Entanglement of a two-atom system driven by the quantum vacuum in arbitrary cavity size

We study the entanglement dynamics of two distinguishable atoms confined into a cavity and interacting with a quantum vacuum field. As a simplified model for this system, we consider two harmonic oscillators linearly coupled to a massless scalar field which are inside a spherical cavity of radius R. Through the concurrence, the entanglement dynamics for the two-atom system is discussed for a range of initial states composed of a superposition of atomic states. Our results reveal how the entanglement of the two atoms behaves through the time evolution, in a precise way, for arbitrary cavity size and for arbitrary coupling constant. All our computations are analytical and only the final step is numerical.