Publications Gerhard HENDL

2011

Article

• D. Naik, A. Trenkwalder, C. Kohstall, F. M. Spiegelhalder, M. Zaccanti, G. Hendl, F. Schreck, R. Grimm, T. Hanna, P. S. Julienne Feshbach resonances in the 6Li-40K Fermi-Fermi mixture: Elastic versus inelastic interactions., Eur. Phys. J. D 65 65 (2011-01-14), http://dx.doi.org/10.1140/epjd/e2010-10591-2 doi:10.1140/epjd/e2010-10591-2 (ID: 717466) Toggle Abstract
  We present a detailed theoretical and experimental study of Feshbach resonances in the 6Li-40K mixture. Particular attention is given to the inelastic scattering properties, which have not been considered before. As an important example, we thoroughly investigate both elastic and inelastic scattering properties of a resonance that occurs near 155 G. Our theoretical predictions based on a coupled channels calculation are found in excellent agreement with the experimental results. We also present theoretical results on the molecular state that underlies the 155G resonance, in particular concerning its lifetime against spontaneous dissociation. We then present a survey of resonances in the system, fully characterizing the corresponding elastic and inelastic scattering properties. This provides the essential information to identify optimum resonances for applications relying on interaction control in this Fermi-Fermi mixture.

2010

Article

• F. Spiegelhalder, A. Trenkwalder, D. Naik, G. Kerner, E. Wille, G. Hendl, F. Schreck, R. Grimm All-optical production of a degenerate mixture of 6Li and 40K and creation of heteronuclear molecules, Phys. Rev. A 81 043637 (2010), http://dx.doi.org/10.1103/PhysRevA.81.043637 doi:10.1103/PhysRevA.81.043637 (ID: 717108) Toggle Abstract
  We present the essential experimental steps of our all-optical approach to prepare a double-degenerate Fermi-Fermi mixture of 6Li and 40K atoms, which then serves as a starting point for molecule formation. We first describe the optimized trap loading procedures, the internal-state preparation of the sample, and the combined evaporative and sympathetic cooling process. We then discuss the preparation of the sample near an interspecies Feshbach resonance, and we demonstrate the formation of heteronuclear molecules by a magnetic field ramp across the resonance.
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2009

Article

• F. Spiegelhalder, A. Trenkwalder, D. Naik, G. Hendl, F. Schreck, R. Grimm Collisional stability of 40K immersed in a strongly interacting Fermi gas of 6Li, Phys. Rev. Lett. 103 223203 (2009-11-25), http://dx.doi.org/10.1103/PhysRevLett.103.223203 doi:10.1103/PhysRevLett.103.223203 (ID: 717096) Toggle Abstract
  We investigate the collisional stability of a sample of 40K atoms immersed in a tunable spin mixture of 6Li atoms. In this three-component Fermi-Fermi mixture, we find very low loss rates in a wide range of interactions as long as molecule formation of 6Li is avoided. The stable fermionic mixture with two resonantly interacting spin states of one species together with another species is a promising system for a broad variety of phenomena in few- and many-body quantum physics.
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2008

Article

• E. Wille, F. Spiegelhalder, G. Kerner, D. Naik, A. Trenkwalder, G. Hendl, F. Schreck, R. Grimm, T. Tiecke, J. T. Walraven, S. J. Kokkelmans, E. Tiesinga, P. S. Julienne Exploring an Ultracold Fermi-Fermi Mixture: Interspecies Feshbach Resonances and Scattering Properties of 6Li and 40K, Phys. Rev. Lett. 100 053201 (2008), http://dx.doi.org/10.1103/PhysRevLett.100.053201 doi:10.1103/PhysRevLett.100.053201 (ID: 559392) Toggle Abstract
  We report on the observation of Feshbach resonances in an ultracold mixture of two fermionic species, 6Li and 40K. The experimental data are interpreted using a simple asymptotic bound state model and full coupled channels calculations. This unambiguously assigns the observed resonances in terms of various s- and p-wave molecular states and fully characterizes the ground-state scattering properties in any combination of spin states.
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2003

Articles

• S. Jochim, M. Bartenstein, A. Altmeyer, G. Hendl, S. Riedl, C. Chin, J. Hecker Denschlag, R. Grimm Bose-Einstein Condensation of Molecules, Science 302 2103 (2003-12-19), http://dx.doi.org/10.1126/science.1093280 doi:10.1126/science.1093280 (ID: 336833) Toggle Abstract
  We report on the Bose-Einstein condensation of more than 105 Li2 molecules in an optical trap starting from a spin mixture of fermionic lithium atoms. During forced evaporative cooling, the molecules are formed by three-body recombination near a Feshbach resonance and finally condense in a long-lived thermal equilibrium state. We measured the characteristic frequency of a collective excitation mode and demonstrated the magnetic field–dependent mean field by controlled condensate spilling.
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• S. Jochim, M. Bartenstein, A. Altmeyer, G. Hendl, C. Chin, J. Hecker Denschlag, R. Grimm Pure Gas of Optically Trapped Molecules Created from Fermionic Atoms, Phys. Rev. Lett. 91 240402 (2003-12-08), http://dx.doi.org/10.1103/PhysRevLett.91.240402 doi:10.1103/PhysRevLett.91.240402 (ID: 336841) Toggle Abstract
  We report on the production of a pure sample of up to 3x10^5 optically trapped molecules from a Fermi gas of 6Li atoms. The dimers are formed by three-body recombination near a Feshbach resonance. For purification a Stern-Gerlach selection technique is used that efficiently removes all trapped atoms from the atom-molecule mixture. The behavior of the purified molecular sample shows a striking dependence on the applied magnetic field. For very weakly bound molecules near the Feshbach resonance, the gas exhibits a remarkable stability with respect to collisional decay.
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Dissertation

• G. Hendl Atom - Atom Wechselwirkung in einem ultrakalten, fermionischen Gas, (2003-09-00), (ID: 343684)

2002

Article

• S. Jochim, M. Bartenstein, G. Hendl, J. Hecker Denschlag, R. Grimm, A. Mosk, M. Weidemüller Magnetic Field Control of Elastic Scattering in a Cold Gas of Fermionic Lithium Atoms, Phys. Rev. Lett. 89 273202 (2002-12-18), http://dx.doi.org/10.1103/PhysRevLett.89.273202 doi:10.1103/PhysRevLett.89.273202 (ID: 337849) Toggle Abstract
  We study elastic collisions in an optically trapped spin mixture of fermionic lithium atoms in the presence of magnetic fields up to 1.5kG by measuring evaporative loss. Our experiments confirm the expected magnetic tunability of the scattering length by showing the main features of elastic scattering according to recent calculations. We measure the zero crossing of the scattering length that is associated with a predicted Feshbach resonance at 530(3)G. Beyond the resonance we observe the expected large cross section in the triplet scattering regime.