3 papers
hep-th2026
Boundary Completion of Vacuum Persistence Probability
Yu Zhou, Hai-Qing Zhang
The vacuum persistence probability, encoded in the imaginary part of the in-out effective action, is a basic measure of vacuum instability and particle production. However, its eva…
hep-th2025
On the Imaginary Part of the Effective Action in de Sitter Spacetime with Different Regularization Schemes
Yu Zhou, Hai-Qing Zhang
The imaginary part of the effective action encodes vacuum instability and particle production in the background field. Two standard approaches are commonly used to derive it: the B…
gr-qc2024
Effective Action and Gravitational Pair Production in (A)dS Spacetime
Yu Zhou, Hai-Qing Zhang
We compute the effective action for a massive scalar field in (A)dS spacetime using the Euclidean heat kernel method. We highlight that in even-dimensional dS spacetimes, the effec…