Suppression of collision-induced dephasing by periodic, erratic, or noisy driving

Khripkov, Christine; Vardi, Amichay; Cohen, Doron

doi:10.1140/epjst/e2013-01771-9

Cited by 2 publications

(2 citation statements)

References 25 publications

(47 reference statements)

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“…Semiclassically, for any Gaussian phase-space distribution, the one-particle coherence is related to the variances ∆ a , ∆ b of the distribution along its principal axes a, b as [24]…”

Section: F Coherencementioning

confidence: 99%

“…For example, the master equation generated by the dissipative term of Eq. ( 36) can be represented by adding a term f 3 (t) Ŝ3 to the Hamiltonian where f (t) is an erratic driving amplitude (a random process with zero average and short correlation time [24]). This may be viewed as a realization of a Markovian stochastic process such that upon averaging,…”

Section: A Number Conserving Noise (No Loss)mentioning

confidence: 99%

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Suppression and enhancement of decoherence in an atomic Josephson junction

et al. 2016

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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'). Figure 4. Decoherence induced by loss. A loss rate g = J 0.08 loss is applied, such that after = t J 10 only ∼45% of the atoms are left in the trap. During this time the coherence drops due to interactions. We have used N=50 atoms in the numerical simulation, showing two curves, for onsite interaction strengths = U J 0.2 [u = 10] and U=J [u = 50]. (a) coherence as a function of time. (b) instantaneous rate of decoherence, showing oscillations with half the Josephson period w = ( J 3.32 J and J 7.14 for the two curves).

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“…Semiclassically, for any Gaussian phase-space distribution, the one-particle coherence is related to the variances ∆ a , ∆ b of the distribution along its principal axes a, b as [24]…”

Section: F Coherencementioning

confidence: 99%

Section: A Number Conserving Noise (No Loss)mentioning

confidence: 99%

Suppression and enhancement of decoherence in an atomic Josephson junction

et al. 2016

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Stability and stabilization of unstable condensates

Cohen¹

2015

Phys. Scr.

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It is possible to condense a macroscopic number of bosons into a single mode. Adding interactions the question arises whether the condensate is stable. For repulsive interaction the answer is positive with regard to the ground-state, but what about a condensation in an excited mode? We discuss some results that have been obtained for a 2-mode bosonic Josephson junction, and for a 3-mode minimal-model of a superfluid circuit. Additionally we mention the possibility to stabilize an unstable condensate by introducing periodic or noisy driving into the system: this is due to the Kapitza and the Zeno effects.

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Suppression of collision-induced dephasing by periodic, erratic, or noisy driving

Cited by 2 publications

References 25 publications

Suppression and enhancement of decoherence in an atomic Josephson junction

Suppression and enhancement of decoherence in an atomic Josephson junction

Stability and stabilization of unstable condensates

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