## 5. 9. 2013. Seminar: Tao Wang

Thursday 5 September 2013 at 2PM

IPB Library

Seminar organised by Scientific Computing Laboratory

Tao Wang

Department of Physics, Harbin Institute of Technology, China and Department of Physics, Technical University of Kaiserslautern, Germany

**Artificially Tuned Optical Lattices**

Abstract:

In this talk we will focus on two types of artificially tuned optical lattices, namely superlattices and periodically driven optical lattice systems. At first, in view of a superlattice system, we will report on a generalization of the Effective Potential Landau Theory (EPLT) for a single component [1] to multi-component case [2]. In particular, we will suggest how to experimentally realize a Kagome superlattice system where an anisotropic superfluidity should emerge due to two faces of an interaction blockade. Afterwards, we will discuss in detail an optical lattice system, where the s-wave scattering length is modulated periodically [3]. Motivated by the Floquet theory [4], we will show that for large enough driving frequencies the original time-dependent Bose-Hubbard Hamiltonian is well approximated by an effective time-independent Bose-Hubbard model. We can even conclude that the driven many-body system must have the same critical exponents as the much simpler non-driven lattice system provided that the driving amplitude is not too large. Finally, we will present initial results of calculation of the ground-state energy of the Bose-Hubbard model to high orders by invoking the process-chain approach [5]. In the outlook we will discuss the prospects of using the process-chain approach for analyzing artificially tuned optical lattices.

[1] F. E. A. Santos and A. Pelster, Phys. Rev. A 79, 013614 (2009)

[2] T. Wang, X.-F. Zhang, S. Eggert, and A. Pelster, Phys. Rev. A 87, 063615 (2013)

[3] A. Rapp, X. Deng, and L. Santos, Phys. Rev. Lett. 109, 203005 (2012)

[4] E. Arimondo, D. Ciampini, A. Eckardt, M. Holthaus, and O. Morsch, Adv. At. Mol. Opt. Phys. 61, 515 (2012)

[5] N. Teichmann, D. Hinrichs, M. Holthaus, and A. Eckardt, Phys. Rev. B 79, 224515 (2009)