Symmetry-breaking interactions have a crucial role in many areas of physics, ranging from classical ferrofluids to superfluid 3He and d-wave superconductivity. For superfluid quantum gases, a variety of new physical phenomena arising from the symmetry-breaking interaction between electric or magnetic dipoles are expected1. Novel quantum phases in optical lattices, such as chequerboard or supersolid phases, are predicted for dipolar bosons2,3. Dipolar interactions can also enrich considerably the physics of quantum gases with internal degrees of freedom4,5,6. Arrays of dipolar particles could be used for efficient quantum information processing7. Here we report the realization of a chromium Bose–Einstein condensate with strong dipolar interactions. By using a Feshbach resonance, we reduce the usual isotropic contact interaction, such that the anisotropic magnetic dipole–dipole interaction between 52Cr atoms becomes comparable in strength. This induces a change of the aspect ratio of the atom cloud; for strong dipolar interactions, the inversion of ellipticity during expansion (the usual ‘smoking gun’ evidence for a Bose–Einstein condensate) can be suppressed. These effects are accounted for by taking into account the dipolar interaction in the superfluid hydrodynamic equations governing the dynamics of the gas, in the same way as classical ferrofluids can be described by including dipolar terms in the classical hydrodynamic equations. Our results are a first step in the exploration of the unique properties of quantum ferrofluids.
This is a preview of subscription content, access via your institution
Open Access articles citing this article.
Scientific Reports Open Access 16 March 2020
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Baranov, M., Dobrek, Ł., Góral, K., Santos, L. & Lewenstein, M. Ultracold dipolar gases — a challenge for experiments and theory. Phys. Scr. T102, 74–81 (2002)
Góral, K., Santos, L. & Lewenstein, M. Quantum phases of dipolar bosons in optical lattices. Phys. Rev. Lett. 88, 170406 (2002)
Menotti, C., Trefzger, C. & Lewenstein, M. Metastable states of a gas of dipolar bosons in a 2D optical lattice. Phys. Rev. Lett. 98, 235301 (2007)
Kawaguchi, Y., Saito, H. & Ueda, M. Einstein–de Haas effect in dipolar Bose-Einstein condensates. Phys. Rev. Lett. 96, 080405 (2006)
Santos, L. & Pfau, T. Spin-3 chromium Bose-Einstein condensates. Phys. Rev. Lett. 96, 190404 (2006)
Yi, S. & Pu, H. Spontaneous spin textures in dipolar spinor condensates. Phys. Rev. Lett. 97, 020401 (2006)
DeMille, D. Quantum computation with trapped polar molecules. Phys. Rev. Lett. 88, 067901 (2002)
Doyle, J., Friedrich, B., Krems, R. V. & Masnou-Seeuws, F. Special issue on ultracold molecules. Eur. Phys. J. D 31, 149–445 (2004)
Köhler, T., Góral, K. & Julienne, P. S. Production of cold molecules via magnetically tunable Feshbach resonances. Rev. Mod. Phys. 78, 1311–1361 (2006)
Ospelkaus, C. et al. Ultracold heteronuclear molecules in a 3D optical lattice. Phys. Rev. Lett. 97, 120402 (2006)
Sage, J., Sainis, S., Bergeman, T. & DeMille, D. Optical production of ultracold polar molecules. Phys. Rev. Lett. 94, 203001 (2005)
Marinescu, M. & You, L. Controlling atom-atom interaction at ultralow temperatures by dc electric fields. Phys. Rev. Lett. 81, 4596–4599 (1998)
Giovanazzi, S., O’Dell, D. & Kurizki, G. Density modulations of Bose-Einstein condensates via laser-induced interactions. Phys. Rev. Lett. 88, 130402 (2002)
Griesmaier, A., Werner, J., Hensler, S., Stuhler, J. & Pfau, T. Bose-Einstein condensation of chromium. Phys. Rev. Lett. 94, 160401 (2005)
Griesmaier, A. et al. Comparing contact and dipolar interactions in a Bose-Einstein condensate. Phys. Rev. Lett. 97, 250402 (2006)
Stuhler, J. et al. Observation of dipole-dipole interaction in a degenerate quantum gas. Phys. Rev. Lett. 95, 150406 (2005)
Werner, J., Griesmaier, A., Hensler, S., Stuhler, J. & Pfau, T. Observation of Feshbach resonances in an ultracold gas of 52Cr. Phys. Rev. Lett. 94, 183201 (2005)
Giovanazzi, S. et al. Expansion dynamics of a dipolar Bose-Einstein condensate. Phys. Rev. A 74, 013621 (2006)
Inouye, S. et al. Observation of Feshbach resonances in a Bose-Einstein condensate. Nature 392, 151–154 (1998)
Stenger, J. et al. Strongly enhanced inelastic collisions in a Bose-Einstein condensate near Feshbach resonances. Phys. Rev. Lett. 82, 2422–2425 (1999)
Santos, L., Shlyapnikov, G. V., Zoller, P. & Lewenstein, M. Bose-Einstein condensation in trapped dipolar gases. Phys. Rev. Lett. 85, 1791–1794 (2000)
Góral, K., Rza̧żewski, K. & Pfau, T. Bose-Einstein condensation with magnetic dipole-dipole forces. Phys. Rev. A 61, 051601(R) (2000)
Dutta, O. & Meystre, P. Ground-state structure and stability of dipolar condensates in anisotropic traps. Phys. Rev. A 75, 053604 (2007)
Ronen, S., Bortolotti, D. C. E. & Bohn, J. L. Radial and angular rotons in trapped dipolar gases. Phys. Rev. Lett. 98, 030406 (2007)
Santos, L., Shlyapnikov, G. V. & Lewenstein, M. Roton-maxon spectrum and stability of trapped dipolar Bose-Einstein condensates. Phys. Rev. Lett. 90, 250403 (2003)
Sasaki, S., Ishiguro, R., Caupin, F., Maris, H. J. & Balibar, S. Superfluidity of grain boundaries and supersolid behavior. Science 313, 1098–1100 (2006)
We thank L. Santos for discussions and J. Stuhler for contributions in the initial phases of the experiment. We acknowledge financial support by the German Science Foundation (SFB/TRR21) and the EU (Marie-Curie fellowship to T.L.).
Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.
About this article
Cite this article
Lahaye, T., Koch, T., Fröhlich, B. et al. Strong dipolar effects in a quantum ferrofluid. Nature 448, 672–675 (2007). https://doi.org/10.1038/nature06036
This article is cited by
Nature Physics (2021)
International Journal of Theoretical Physics (2021)
Scientific Reports (2020)
International Journal of Theoretical Physics (2019)
International Journal of Theoretical Physics (2018)