Abstract
Author(s): Rangamani, M; Rozali, M; Van Raamsdonk, M | Abstract: Abstract: We study the dynamics of a strongly-coupled quantum field theory in a cosmological spacetime using the holographic AdS/CFT correspondence. Specifically we consider a confining gauge theory in an expanding FRW universe and track the evolution of the stress-energy tensor during a period of expansion, varying the initial temperature as well as the rate and amplitude of the expansion. At strong coupling, particle production is inseparable from entropy production. Consequently, we find significant qualitative differences from the weak coupling results: at strong coupling the system rapidly loses memory of its initial state as the amplitude is increased. Furthermore, in the regime where the Hubble parameter is much smaller than the initial temperature, the dynamics is well-modelled as a plasma evolving hydrodynamically.
Highlights
We study the dynamics of a strongly-coupled quantum field theory in a cosmological spacetime using the holographic AdS/conformal field theories (CFTs) correspondence
In the regime where the Hubble parameter is much smaller than the initial temperature, the dynamics is well-modelled as a plasma evolving hydrodynamically
At strong coupling particle production is expected to be accompanied by rapid local thermalization, a feature that is postponed at weak coupling to the end of the expansion
Summary
In the deconfined phase at large ceff, local 4+1 dimensional quantities do not depend on the scale c, a property known as “large N volume independence” [4] This follows from the fact that the finite c solutions are obtained from the c = ∞ solutions by a trivial identification xc ∼ xc + c. Using this and scale invariance we we can parameterize the final 3+1 dimensional energy density in terms of the dimensionless quantities a and v = v/T as (a, v, T0) = C c v5 f (a, v) ,. Our goal in the remaining sections will be to compute the functions F (a, v) and GT (a, v) for a holographic theory and for a weakly coupled field theory and compare the results.
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