Abstract
Neutral fermions present new opportunities for testing models of many-body quantum systems, realizing precision atom interferometry, producing ultra-cold molecules, and investigating fundamental forces. However, since they were first observed1, quantum degenerate Fermi gases (DFGs) have continued to be challenging to produce, and have been realized in only a handful of laboratories2,3,4,5,6,7,8,9,10. In this letter, we report the production of a DFG using a simple apparatus based on a microfabricated magnetic trap. Similar approaches applied to Bose–Einstein condensation of 87Rb (refs 11,12) have accelerated evaporative cooling and eliminated the need for multiple vacuum chambers. We demonstrate sympathetic cooling for the first time in a microtrap, and cool 40K to Fermi degeneracy in just six seconds—faster than has been possible in conventional magnetic traps. To understand our sympathetic cooling trajectory, we measure the temperature dependence of the 40 K–87Rb cross-section and observe its Ramsauer–Townsend reduction.
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References
DeMarco, B. & Jin, D. S. Onset of Fermi degeneracy in a trapped atomic gas. Science 285, 1703–1706 (1999).
Truscott, A. G., Strecker, K. E., McAlexander, W. I., Partridge, G. B. & Hulet, R. G. Observation of Fermi pressure in a gas of trapped atoms. Science 291, 2570–2572 (2001).
Schreck, F. et al. Quasipure Bose-Einstein condensate immersed in a Fermi sea. Phys. Rev. Lett. 87, 080403 (2001).
Granade, S. R., Gehm, M. E., O’Hara, K. M. & Thomas, J. E. All-optical production of a degenerate Fermi gas. Phys. Rev. Lett. 88, 120405 (2002).
Hadzibabic, Z. et al. Two-species mixture of quantum degenerate Bose and Fermi gases. Phys. Rev. Lett. 88, 160401 (2002).
Roati, G., Riboli, F., Modugno, G. & Inguscio, M. Fermi–Bose quantum degenerate 40K-87Rb mixture with attractive interaction. Phys. Rev. Lett. 89, 150403 (2002).
Bartenstein, M. et al. Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas. Phys. Rev. Lett. 92, 120401 (2004).
Köhl, M., Moritz, H., Stöferle, T., Günter, K. & Esslinger, T. Fermionic atoms in a three dimensional optical lattice: observing Fermi surfaces, dynamics, and interactions. Phys. Rev. Lett. 94, 080403 (2005).
Silber, C. et al. Quantum-degenerate mixture of fermionic lithium and bosonic rubidium gases. Phys. Rev. Lett. 95, 170408 (2005).
Ospelkaus, C., Ospelkaus, S., Sengstock, K. & Bongs, K. Interaction-driven dynamics of 40K/87Rb Fermi–Bose gas mixtures in the large particle number limit. Phys. Rev. Lett. 96, 020401 (2006).
Hänsel, W., Hommelhoff, P., Hänsch, T. W. & Reichel, J. Bose-Einstein condensation on a microelectronic chip. Nature 413, 498–501 (2001).
Ott, H., Fortagh, J., Schlotterbeck, G., Grossmann, A. & Zimmermann, C. Bose-Einstein condensation in a surface microtrap. Phys. Rev. Lett. 87, 230401 (2001).
Groth, S. et al. Atom chips: Fabrication and thermal properties. Appl. Phys. Lett. 85, 2980–2982 (2004).
Thywissen, J. H., Westervelt, R. M. & Prentiss, M. Quantum point contacts for neutral atoms. Phys. Rev. Lett. 83, 3762–3765 (1999).
Wang, Y.-J. et al. Atom Michelson interferometer on a chip using a Bose-Einstein condensate. Phys. Rev. Lett. 94, 090405 (2005).
Aubin, S. et al. Trapping fermionic 40K and bosonic 87Rb in a chip trap. J. Low Temp. Phys. 140, 377–396 (2005).
Myatt, C. J., Burt, E. A., Ghrist, R. W., Cornell, E. A. & Wieman, C. E. Production of two overlapping Bose-Einstein condensates by sympathetic cooling. Phys. Rev. Lett. 78, 586–589 (1997).
Schreck, F. et al. Sympathetic cooling of bosonic and fermionic lithium gases towards quantum degeneracy. Phys. Rev. A 64, 011402 (2001).
Goldwin, J. et al. Measurement of the interaction strength in a Bose-Fermi mixture with 87Rb and 40K . Phys. Rev. A 70, 021601 (2004).
Ferlaino, F. et al. Feschbach spectroscopy of K-Rb atomic mixture. Phys. Rev. A 73, 040702 (2006).
van Kempen, E. G. M., Kokkelmans, S. J. J. M. F., Heinzen, J. J. & Verhaar, B. J. Interisotope determination of ultracold rubidium interactions from three high-precision experiments. Phys. Rev. Lett. 88, 93201 (2002).
Modugno, G. et al. Collapse of a degenerate Fermi gas. Science 297, 2240–2243 (2002).
Inouye, S. et al. Observation of heteronuclear Feshbach resonances in a mixture of bosons and fermions. Phys. Rev. Lett. 93, 183201 (2004).
Anderlini, M. et al. Sympathetic cooling and collisional properties of a Rb-Cs mixture. Phys. Rev. A 71, 061401 (2005).
Mosk, A. et al. Mixture of ultracold lithium and cesium atoms in an optical dipole trap. Appl. Phys. B 73, 791–799 (2001).
Flambaum, V. V., Gribakin, G. F. & Harabati, C. Analytical calculation of cold-atom scattering. Phys. Rev. A 59, 1998–2005 (1999).
Townsend, J. S. A Modern Approach to Quantum Mechanics 393 (McGraw-Hill, New York, 1992).
O’Hara, K. M. et al. Observation of a strongly interacting degenerate Fermi gas of atoms. Science 298, 2179–2182 (2002).
Busch, Th., Anglin, J. R., Cirac, J. I. & Zoller, P. Inhibition of spontaneous emission in Fermi gases. Europhys. Lett. 44, 1–6 (1998).
DeMarco, B. & Jin, D. S. Exploring a quantum degenerate gas of fermionic atoms. Phys. Rev. A 58, R4267–R4270 (1998).
Acknowledgements
We would like to thank D. Jin, J. Dalibard, J. Bohm, and D. Guery-Odelin for helpful conversations about scattering theory, and A. Simoni for sending us unpublished 40K–87Rb cross-section calculations. We also thank N. Bigelow, A. Aspect, T. Schumm, and H. Moritz for stimulating conversations, P. Bouyer and R. Nyman for providing a tapered amplifier used in this work, and J. Estève for fabricating the chip used in this work. This work is supported by the NSERC, CFI, OIT, PRO, CRC, and Research Corporation. S.A., L.J.L. and D.M. acknowledge support from NSERC. M.H.T.E. acknowledges support from OGS.
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Aubin, S., Myrskog, S., Extavour, M. et al. Rapid sympathetic cooling to Fermi degeneracy on a chip. Nature Phys 2, 384–387 (2006). https://doi.org/10.1038/nphys309
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DOI: https://doi.org/10.1038/nphys309
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