Abstract
For an -symmetric scalar field theory with Euclidean action , where is a vector of real-field components, variational perturbation theory through seven loops is employed for to compute the renormalized value of at the phase transition. Its exact large- limit is determined as well. We also extend an earlier computation of the interaction-induced shift from to . For , the results for the two quantities are used to compute the second-order shift of the condensation temperature of a dilute Bose gas, both in the homogenous case and for the wide limit of a harmonic trap. Our results are in agreement with earlier Monte Carlo simulations for . The Appendix contains previously unpublished numerical seven-loop data.
- Received 7 June 2004
DOI:https://doi.org/10.1103/PhysRevA.70.043621
©2004 American Physical Society