**Time/Venue** Wednesday, June 8 at 2:00 pm Pacific Time in Physics South 402 via Zoom:

https://berkeley.zoom.us/j/99523499113pwd=REovb3pyam03WXQwbEhrU3dqNHZvdz09

Meeting ID: 995 2349 9113 Passcode: 600704**Host** Ehud Altman**Title**: The dynamics of quantum coherence in measurement induced phase transitions**Abstract**: The coherent superposition of quantum states is a key feature of quantum mechanics which distinguishes quantum dynamics and information from their classical counterparts.

It can be quantified by the relative entropy of coherence, and in this talk we investigate its dynamics in random hybrid circuits and its role in the protection of quantum information. We first discuss a coherence free circuit which provides a classical analog of the measurement induced phase transition, and which shows a transition in the classical channel capacity. We then investigate a circuit in which measurements dynamically change the coherence, and show how coherence dynamics can be used to control entanglement phase transitions. Using the intuition developed by studying these hybrid circuits we conclude by proving that the coherence in any local basis gives an upper bound for the quantum code distance of any stabilizer quantum error correction code. Such a bound provides a rigorous quantification of the coherence resource requirements for quantum error correction.

# QM Seminar Speaker Shane Kelly (Johannes Gutenberg-Universität Mainz) Wednesday, June 8 at 2:00 pm

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