Entanglement of Harmonic Systems in Squeezed States
arXiv:2304.04241 · doi:10.1007/JHEP10(2023)039
Abstract
The entanglement entropy of a free scalar field in its ground state is dominated by an area law term. It is noteworthy, however, that the study of entanglement in scalar field theory has not advanced far beyond the ground state. In this paper, we extend the study of entanglement of harmonic systems, which include free scalar field theory as a continuum limit, to the case of the most general Gaussian states, namely the squeezed states. We find the eigenstates and the spectrum of the reduced density matrix and we calculate the entanglement entropy. Finally, we apply our method to free scalar field theory in 1+1 dimensions and show that, for very squeezed states, the entanglement entropy is dominated by a volume term, unlike the ground-state case. Even though the state of the system is time-dependent in a non-trivial manner, this volume term is time-independent. We expect this behaviour to hold in higher dimensions as well, as it emerges in a large-squeezing expansion of the entanglement entropy for a general harmonic system.
44 pages + 29 pages appendix, 13 figures. v2: version published in JHEP
References in corpus (3)
Cited by in corpus (10)
- Real-space quantum-to-classical transition of time dependent background fluctuations
- Entanglement in Cosmology
- Modular Hamiltonian for de Sitter diamonds
- Distinguishing cosmological models through quantum signatures of primordial perturbations
- Evolution of capacity of entanglement and modular entropy in harmonic chains and scalar fields
- Entanglement Entropy of a Scalar Field in a Squeezed State
- Amplifying quantum discord during inflationary magnetogenesis through violation of parity
- Entanglement entropy evolution during gravitational collapse
- Relative entropy of single-mode squeezed states in Quantum Field Theory
- The area and volume laws for entanglement of scalar fields in flat and cosmological spacetimes