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A purely dipolar quantum gas
| Content Provider | Semantic Scholar |
|---|---|
| Author | Metz, Jonas Koch, Tino Fröhlich, Bernd Griesmaier, Axel Pfau, Tilman |
| Copyright Year | 2008 |
| Abstract | In usual experiments with BECs, the only relevant interacti on is the isotropic and shortrange contact interaction, which is described by a single pa rameter, the scattering length a. In contrast, the dipole–dipole interaction between parti cles possessing an electric or magnetic dipole moment is of long range character and anisot ropic, which gives rise to new phenomena 1. Most prominently, the stability of a dipolar BEC depends not only on the value of the scattering lengtha, but also strongly on the geometry of the external trapping p otential. Here, we report on the experimental investigation of the sta bility of a dipolar BEC ofCr as a function of the scattering length and the trap aspect rat io. We find good agreement with a universal stability threshold arising from a simple theor etical model. Using a pancakeshaped trap with the dipoles oriented along the short axis of the trap, we are able to tune the scattering length to zero, stabilizing a purely dipolar quantum gas2. We also experimentally investigated the collapse dynamics of a dipolar condensate of Cr atoms when the s-wave scattering length characterizing t he contact interaction is reduced below a critical value. A complex dynamics, involving an anisotropic, d-wave symmetric explosion of the condensate, was observed on time sca l s significantly shorter than the trap period. At the same time, the condensate atom number decreases abruptly during the collapse. We compare our experimental results with n umerical simulations of the three-dimensional Gross-Pitaevskii equation, including the contact and dipolar interactions as well as three-body losses (see Fig.1). The simulations in dicate that the collapse is accompanied by the formation of two vortex rings with opposite c rculations. 3. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.phys.uconn.edu/icap2008/invited/icap2008-pfau.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/0808.3876v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Arabic numeral 0 Battery eliminator circuit Chromium Complex dynamics Experiment GAS2 wt Allele Interaction List of Code Lyoko episodes Optic axis of a crystal Ring device STA-MCA Bypass Scattering length Simulation Trap (computing) Vortex liter/second |
| Content Type | Text |
| Resource Type | Article |
