Topological px+ipy superfluid phase of fermionic polar molecules

• Published in: Physical Review A
• Main Authors: Levinsen, J., Cooper, N.R., Shlyapnikov, G.V.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: IPY
• Online Access: https://dare.uva.nl/personal/pure/en/publications/topological-pxipy-superfluid-phase-of-fermionic-polar-molecules(65fdcdc3-4158-423d-8f34-722f65211cbd).html; https://doi.org/10.1103/PhysRevA.84.013603

We discuss the topological px+ipy superfluid phase in a 2D gas of single-component fermionic polar molecules dressed by a circularly polarized microwave field. This phase emerges because the molecules may interact with each other via a potential Vo(r) that has an attractive dipole-dipole 1/r^3 tail, which provides p-wave superfluid pairing at fairly high temperatures. We calculate the amplitude of elastic p-wave scattering in the potential Vo(r) taking into account both the anomalous scattering due to the dipole-dipole tail and the short-range contribution. This amplitude is then used for the analytical and numerical solution of the renormalized BCS gap equation which includes the second order Gor'kov-Melik-Barkhudarov corrections and the correction related to the effective mass of the quasiparticles. We find that the critical temperature Tc can be varied within a few orders of magnitude by modifying the short-range part of the potential Vo(r). The decay of the system via collisional relaxation of molecules to dressed states with lower energies is rather slow due to the necessity of a large momentum transfer. The presence of a constant transverse electric field reduces the inelastic rate, and the lifetime of the system can be of the order of seconds even at 2D densities ~10^9 cm^-2}. This leads to Tc of up to a few tens of nanokelvins and makes it realistic to obtain the topological px+ipy phase in experiments with ultracold polar molecules.