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Quantum spin systems with emergent de Sitter quasinormal modes

Speaker
Klaas Parmentier
Date
Mon November 4th 2024, 2:00 - 3:30pm
Affiliation
Columbia University
Event Sponsor
Stanford Institute for Theoretical Physics
Location
Varian 355

Klaas Parmentier

Resonances are as fundamental for the quantum description of unstable systems as energy eigenstates are for stable systems. In de Sitter space, these resonances, or quasinormal modes, organize quantum corrections to the entropy, which makes them a natural quantity to try and match from the microscopic side. However, with a finite number of degrees of freedom, these exponentially decaying modes cannot really exist as eigenfunctions of a Hermitian Hamiltonian. Nevertheless, there exist simple spin systems whose spectrum converges in the large-spin limit to that of a particle in de Sitter. The quasinormal modes are emergent in the sense that they govern the macroscopic effective dynamics of the spin system with increasing accuracy.