Nonperturbative flow equations from running expectation values
Date
2003-08
Authors
Scholtz, F. G.
Bartlett, Bruce H.
Geyer, H. B.
Journal Title
Journal ISSN
Volume Title
Publisher
American Physical Society (APS)
Abstract
We show that Wegner’s flow equations, as recently discussed in the Lipkin model, can be solved selfconsistently.
This leads to a nonlinear differential equation which fully determines the order parameter
as a function of the dimensionless coupling constant, even across the phase transition. Since we consider
an expansion in the fluctuations, rather than the conventional expansion in the coupling constant,
convergence to the exact results is found in both phases when taking the thermodynamic limit.
Description
The original publication is available at http://prl.aps.org/abstract/PRL/v91/i8/e080602
Keywords
Nonperturbative techniques, Nonlinear differential equation, Flow equations, Interacting quantum systems
Citation
Scholtz, F. G., Bartlett, B. H. & Geyer, H. B. 2003. Nonperturbative flow equations from running expectation values. Physical Review Letters , 91(8), doi:10.1103/PhysRevLett.91.080602.