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Kazem Bitaghsir Fadafan

Publications and source records attributed to Kazem Bitaghsir Fadafan.

38 records · Page 3Linked to original sources
arXiv2009

$R^2$ curvature-squared corrections on drag force

The effect of finite-coupling corrections to the drag force on a moving heavy quark in the Super Yang-Mills plasma is investigated. These corrections are related to curvature-squared corrections in the corresponding gravity dual. The results are compared with the dual gauge theory. It is shown that curvature-squared corrections affect the drag force. It is shown that corrections to the drag force depend on the velocity of the heavy quark. The diffusion coefficient of non-relativistic heavy quarks is calculated from the drag force. In addition, we also calculate the drag force on a moving heavy quark in the Gauss-Bonnet background.

hep-th↗
arXiv2008

Stirring Strongly Coupled Plasma

We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implications of our results for a quark that is moving through the plasma in a straight line while decelerating, although in this case the classical calculation breaks down at the same value of the deceleration at which the radiation-dominated regime sets in.

hep-ph↗