CMSA General Relativity Seminar: Real-time observables in horizon thermodynamics

Euclidean black hole 1-loop determinants have recently been shown to compute a renormalized thermal canonical partition function for free fields in Lorentzian signature. A key ingredient is a 'quasinormal mode (QNM) character', whose Fourier transform equals the renormalized spectral density of the single-particle Hamiltonian. Using a static patch in de Sitter space as an example, in this talk, I will offer new perspectives on the QNM character, including its connection with the local density of states for the single-particle quantum mechanical problem associated with the Klein-Gordon equation, and its direct relationships with (thermal) correlators of the free fields. I will discuss how these considerations might point toward a generalization to interacting theories.