TY - JOUR
T1 - Bound on the speed of sound from holography
AU - Cherman, Aleksey
AU - Cohen, Thomas D.
AU - Nellore, Abhinav
PY - 2009/9/3
Y1 - 2009/9/3
N2 - We show that the squared speed of sound vs2 is bounded from above at high temperatures by the conformal value of 1/3 in a class of strongly coupled four-dimensional field theories, given some mild technical assumptions. This class consists of field theories that have gravity duals sourced by a single-scalar field. There are no known examples to date of field theories with gravity duals for which vs2 exceeds 1/3 in energetically favored configurations. We conjecture that vs2=1/3 represents an upper bound for a broad class of four-dimensional theories.
AB - We show that the squared speed of sound vs2 is bounded from above at high temperatures by the conformal value of 1/3 in a class of strongly coupled four-dimensional field theories, given some mild technical assumptions. This class consists of field theories that have gravity duals sourced by a single-scalar field. There are no known examples to date of field theories with gravity duals for which vs2 exceeds 1/3 in energetically favored configurations. We conjecture that vs2=1/3 represents an upper bound for a broad class of four-dimensional theories.
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U2 - 10.1103/PhysRevD.80.066003
DO - 10.1103/PhysRevD.80.066003
M3 - Article
AN - SCOPUS:70349868239
SN - 1550-7998
VL - 80
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
IS - 6
M1 - 066003
ER -