[Triumf-seminars] TRIUMF Theory Seminar today at 13:00

[postmaster at admin.triumf.ca]

Date/Time: Thu 2011-01-20 at 13:00

Location:  Theory Room         

Speaker:   Heiko Hergert (MSU and NSCL)

Title:     Similarity Renormalization Group Techniques for the Nuclear Many-Body Problem

Abstract: The Similarity Renormalization Group (SRG) is a powerful and versatile tool for many-body physics. Its primary application in the framework of the nuclear many-body problem is the derivation of effective interactions from underlying realistic NN (and recently 3N) interactions. SRG-evolved interactions have greatly improved convergence properties in nuclear many-body calculations, extending the range of Ab Initio methods to heavier nuclei, and enabling mean-field based approaches while maintaining a stringent link to the underlying vacuum interactions. I will present select results for ground and excited states, and discuss open issues.

A recent development is the In-Medium SRG, where the evolution is carried out directly in the A-body system (i.e., at finite density). By constructing a generator from the normal-ordered Hamiltonian, the ground state is decoupled from particle-hole excitations. In this sense, the IM-SRG constitutes an Ab Initio technique for solving the many-body problem. There is evidence that the 
evolved Hamiltonian can be reliably truncated at the two-body level, including dominant contributions from three- or higher many-body forces through a density dependence. This would allow a quasi-exact treatment of the many-body problem with established two-body techniques.




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