We study the joint probability distribution function of the work and the change of photon number of the nonequilibrium process of driving the electromagnetic (EM) field in a three-dimensional cavity with an oscillating boundary. The system is initially prepared in a grand-canonical equilibrium state and we obtain the analytical expressions of the characteristic functions of work distributions in the single-resonance and multiple-resonance conditions. Our study demonstrates the validity of the fluctuation theorems of the grand-canonical ensemble in nonequilibrium processes with particle creation and annihilation. In addition, our work illustrates that, in the high-temperature limit, the work done on the quantized EM field approaches its classical counterpart, while in the low-temperature limit, similar to Casimir effect, it differs significantly from its classical counterpart.

• Received 31 January 2019

DOI:https://doi.org/10.1103/PhysRevA.99.052508