Efficient Evaluation of Effective Action in Radial Backgrounds
Abstract
Recently a new caculational scheme for effective actions in radial background fields was developed. The effective action is expressed as an infinite sum of partialwave contributions, using the rotational symmetry of the system. The sum becomes convergent after proper regularization and renormalization, but the rate of convergence is rather slow. We introduce a systematic way of accelerating the rate of convergence. This method is based on a radial WKB series in the angular momentum cutoff. We demonstrate the power of this scheme by applying it to the calculation of instanton determinant in QCD.
 Publication:

Quantum Field Theory Under the Influence of External Conditions (QFEXT09)
 Pub Date:
 April 2010
 DOI:
 10.1142/9789814289931_0053
 arXiv:
 arXiv:0912.0084
 Bibcode:
 2010qfti.conf..426M
 Keywords:

 Effective action;
 partial wave;
 functional determinant;
 WKB;
 renormalization;
 High Energy Physics  Theory
 EPrint:
 5 pages, 1 figuers. Talk given at the Ninth Conference on Quantum Field Theory under the Influence of External Conditions, 2125 September 2009, Oklahoma, USA