@article{JaphaZhouKeiletal.2016,
  author    = {Japha, Yonathan and Zhou, Shuyu and Keil, Mark and Folman, Ron and Henkel, Carsten and Vardi, Amichay},
  title     = {Suppression and enhancement of decoherence in an atomic Josephson junction},
  series = {NEW JOURNAL OF PHYSICS},
  volume    = {18},
  journal   = {NEW JOURNAL OF PHYSICS},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/18/5/055008},
  pages     = {22},
  year      = {2016},
  abstract  = {We investigate the role of interatomic interactions when a Bose gas, in a double-well potential with a finite tunneling probability (a 'Bose-Josephson junction'), is exposed to external noise. We examine the rate of decoherence of a system initially in its ground state with equal probability amplitudes in both sites. The noise may induce two kinds of effects: firstly, random shifts in the relative phase or number difference between the two wells and secondly, loss of atoms from the trap. The effects of induced phase fluctuations are mitigated by atom-atom interactions and tunneling, such that the dephasing rate may be suppressed by half its single-atom value. Random fluctuations may also be induced in the population difference between the wells, in which case atom-atom interactions considerably enhance the decoherence rate. A similar scenario is predicted for the case of atom loss, even if the loss rates from the two sites are equal. We find that if the initial state is number-squeezed due to interactions, then the loss process induces population fluctuations that reduce the coherence across the junction. We examine the parameters relevant for these effects in a typical atom chip device, using a simple model of the trapping potential, experimental data, and the theory of magnetic field fluctuations near metallic conductors. These results provide a framework for mapping the dynamical range of barriers engineered for specific applications and set the stage for more complex atom circuits ('atomtronics').},
  language  = {en}
}
@article{DialloHenkel2015,
  author    = {Diallo, Abdoulaye and Henkel, Carsten},
  title     = {Excitations at the border of a condensate},
  series = {Journal of physics : B, Atomic, molecular and optical physics},
  volume    = {48},
  journal   = {Journal of physics : B, Atomic, molecular and optical physics},
  number    = {16},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0953-4075},
  doi       = {10.1088/0953-4075/48/16/165302},
  pages     = {14},
  year      = {2015},
  abstract  = {We solve the Bogoliubov equations for an inhomogeneous condensate in the vicinity of a linear turning point. A stable integration scheme is developed using a transformation into an adiabatic basis. We identify boundary modes trapped in a potential whose shape is similar to a Hartree-Fock mean-field treatment. These modes are non-resonantly excited when bulk modes reflect at the turning point and contribute significantly to the spectrum of local density fluctuations.},
  language  = {en}
}