CQuIC Seminars
Phase transitions and critical states of monitored quantum systems
Presented by Ehud Altman, UC Berkely
Generic unitary evolution of a quantum state, as affected for example by non-integrable Hamiltonian dynamics or by random gates in a quantum circuit, leads to encoding of information into highly non-local degrees of freedom, where the information becomes irretrievable. Recent work on quantum circuits began to explore how this kind of non-local encoding is affected by an external observer that can perform measurement on the quantum state as it evolves. It was found that a large system undergoes a phase transition, from a state with non local encoding, evidenced by volume law entanglement, at a small enough measurement rate to an area law state above a threshold rate. I will review how such transitions in the dynamics of quantum information can be understood in terms of effective statistical mechanics models, which describe a self organized quantum error correcting code in random circuits. I will then use these models or random circuits to predict new universal phenomena in the dynamics of quantum information in monitored systems and discuss possible tests of these predictions using quantum hardware.
3:30 pm, Thursday, February 17, 2022
Zoom,
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