Quantum entanglement and entropy in particle creation

Understand

We investigate the basic theoretical issues in the quantum entanglement of particle pairs created from the vacuum in a time-dependent background field or spacetime.

• Similar to entropy generation from these processes which depends on the choice of physical variables and how certain information is coarse-grained, entanglement dynamics hinges on the choice of measurable quantities and how the two parties are selected as well as the background dynamics of the field or spacetime.
• We discuss the conditions of separability of quantum states in particle creation processes and point out the differences in how the von Neumann entropy is used as a measure of entropy generation versus for entanglement dynamics.
• We show by an explicit construction that adoption of a different set of physical variables yields a different entanglement entropy.