Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 37: Matter At Low Temperature: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ... 2

TT 37.5: Talk

Thursday, March 29, 2012, 10:30–10:45, H 3005

Doublon dynamics in the one dimensional extended Hubbard model — •Felix Hofmann and Michael Potthoff — I. Institut für Theoretische Physik, Universität Hamburg, Germany

The existence of repulsively bound states within the Hubbard model has been known since the early work of Hubbard. Here, their time evolution is calculated numerically exact in few-particle subspaces using the Lanczos method and will give insight into their propagation und stability properties. In general, nonvanishing couplings of the extended model, describing dipolar cold gases, cause a renormalization of the hopping parameter. An internal vibrational degree of freedom is accessible in the case of equal couplings and allows for a free propagation of repulsively bound pairs. In an effective description they will be subjected to a nearest-neighbor interaction, which will not give rise to a quantum-droplet phase unlike in the bosonic case [1]. In agreement with Fermi’s golden rule, a power law decay will take place on short time scales until the probability for finding a repulsively bound state in the system approaches a constant value. Already moderate coupling strengths will lead to a high stability which even increases in the presence of more particles in the system, which is also confirmed by calculations for the half-filled system [2]. This establishes the possibilty of the experimental observation of repulsively bound pairs.
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K. A. Al-Hassanieh et al., Phys. Rev. Lett. 100, 166403 (2008).