scholarly journals Scattering Length Instability in Dipolar Bose-Einstein Condensates

2006 ◽  
Vol 97 (16) ◽  
Author(s):  
D. C. E. Bortolotti ◽  
S. Ronen ◽  
J. L. Bohn ◽  
D. Blume
Keyword(s):  
Scattering Length ◽  
Bose Einstein

scholarly journals Effective Potential for Ultracold Atoms at the Zero Crossing of a Feshbach Resonance

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
N. T. Zinner
Keyword(s):  
Effective Potential ◽  
Feshbach Resonance ◽  
Cold Atoms ◽  
Particle Number ◽  
Scattering Length ◽  
Order Effect ◽  
Effective Range ◽  
Effective Range Expansion ◽  
Zero Crossing ◽  
Bose Einstein

We consider finite-range effects when the scattering length goes to zero near a magnetically controlled Feshbach resonance. The traditional effective-range expansion is badly behaved at this point, and we therefore introduce an effective potential that reproduces the full T-matrix. To lowest order the effective potential goes as momentum squared times a factor that is well defined as the scattering length goes to zero. The potential turns out to be proportional to the background scattering length squared times the background effective range for the resonance. We proceed to estimate the applicability and relative importance of this potential for Bose-Einstein condensates and for two-component Fermi gases where the attractive nature of the effective potential can lead to collapse above a critical particle number or induce instability toward pairing and superfluidity. For broad Feshbach resonances the higher order effect is completely negligible. However, for narrow resonances in tightly confined samples signatures might be experimentally accessible. This could be relevant for suboptical wavelength microstructured traps at the interface of cold atoms and solid-state surfaces.

BOSE-EINSTEIN CONDENSATION OF ATOMS WITH ATTRACTIVE INTERACTION

1999 ◽  
Vol 13 (05n06) ◽  
pp. 625-631 ◽  
Author(s):  
N. AKHMEDIEV ◽  
M. P. DAS ◽  
A. V. VAGOV
Keyword(s):  
Statistical Physics ◽  
Scattering Length ◽  
Stationary Solutions ◽  
Attractive Potential ◽  
Einstein Condensation ◽  
Pitaevskii Equation ◽  
Bose Einstein Condensation ◽  
Three Body ◽  
Negative Scattering Length ◽  
Bose Einstein

We suggest that crucial effect on Bose-Einstein condensation in systems with attractive potential is three-body interaction. We investigate stationary solutions of the Gross-Pitaevskii equation with negative scattering length and a higher-order stabilising term in presence of an external parabolic potential. Stability properties of the condensate are similar to those for thermodynamic systems in statistical physics which have first order phase transitions. We have shown that there are three possible type of stationary solutions corresponding to stable, metastable and unstable phases. Results are discussed in relation to recently observed 7 Li condensate.

scholarly journals Periodically and quasi-periodically driven dynamics of Bose-Einstein condensates

2020 ◽  
Vol 9 (5) ◽  
Author(s):  
Pengfei Zhang ◽  
Yingfei Gu
Keyword(s):  
Phase Boundary ◽  
Quantum Dynamics ◽  
Scattering Length ◽  
Finite Measure ◽  
Sine Wave ◽  
Square Wave ◽  
Periodically Driven ◽  
Two Phases ◽  
Almost All ◽  
Bose Einstein

We study the quantum dynamics of Bose-Einstein condensates when the scattering length is modulated periodically or quasi-periodically in time within the Bogoliubov framework. For the periodically driven case, we consider two protocols where the modulation is a square-wave or a sine-wave. In both protocols for each fixed momentum, there are heating and non-heating phases, and a phase boundary between them. The two phases are distinguished by whether the number of excited particles grows exponentially or not. For the quasi-periodically driven case, we again consider two protocols: the square-wave quasi-periodicity, where the excitations are generated for almost all parameters as an analog of the Fibonacci-type quasi-crystal; and the sine-wave quasi-periodicity, where there is a finite measure parameter regime for the non-heating phase. We also plot the analogs of the Hofstadter butterfly for both protocols.

scholarly journals Bose-Einstein Condensation of Confined Atomic Gases at Ultra Low Temperatures

2017 ◽  
Vol 9 (5) ◽  
pp. 96
Author(s):  
M. Serhan
Keyword(s):  
Low Temperatures ◽  
Chemical Potential ◽  
Scattering Length ◽  
Einstein Condensation ◽  
Pitaevskii Equation ◽  
Atomic Gases ◽  
Bose Einstein Condensation ◽  
Gaussian Type ◽  
Negative Scattering Length ◽  
Bose Einstein

In this work I solve the Gross-Pitaevskii equation describing an atomic gas confined in an isotropic harmonic trap by introducing a variational wavefunction of Gaussian type. The chemical potential of the system is calculated and the solutions are discussed in the weakly and strongly interacting regimes. For the attractive system with negative scattering length the maximum number of atoms that can be put in the condensate without collapse begins is calculated.

scholarly journals Collective excitation of a Bose-Einstein condensate by modulation of the atomic scattering length

2010 ◽  
Vol 81 (5) ◽  
Author(s):  
S. E. Pollack ◽  
D. Dries ◽  
R. G. Hulet ◽  
K. M. F. Magalhães ◽  
E. A. L. Henn ◽  
...  
Keyword(s):  
Collective Excitation ◽  
Scattering Length ◽  
Einstein Condensate ◽  
Bose Einstein Condensate ◽  
Atomic Scattering ◽  
Bose Einstein
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