Properties of quark gluon plasma at weak and strong coupling

In this thesis properties of probe particle traveling through quark gluon plasma as created in heavy ion collisions are investigated. In the first part, probability distribution P(k1 ) is calculated for an energetic parton that propagates for a distance L through a weakly coupled medium without radiating to pick up transverse momentum k1. Results for P(k1 ) in weakly coupled quark gluon plasma are compared to expectations from holographic calculations that assume a plasma that is strongly coupled at all length scales. It is found that the shape of P(k1) at modest k1 may not be very different in weakly coupled and strongly coupled plasmas, but P(k1 ) must be parametrically larger in a weakly coupled plasma than in a strongly coupled plasma - at large enough k1. In the second part of the thesis the drag force acting on a heavy quark propagating through the matter which is far from or close to equilibrium in a strongly coupled gauge theory that can be analyzed holographically is computed and studied. It is found that fluid velocity and temperature gradients affect the drag force but does not substantially modify it as long as fluid is close to equilibrium. When quark is away from equilibrium, the modification of drag force manifests in terms of the delay time with respect to equilibrium expectations. These aspects are illustrated for the example of two colliding shockwaves where fluid is far from equilibrium at early times as well as for any fluid close to equilibrium in which case drag force expressions are obtained analytically.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2014

Author dc:creator

• Lekaveckas, Mindaugas

Advisor dc:contributor.advisor

• Krishna Rajagopal and Hong Liu.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/91391

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/91391