Activities
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Seminars
| Seminar on Theoretical and Computational Physics:
| | Title | Dynamical mean field theory for the Dynamic Hubbard model
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| Speaker | Dr. Bạch Hương Giang
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| Affiliation | Center for Theoretical Physics, Institute of Physics
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| Date | Tuesday, 25-10-2011
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| Time | 10:00AM
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| Location | Meeting room on the 1st floor, Institute of Physics, 10 Dao Tan, Ba Dinh, Hanoi
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| Abstract | Dynamical mean field theory is applied to the Dynamic Hubbard model. The Dynamic Hubbard model describes the orbital relaxation that occurs when two electrons occupy the same site, by using a pseudospin field at each site. Near half-filling the Mott physics associated with the static Hubbard model is enhanced by the coupling to this auxiliary field. More importantly, the Dynamic Hubbard model is strongly electron-hole asymmetric, as can be readily seen for a number of properties. We compute the quasiparticle spectral weight and the frequency dependent spectral function to illustrate some generic features of this model. In particular, holes tend to be heavier than electrons. In the antiadiabatic limit, the linear dependence of the quasiparticle weight on filling shows good agreement with a previously known analytical result in the correlated hopping model.
The optical conductivity is also calculated analytically in a dimer with various numbers of particles. Further understanding of the optical conductivity is achieved by the two-site dynamical mean field theory in the thermodynamic limit. The dependence of optical conductivity on the number of particles reveals the effect of the pseudospin on the spectral weight distribution as a function of frequency.
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