Nonperturbative renormalization group and momentum dependence of n-point functions. I

Journal Article · Wed Nov 15 04:00:00 EST 2006 · Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics

DOI:https://doi.org/10.1103/PHYSREVE.74.051116· OSTI ID:21072338

Blaizot, Jean-Paul; Mendez-Galain, Ramon; Wschebor, Nicolas ^[1]

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1. ECT, Villa Tambosi, strada delle Tabarelle 286, 38050 Villazzano (Italy)

We present an approximation scheme to solve the nonperturbative renormalization group equations and obtain the full momentum dependence of the n-point functions. It is based on an iterative procedure where, in a first step, an initial ansatz for the n-point functions is constructed by solving approximate flow equations derived from well motivated approximations. These approximations exploit the derivative expansion and the decoupling of high momentum modes. The method is applied to the O(N) model. In leading order, the self-energy is already accurate both in the perturbative and the scaling regimes. A stringent test is provided by the calculation of the shift {delta}T{sub c} in the transition temperature of the weakly repulsive Bose gas, a quantity which is particularly sensitive to all momentum scales. The leading order result is in agreement with lattice calculations, albeit with a theoretical uncertainty of about 25%.

• OSTI ID: 21072338
• Journal Information: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics Journal Issue: 5 Vol. 74; ISSN PLEEE8; ISSN 1063-651X
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
APPROXIMATIONS
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
BOSONS
DECOUPLING
EQUATIONS
ITERATIVE METHODS
RENORMALIZATION
SELF-ENERGY
TRANSITION TEMPERATURE