Hannover 2013 – scientific programme

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A: Fachverband Atomphysik

A 29: Poster: Ultra-cold atoms, ions and BEC (with Q)

A 29.4: Poster

Wednesday, March 20, 2013, 16:00–18:30, Empore Lichthof

Compressional and surface modes of the trapped dipolar gases — •Alexey Filinov^1,2 and Michael Bonitz¹ — ¹Institut für Theoretische Physik und Astrophysik, D-24098 Kiel, Germany — ²Joint Institute for High Temperatures RAS, 125412 Moscow, Russia

The low-lying collective excitations -monopole and multipole modes- are analyzed based on the excitation-energy sum rules [1]. This formalism allows to estimate an upper bound for the excitation energies. The involved frequency moments of the strength function are estimated as a trace over the corresponding commutators between an excitation operator and the many-body Hamiltonian in thermodynamic equilibrium. Temperature and dipole interaction strength dependencies of the breathing and quadrupole modes of a 3D trapped dipolar gas are presented. One of our goals is to analyze the frequency shifts of the modes similar to that observed in the experiments with a ⁸⁷Rb gas at temperatures near T_c [2]. Our analysis is based on finite-temperature quantum MC simulations [3].

[1] E. Lipparini and S. Stringari, Phys. Rep. 175, 103 (1989); S. Stringari, Phys. Rev. Lett. 77, 2360 (1996). [2] D.S. Jin and et al., ibid 78, 764 (1997); D.M. Stamper-Kurn and et al., ibid 81, 500 (1998). [3] A. Filinov and et al., ibid 105, 070401 (2010).