Novel physics of polar molecules in optical lattices

• Applicant: Professor Dr. Luis Santos
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2010 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 160524815

• Final Report Year: 2014

Final Report Abstract

The long-range anisotropic character of the dipole-dipole interaction leads to rich new physics in dipolar gases, already partially unveiled by recent experiments on atomic magnetic dipoles. Recent experiments on heteronuclear molecules allow to foreseeing in the next future a quantum degenerate gas of polar molecules, in which electric dipole-dipole interactions may completely dominate the system. This may be particularly striking for polar molecules in optical lattices, which may present siginificant dipole-induced inter-site interactions, in stark contrast to non-dipolar gases, where inter-site interactions are vanishingly small. This project has focused on the novel effects introduced by the dipole-dipole interaction in ultra-cold dipolar gases in optical lattices, with a particular emphasis on three different scenarios, where new physics arises from inter-site interactions. On one hand, and in close collaboration with experiments, we have studied the stability, collapse dynamics, and excitations of dipolar condensates in 1D lattices, showing that inter-site interactions significantly affect the condensate stability even in absence of intersite hopping. On other hand, we have studied the possibility of forming interlayer composites of polar molecules, i.e. non-local composites formed by molecules which are physically at two different and non-overlapping layers. On yet another hand, we have studied how inter-site interactions modify the physics of polar bosons in disordered lattices, and reported, in close collaboration with experimentalists, the first observation of non-equlibrium quantum dynamics in dipolar lattice gases.

Publications

• Interlayer superfluidity in bilayer systems of fermionic polar molecules, Phys. Rev. Lett. 105, 215302 (2010)
  A. Pikovski, M. Klawunn, G.V. Shlyapnikov, and L. Santos
  
• Dipolar stabilization of an attractive Bose gas in a one-dimensional lattice, Phys. Rev. A 84, 053601 (2011)
  S. Müller, J. Billy, E. A. L. Henn, H. Kadau, A. Griesmaier, M. Jona-Lasinio, L. Santos, and T. Pfau
  
• Non-local state-swapping of polar molecules in bilayers, Phys. Rev. A 84, 061605(R)(2011)
  A. Pikovski, M. Klawunn, A. Recati, and L. Santos
  
• Confinement-induced collapse of a dipolar Bose-Einstein condensate, Phys. Rev. A 86, 051603 (2012)
  J. Billy, E. A. L. Henn, S. Müller, T. Maier, H. Kadau, A. Griesmaier, M. Jona-Lasinio, L. Santos and T. Pfau
  
• Spontaneous crystallization and filamentation of solitons in dipolar condensates, Phys. Rev. A 85, 033618 (2012)
  K. Lakomy, R. Nath and L. Santos
  
• Non-equilibrium quantum magnetism in a dipolar lattice gas, Phys. Rev. Lett. 111, 185305 (2013)
  A. de Paz, A. Sharma, A. Chotia, E. Marechal, J. Huckans, P. Pedri, L. Santos, O. Gorceix, L. Vernac, and B. Laburthe-Tolra
  
• Polar bosons in one-dimensional disordered optical lattices, Phys. Rev. B 87, 195101 (2013)
  X. Deng, R. Citro, E. Orignac, A. Minguzzi, and L. Santos
  
• Roton confinement in dipolar Bose-Einstein condensates, Phys. Rev. A 88, 049905 (2013)
  M. Jona-Lasinio, K. Lakomy, and L. Santos
  
• Self-bound many-body states of quasi-one-dimensional dipolar Fermi gases: exploiting Bose-Fermi mappings for generalized contact interactions, Phys. Rev. A 88, 033611 (2013)
  F. Deuretzbacher, G. M. Bruun, C. J. Pethick, M. Jona-Lasinio, S. M. Reimann and L. Santos
  
• Time-of-Flight Roton Spectroscopy in Dipolar Bose-Einstein Condensates, Phys. Rev. A 88, 025603 (2013)
  M. Jona-Lasinio, K. Lakomy, and L. Santos