Project Details
Projekt
FOR 723: Functional Renormalisation Group for Correlated Fermion Systems
Subject Area
Physics
Term
from 2007 to 2017
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 21278441
In recent years, the functional renormalisation group (RG) has led to significant progress in the understanding of correlated fermion systems. This theoretical method is based on a successive integration of degrees of freedom associated to energy scales, from high to low energies. Because the fundamental equations of the functional RG are exact, the quality of approximation schemes (which are necessary in all interesting applications) can be tested and improved systematically. Some of the important successes of the method are the unbiased analysis of instabilities of the Fermi liquid state in two dimensions, which also allows to obtain phase diagrams, as well as a precise analysis of the behaviour of quantum wires.
In this Research Unit we apply and extend the method to situations of the highest physical interest. Among the projects are the investigation of the broken-symmetry phases of models of high-temperature superconductors, in particular the analysis of the interplay and competition between different ordering tendencies, closely connected questions about quantum phase transitions in metallic systems and the behaviour of ultracold atom gases, as well as transport through quantum dots and quantum wires and, more generally, nonequilibrium phenomena in Kondo and Anderson models. In many of these projects, a central role, both physically and technically, is played by the dynamics of the fields that describe collective excitations and order parameters at very low energy scales.
By joining efforts and combining our expertise and experience we will work to establish the method firmly as a means for doing accurate calculations, to gain a good understanding of the infrared behaviour in these situations, and, in certain cases, to compare to experiments. Moreover, the cooperation within the Research Unit will also further the understanding of the properties of the RG itself, which will be useful for many other fields of fundamental physics, in particular nuclear and high-energy physics.
In this Research Unit we apply and extend the method to situations of the highest physical interest. Among the projects are the investigation of the broken-symmetry phases of models of high-temperature superconductors, in particular the analysis of the interplay and competition between different ordering tendencies, closely connected questions about quantum phase transitions in metallic systems and the behaviour of ultracold atom gases, as well as transport through quantum dots and quantum wires and, more generally, nonequilibrium phenomena in Kondo and Anderson models. In many of these projects, a central role, both physically and technically, is played by the dynamics of the fields that describe collective excitations and order parameters at very low energy scales.
By joining efforts and combining our expertise and experience we will work to establish the method firmly as a means for doing accurate calculations, to gain a good understanding of the infrared behaviour in these situations, and, in certain cases, to compare to experiments. Moreover, the cooperation within the Research Unit will also further the understanding of the properties of the RG itself, which will be useful for many other fields of fundamental physics, in particular nuclear and high-energy physics.
DFG Programme
Research Units
Projects
- Central project (Applicant Salmhofer, Manfred )
- Competing order parameters and flows into phases with broken symmetries (Applicants Honerkamp, Carsten ; Salmhofer, Manfred )
- Correlation effects in quantum dots and wires (Applicant Meden, Volker )
- Functional renormalization group for ultracold atoms (Applicants Gies, Holger ; Kopietz, Peter ; Wetterich, Christof )
- Functional RG in nonequilibrium (Applicants Andergassen, Sabine ; Schoeller, Herbert )
- Quantum criticality: coupled renormalization of electrons and order parameter fluctuations (Applicant Metzner, Walter )
Spokesperson
Professor Dr. Manfred Salmhofer
