Dublin Quantum Field Theory Seminar

                            Synge Lecture Theatre
                    School of Mathematics, Hamilton Building
                             Trinity College Dublin

                                 Time: 4.15 pm


June 3 Francesco Di Renzo (Dipartimento di Fisica & INFN, Università di Parma)

Unquenched Numerical Stochastic Perturbation Theory

In recent years a Numerical implementation of Stochastic Perturbation
Theory (NSPT) has been realized, which has lead to unprecedented high
orders in pertubative expansions in Lattice Gauge Theory (LGT). After a
brief introduction to the foundations of the method, we proceed to
discuss computations in full (unquenched) lattice QCD. The inclusion of
fermionic loops contribution in NSPT has a very nice feature: it does not
cost so much (provided only that an FFT can be implemented in a fairly
efficient way). This is to be contrasted with the heavy computational
effort requested for non perturbative unquenched lattice QCD. This
suggests the strategy of going back to perturbation theory for the
(unquenched) computation of quantities like improvement coefficients and
renormalisation constants. Multi-loop computations are a reasonable goal.
Performance of the current implementation of unquenched NSPT for Lattice
SU(3) is reviewed and the status of first computations undertaken is
reported.



Back to seminar list.

Last changed 22 April 2002.