What is the entropy in entropic gravity?
Abstract
We explore theories in which gravity arises as a consequence of entropy. We distinguish between two approaches to this idea: holographic gravity, in which Einstein’s equation arises from keeping entropy stationary in equilibrium under variations of the geometry and quantum state of a small region, and thermodynamic gravity, in which Einstein’s equation emerges as a local equation of state from constraints on the area of a dynamical light sheet in a fixed spacetime background. Examining holographic gravity, we argue that its underlying assumptions can be justified in part using recent results on the form of the modular energy in quantum field theory. For thermodynamic gravity, on the other hand, we find that it is difficult to formulate a selfconsistent definition of the entropy, which represents an obstacle for this approach. Our investigation points the way forward in understanding the connections between gravity and entanglement.
 Authors:

 California Institute of Technology (CalTech), Pasadena, CA (United States)
 Publication Date:
 Research Org.:
 California Institute of Technology (CalTech), Pasadena, CA (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), High Energy Physics (HEP) (SC25); Gordon and Betty Moore Foundation
 OSTI Identifier:
 1600671
 Alternate Identifier(s):
 OSTI ID: 1258721
 Grant/Contract Number:
 SC0011632; DGE1144469
 Resource Type:
 Accepted Manuscript
 Journal Name:
 Physical Review D
 Additional Journal Information:
 Journal Volume: 93; Journal Issue: 12; Journal ID: ISSN 24700010
 Publisher:
 American Physical Society (APS)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 79 ASTRONOMY AND ASTROPHYSICS
Citation Formats
Carroll, Sean M., and Remmen, Grant N. What is the entropy in entropic gravity?. United States: N. p., 2016.
Web. doi:10.1103/PhysRevD.93.124052.
Carroll, Sean M., & Remmen, Grant N. What is the entropy in entropic gravity?. United States. doi:10.1103/PhysRevD.93.124052.
Carroll, Sean M., and Remmen, Grant N. Tue .
"What is the entropy in entropic gravity?". United States. doi:10.1103/PhysRevD.93.124052. https://www.osti.gov/servlets/purl/1600671.
@article{osti_1600671,
title = {What is the entropy in entropic gravity?},
author = {Carroll, Sean M. and Remmen, Grant N.},
abstractNote = {We explore theories in which gravity arises as a consequence of entropy. We distinguish between two approaches to this idea: holographic gravity, in which Einstein’s equation arises from keeping entropy stationary in equilibrium under variations of the geometry and quantum state of a small region, and thermodynamic gravity, in which Einstein’s equation emerges as a local equation of state from constraints on the area of a dynamical light sheet in a fixed spacetime background. Examining holographic gravity, we argue that its underlying assumptions can be justified in part using recent results on the form of the modular energy in quantum field theory. For thermodynamic gravity, on the other hand, we find that it is difficult to formulate a selfconsistent definition of the entropy, which represents an obstacle for this approach. Our investigation points the way forward in understanding the connections between gravity and entanglement.},
doi = {10.1103/PhysRevD.93.124052},
journal = {Physical Review D},
number = 12,
volume = 93,
place = {United States},
year = {2016},
month = {6}
}
Web of Science
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