Papers by Debasish Banerjee
Journal of High Energy Physics, 2016
We describe and test a nonperturbatively improved single-plaquette lattice action for 4-d SU(2) a... more We describe and test a nonperturbatively improved single-plaquette lattice action for 4-d SU(2) and SU(3) pure gauge theory, which suppresses large fluctuations of the plaquette, without requiring the naive continuum limit for smooth fields. We tune the action parameters based on torelon masses in moderate cubic physical volumes, and investigate the size of cutoff effects in other physical quantities, including torelon masses in asymmetric spatial volumes, the static quark potential, and gradient flow observables. In 2-d O(N) models similarly constructed nearest-neighbor actions have led to a drastic reduction of cutoff effects, down to the permille level, in a wide variety of physical quantities. In the gauge theories, we find significant reduction of lattice artifacts, and for some observables, the coarsest lattice result is very close to the continuum value. We estimate an improvement factor of 40 compared to using the Wilson gauge action to achieve the same statistical accuracy and suppression of cutoff effects. The simplicity of the gauge action makes it amenable for dynamical fermion simulations.
Physical Review D, 2012
The momentum diffusion coefficient for heavy quarks is studied in a deconfined gluon plasma in th... more The momentum diffusion coefficient for heavy quarks is studied in a deconfined gluon plasma in the static approximation by investigating a correlation function of the color electric field using Monte Carlo techniques. The diffusion coefficient is extracted from the long distance behavior of such a correlator. For temperatures Tc < T < ∼ 2Tc, our nonperturbative estimate of the diffusion coefficient is found to be very different from the leading order perturbation theory, and is in the right ballpark to explain the heavy quark flow seen by PHENIX at RHIC.
Physical Review Letters, 2012
Physical Review D, 2008
The thermodynamics of massless ideal gas of overlap quarks has been investigated both analyticall... more The thermodynamics of massless ideal gas of overlap quarks has been investigated both analytically and numerically for both zero and nonzero baryon chemical potential. Any µ 2-divergence is shown analytically to be absent for a class of actions with nonzero chemical potential. All such actions are shown to violate chiral invariance. While the parameter M can be shown to be irrelevant in the continuum limit, as expected, it is shown numerically that the continuum limit can be reached with relatively coarser lattices for 1.5 ≤ M ≤ 1.6. Numerical limitations of the existing method of introduction of chemical potential are demonstrated. Finally we also show that the energy density for the massive overlap fermions has the correct continuum limit.
Lecture Notes in Physics, 2009
These introductory lectures present a broad overview of the physics of high parton densities in Q... more These introductory lectures present a broad overview of the physics of high parton densities in QCD and its application to our understanding of the early time dynamics in heavy ion collisions.
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Papers by Debasish Banerjee