Creating Superconducting Condensates

Igor Sapina, Thomas Dahm

We study center-of-mass oscillations of a dipolar Bose–Einstein condensate in the vicinity of a superconducting surface. We show that the magnetic field of the magnetic dipoles induces eddy currents in the superconductor, which act back on the Bose–Einstein condensate. This leads to a shift of its oscillation frequency and to an anharmonic coupling of the Bose–Einstein condensate with the superconductor. The anharmonicity creates a coupling to one of the collective modes of the condensate that can be resonantly enhanced if the parameters of the condensate are chosen properly. This provides a new physical mechanism to couple a Bose–Einstein condensate and a superconductor, which becomes significant for 52 Cr, 168 Er or 164 Dy condensates in superconducting microtraps.

M.Á. De la Casa, J. Getino, MANUEL DE LLANO +1 more

Deborah Jin

The quantum mechanical phenomenon of Bose-Einstein condensation appears throughout physics with manifestations ranging from superconductivity in metals to superfluidity in nuclei and neutron stars. In most cases the condensation emerges due to correlations or pairing of fermionic particles. We explore this quantum behavior in a uniquely controllable and clean system consisting of an ultracold gas of atoms. In particular, by tuning the interactions between the fermionic atoms that make up our ultracold gas we can create condensates consisting of pairs of correlated atoms. These experiments introduce the ability to access the intriguing crossover regime where the quantum behavior of fermions becomes intertwined with that of bosons.

X. Q. Huang

Based on the real-space Mott insulator model, we establish a unifiedpairing, coherent and condensate mechanism of superconductivity. Motivatedby Dirac's magnetic monopole and Maxwell's displacement current hypothesis,we demonstrate that electric and magnetic fields are intrinsicallyrelevant. An isolated proton or electron creates an electric field,whereas a quantized proton-electron pair creates a magnetic field.The electric dipole vector of the proton-electron pair is the Ginzburg-Landauorder parameter in the superconducting phase transition. The Pierce-likedimerization pairing transition of the electron-proton electric dipolelattice leads to the symmetry breaking of the Mott insulating stateand the emergence of superconducting and magnetic states. This theoreticalframework can comprehensively explain all superconducting phenomena.Our research sheds new light on electron spin, magnetic monopoles,and the symmetry of Maxwell's equations.