Abstract
We compute the entanglement entropy of a free massive Dirac field between two causally disconnected open charts in de Sitter space. We first derive the Bunch-Davies vacuum mode functions of the Dirac field. We find there exists no supercurvature mode for the Dirac field. We then give the Bogoliubov transformation between the Bunch-Davies vacuum and the open chart vacua that makes the reduced density matrix diagonal. We find that the Dirac field becomes more entangled than a scalar field as m 2 /H 2 becomes small, and the difference is maximal in the massless limit.
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ArXiv ePrint: 1612.08954
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Kanno, S., Sasaki, M. & Tanaka, T. Vacuum state of the Dirac field in de Sitter space and entanglement entropy. J. High Energ. Phys. 2017, 68 (2017). https://doi.org/10.1007/JHEP03(2017)068
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DOI: https://doi.org/10.1007/JHEP03(2017)068