Gravitational Casimir-Polder interaction between an excited nonpointlike object and a gravitational boundary
Phys. Rev. D 112, 044017 – Published 8 August, 2025
DOI: https://doi.org/10.1103/dxzc-759t
Abstract
We explore, within the framework of linearized quantum gravity, the Casimir-Polder (CP)–like quantum gravitational interaction between an excited nonpointlike object and a gravitational Dirichlet boundary based on perturbation theory. Our result shows that, the gravitational Casimir-Polder interaction potential for an excited object decreases as in the near regime where the distance between the object and the boundary is smaller than the characteristic transition wavelength of the object, while it oscillates as in the far regime where the distance is larger than the characteristic transition wavelength, with denoting the object-boundary distance. Compared to the gravitational CP force between a ground-state object and a gravitational Dirichlet boundary, which is repulsive in both the near and far regimes, the present interaction can be either attractive or repulsive in the far zone, depending on the object-boundary distance and the transition wavelength of the object. Moreover, the far-region behavior of an excited object decays as , which is significantly slower than the dependence observed for a ground-state object. This suggests that the gravitational CP interaction can be enhanced or modulated by altering the initial state of the nonpointlike object.