Collective modes of an anisotropic quark-gluon plasma: II

By Paul Romatschke, Michael Strickland. 2003

176 citations recorded by the source corpus.

We continue our exploration of the collective modes of an anisotropic quark-gluon plasma by extending our previous analysis to arbitrary Riemann sheets. We demonstrate that in the presence of momentum-space anisotropies in the parton distribution functions there are new relevant singularities on the neighboring unphysical sheets. We then show that for sufficiently strong anisotropies that these singularities move into the region of spacelike momentum and their effect can extend down to the physical sheet. In order to demonstrate this explicitly we consider the polarization tensor for gluons propagating parallel to the anisotropy direction. We derive analytic expressions for the gluon structure functions in this case and then analytically continue them to unphysical Riemann sheets. Using the resulting analytic continuations we numerically determine the position of the unphysical singularities. We then show that in the limit of infinite contraction of the distribution function along the anisotropy direction that the unphysical singularities move onto the physical sheet and result in real spacelike modes at large momenta for all 'out-of-plane' angles of propagation.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/06376253b3411658fefe539adb793e65312b0328

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Citations in the corpus

Dissipative Dynamics of Highly Anisotropic Systems (2010, methodology): “We will introduce an ansatz for faniso which approximates the system via ellipsoidal equal occupation number surfaces as opposed to the spherical ones associated with the isotropic equilibrium distribution function [12].”
Collective Phenomena in the Non-Equilibrium Quark-Gluon Plasma (2008, methodology): “This particular class of distribution functions has been first discussed by Romatschke and Strickland in [63] and [142].”
Three-loop HTLpt thermodynamics at finite temperature and chemical potential (2014, methodology): “Quantities such as the dilepton production rate [96, 97], photon production rate [98], single quark and quark anti-quark potentials [99–107], fermion damping rate [108–110], photon damping rate [111], gluon damping rate [112, 113], jet energy loss [114–125], plasma instabilities [126–132], thermal a”
Relativistic Fluid Dynamics in and out of Equilibrium (2017, background): “Such anisotropic deformations have been considered in the context of plasma instabilities in systems with momentum anisotropies [184] and are the basis for so-called anisotropic hydrodynamics.”