Decoherence due to Thermal Gravitons: from Cosmological Horizons to Qubits in Hardware

Spacetime that undergoes accelerated expansion is filled with thermal radiation into all particle species. This includes gravitons, which are of particular interest because they cannot be screened. As a result, thermal gravitons provide an unavoidable source of decoherence. Although the associated decoherence rate is extremely small, it proceeds on cosmological timescales comparable to other processes, most notably false vacuum decay. How these two phenomena interact is a subtle question. Does gravitational decoherence stabilize the false vacuum in a quantum Zeno-like way, or does it induce vacuum decay via measurement? In addition to discussing the underlying physics, I will also discuss prospects of answering the question via quantum simulation and present work in progress in this direction.