Finite volume QCD at fixed topological charge
Abstract
In finite volume the partition function of QCD with a given θ is a sum of different topological sectors with a weight primarily determined by the topological susceptibility. If a physical observable is evaluated only in a fixed topological sector, the result deviates from the true expectation value by an amount proportional to the inverse spacetime volume 1/V. Using the saddle point expansion, we derive formulas to express the correction due to the fixed topological charge in terms of a 1/V expansion. Applying this formula, we propose a class of methods to determine the topological susceptibility in QCD from various correlation functions calculated in a fixed topological sector.
 Publication:

Physical Review D
 Pub Date:
 September 2007
 DOI:
 10.1103/PhysRevD.76.054508
 arXiv:
 arXiv:0707.0396
 Bibcode:
 2007PhRvD..76e4508A
 Keywords:

 12.38.Gc;
 11.15.Ha;
 Lattice QCD calculations;
 Lattice gauge theory;
 High Energy Physics  Lattice;
 High Energy Physics  Theory
 EPrint:
 22pages, references added