TY - JOUR

T1 - Einstein equations for generalized theories of gravity and the thermodynamic relation δq=tδs are equivalent

AU - Brustein, Ram

AU - Hadad, Merav

N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.

PY - 2009/9/1

Y1 - 2009/9/1

N2 - We show that the equations of motion of generalized theories of gravity are equivalent to the thermodynamic relation δQ=TδS. Our proof relies on extending previous arguments by using a more general definition of the Noether charge entropy. We have thus completed the implementation of Jacobson's proposal to express Einstein's equations as a thermodynamic equation of state. Additionally, we find that the Noether charge entropy obeys the second law of thermodynamics if the energy-momentum tensor obeys the null energy condition. Our results support the idea that gravitation on a macroscopic scale is a manifestation of the thermodynamics of the vacuum.

AB - We show that the equations of motion of generalized theories of gravity are equivalent to the thermodynamic relation δQ=TδS. Our proof relies on extending previous arguments by using a more general definition of the Noether charge entropy. We have thus completed the implementation of Jacobson's proposal to express Einstein's equations as a thermodynamic equation of state. Additionally, we find that the Noether charge entropy obeys the second law of thermodynamics if the energy-momentum tensor obeys the null energy condition. Our results support the idea that gravitation on a macroscopic scale is a manifestation of the thermodynamics of the vacuum.

UR - http://www.scopus.com/inward/record.url?scp=69549112647&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.103.101301

DO - 10.1103/PhysRevLett.103.101301

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AN - SCOPUS:69549112647

SN - 0031-9007

VL - 103

JO - Physical Review Letters

JF - Physical Review Letters

IS - 10

M1 - 101301

ER -