Speaker: 
Sam Garratt - UC Berkeley

Title: 
Measurements conspire nonlocally to restructure critical quantum states

Abstract:
 I will discuss the effects of local measurements on critical quantum ground states. In critical states there are algebraic correlations between local observables and, as a consequence, local measurements can have highly nonlocal effects. This raises the possibility for a new class of collective phenomenon arising from the conspiracy of commuting measurements alone. In certain scenarios the post-measurement state has qualitatively different correlations to the original ground state, while in others the original correlations are robust, and I will discuss a sharp transition between these two regimes. Because there is no dynamics in the problem this behavior is robust to local decoherence, although a post-selection problem poses a barrier to their direct observation. I will show that resource-efficient probes are instead to be found in cross-correlations between experimental measurement results and simulations on classical computers.

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QuCoLiMa Talks are regular seminars of the collaborative research center TRR 306 QuCoLiMa (Quantum Cooperativity of Light and Matter), where (external) experts are invited to present their work.

More information at www.qucolima.de/talks