arXiv subjects

Santanu Mondal

Publications and source records attributed to Santanu Mondal.

95 records · Page 6Linked to original sources

arXiv2012

Exploring autocorrelations in two-flavour Wilson Lattice QCD using DD-HMC algorithm

We perform an extensive study of autocorrelation of several observables in lattice QCD with two degenerate flavours of naive Wilson fermions and unimproved Wilson gauge action using DD-HMC algorithm. We show that (1) at a given lattice spacing, autocorrelation of topological susceptibility decreases with decreasing quark mass and autocorrelations of plaquette and Wilson loop do not increase with decreasing quark mass, (2) autocorrelation of topological susceptibility substantially increases with decreasing lattice spacing but autocorrelation of topological charge density correlator shows only mild increase and (3) increasing the size and the smearing level increase the autocorrelation of Wilson loop.

hep-lat↗

arXiv2011

Topological susceptibility in Lattice QCD with unimproved Wilson fermions

We address a long standing problem regarding topology in lattice simulations of QCD with unimproved Wilson fermions. Earlier attempt with unimproved Wilson fermions at β=5.6 to verify the suppression of topological susceptibility with decreasing quark mass (m_q) was unable to unambiguously confirm the suppression. We carry out systematic calculations for two degenerate flavours at two different lattice spacings (β= 5.6 and 5.8). The effects of quark mass, lattice volume and the lattice spacing on the spanning of different topological sectors are presented. We unambiguously demonstrate the suppression of the topological susceptibility with decreasing quark mass, expected from chiral Ward identity and chiral perturbation theory.

hep-lat↗

arXiv2011

Spanning of Topological sectors, charge and susceptibility with naive Wilson fermions

We study the topological charge and the topological susceptibility in lattice QCD with two degenerate flavors of naive Wilson fermions at two values of lattice spacings and different volumes, for a range of quark masses. Configurations are generated with DDHMC/HMC algorithms and smoothened with HYP smearing. We present integrated autocorrelation time for both topological charge and topological susceptibility at the two lattice spacing values studied. The spanning of different topological sectors as a function of the hopping parameter kappa is presented. The expected chiral behaviour of the topological susceptibility (including finite volume dependence) is observed.

hep-lat↗

arXiv2011

Effect of r averaging on Chiral Anomaly in Lattice QCD with Wilson Fermion: Finite volume and cutoff effects

We demonstrate the effectiveness of averaging over the Wilson parameter r (which has been proposed earlier) in removing the cutoff effects of naive Wilson fermions in both the anomaly term and the pseudoscalar density term in the flavor singlet axial Ward identity at O(g^2) involving slowly varying background gauge fields. We show that it is the physical fermion contribution which is largely influenced by the r averaging. We have studied the possible interplay between finite size and cutoff effects by investigating in detail naive, O(a) improved and OStm Wilson fermion cases for a range of volumes and lattice fermion mass (am). For naive Wilson fermions r averaging is shown to remove the effects of the interplay. We have shown that for the pseudoscalar density term to O (g^2) the lattice result differs from the continuum result by exhibiting considerable am dependence which appears to be a manifestation of cutoff effects with naive Wilson fermion. The pseudoscalar density term to O(g^2) is shown to be almost independent of am when r-averaging is performed.

hep-lat↗

arXiv2010

Chiral Anomaly in Lattice QCD with Twisted Mass Wilson Fermion

The flavour singlet axial Ward identity with Osterwalder-Seiler twisted mass Wilson fermion action is studied on a finite lattice, with finite fermion mass and the Wilson parameter r up to 1. Approach to the infinite volume chiral limit and emergence of the anomaly is significantly better than that obtained with O(a) and O(a^2) improved fermion actions. We have shown explicitly that up to O(g^2), parity violating terms cancel in the Ward identity even at finite volume and finite lattice spacing.

hep-lat↗