RGApproachToInteractingFermions: Difference between revisions

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The basic proceedure is as follows.  Let us consider a given interacting Hamiltonian, and write the associated partition function in path integral form:
The basic proceedure is as follows.  Let us consider a given interacting Hamiltonian, and write the associated partition function in path integral form:


<math>Z=\int{D[\psi^{\ast},\psi] e^{-S[\psi^{\ast},\psi]},</math>
<math> \displaystyle Z=\int{D[\psi^{\ast},\psi] e^{-S[\psi^{\ast},\psi]}},</math>


where the action <math>S</math> is
where the action <math>S</math> is

Revision as of 14:49, 30 November 2010

Introduction

The renormalization group (RG) is a very powerful tool in physics. Essentially, it is a way to continuously map a given theory onto other theories possessing the same low-energy physics by successively integrating out "fast", or high-energy, modes. This is expressed in terms of differential equations giving the "flows" of different coupling constants that appear in the theory.

The basic proceedure is as follows. Let us consider a given interacting Hamiltonian, and write the associated partition function in path integral form:

where the action is

System at half-filling in one dimension

System with spherically symmetric Fermi surface in two or three dimensions

System with non-spherically symmetric Fermi surface in two dimensions

System with nested Fermi surface in two dimensions