Testing the quantumness of gravity via a mathematical theory of quantum benchmarks

Testing the quantumness of gravity via a mathematical theory of quantum benchmarks

Seminar author:Ludovico Lami

Event date and time:09/16/2021 04:00:pm

Event location:https://us02web.zoom.us/j/84464822440?pwd=a2xQREM2ZjBQdVlyK2NkdE8zU253Zz09

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Given a system of massive quantum harmonic oscillators, how can we test whether their gravitational interaction is classical or quantum? Here we propose a general Gedankenexperiment to do so and benchmark it, i.e. we show how to determine the threshold beyond which one can claim that gravity behaves as a quantum interaction Hamiltonian instead of a classical field. The remarkable aspect of our approach is that it bypasses completely the problem of how a classical gravitational field may interact with the quantum oscillators. Using a delightfully simple trick from quantum information, we are able to give a bound that applies to all physically conceivable scenarios at once. We find that in a certain regime the best classical strategy introduces an error that grows linearly with time, with a coefficient that depends on the geometry of the system.