscopic properties, such as genuine multi-time entanglement and estimators for non-Markovian memory. Then, adapting classical shadow tomography to the temporal domain, we access macroscopic process features like long-range correlations and a tensor network representation of a 20-step process. We show that we can validate our model by accurately predicting the outcomes of mid-circuit measurements for random circuit sequences. Our techniques are pertinent to generic quantum stochastic dynamical processes, with a scope ranging across condensed matter physics, quantum biology, and in-depth diagnostics of NISQ era quantum devices.

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