Title:	A note on entanglement entropy, coherent states and gravity
Authors:	Varadarajan, Madhavan
Issue Date:	Mar-2016
Publisher:	Springer
Citation:	General Relativity and Gravitation, 2016, Vol.48, p35
Abstract:	The entanglement entropy of a free quantum field in a coherent state is independent of its stress energy content. We use this result to highlight the fact that while the Einstein equations for first order variations about a locally maximally symmetric vacuum state of geometry and quantum fields seem to follow from Jacobson’s principle of maximal vacuum entanglement entropy, their possible derivation from this principle for the physically relevant case of finite but small variations remains an open issue. We also apply this result to the context of Bianchi’s identification, independent of unknown Planck scale physics, of the first order variation of Bekenstein–Hawking area with that of vacuum entanglement entropy. We argue that under certain technical assumptions this identification seems not to be extendible to the context of finite but small variations to coherent states. Our particular method of estimation of entanglement entropy variation reveals the existence of certain contributions over and above those of References Jacobson (arXiv:1505.04753, 2015), Bianchi (arXiv:1211.0522 [gr-qc], 2012). We discuss the sense in which these contributions may be subleading to those in References Jacobson (arXiv:1505.04753, 2015), Bianchi (arXiv:1211.0522 [gr-qc], 2012).
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/6440
ISSN:	0001-7701 1572-9532 (Online)
Alternative Location:	http://arxiv.org/abs/1602.00106 http://dx.doi.org/10.1007/s10714-016-2030-9 http://adsabs.harvard.edu/abs/2016GReGr..48...35V
Copyright:	2016 Springer
Appears in Collections:	Research Papers (TP)

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