Journal ArticleDOI
Observation of Bose-Einstein Condensation in a Dilute Atomic Vapor
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TLDR
A Bose-Einstein condensate was produced in a vapor of rubidium-87 atoms that was confined by magnetic fields and evaporatively cooled and exhibited a nonthermal, anisotropic velocity distribution expected of the minimum-energy quantum state of the magnetic trap in contrast to the isotropic, thermal velocity distribution observed in the broad uncondensed fraction.Abstract:
A Bose-Einstein condensate was produced in a vapor of rubidium-87 atoms that was confined by magnetic fields and evaporatively cooled. The condensate fraction first appeared near a temperature of 170 nanokelvin and a number density of 2.5 x 10 12 per cubic centimeter and could be preserved for more than 15 seconds. Three primary signatures of Bose-Einstein condensation were seen. (i) On top of a broad thermal velocity distribution, a narrow peak appeared that was centered at zero velocity. (ii) The fraction of the atoms that were in this low-velocity peak increased abruptly as the sample temperature was lowered. (iii) The peak exhibited a nonthermal, anisotropic velocity distribution expected of the minimum-energy quantum state of the magnetic trap in contrast to the isotropic, thermal velocity distribution observed in the broad uncondensed fraction.read more
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Magnetic Trapping of Atomic Chromium and Molecular Calcium Monohydride
Abstract: In this thesis, I describe two trapping experiments: the magnetic trapping of atomic chromium and the magnetic trapping of molecular calcium monohydride. Experimental work with molecular vanadium monoxide will also be discussed. Building on previous work trapping atomic europium, the calcium monohydride experiment was a successful demonstration of the feasibility of magnetically trapping a neutral molecule. We studied the dynamics of our molecular cooling and trapping techniques. In addition, cold molecule-atom interactions were explored in the CaH– He system at sub-Kelvin temperatures. VO was employed in our first attempt, which failed, to magnetically trap a molecule. The reasons for the experiment’s failure were investigated, and various properties of VO measured at low temperatures. The chromium experiment was designed to cool trapped chromium atoms with the goal of creating a coexisting Bose-Einstein condensate and degenerate Fermi gas. The experimental plan was to use buffer-gas loading to magnetically trap large numbers of fermion and boson isotopes of chromium, and then use evaporative cooling to increase the phase space density until degeneracy was reached. Although we have not yet reached quantum degeneracy, we were able to trap and evaporatively cool both desired isotopes simultaneously and measure relevant chromium–chromium collisional properties. These results illuminate some of the broader issues involved with our cryogenics-based experimental techniques.
Journal ArticleDOI
Algebraic Bethe ansatz and tensor networks
TL;DR: This work applies the tools of tensor-network states to describe the eigenstates approximately as matrix product states, and obtains observables like the structure factor, dimer-dimer correlation functions, chiral correlated functions, and one-particle Green function directly.
Journal ArticleDOI
Elastic scattering of cold caesium and rubidium atoms
TL;DR: For elastic scattering of 133Cs atoms by 85Rb and 87Rb atoms, interacting via the X 1 Σ+ and a 3Σ+ molecular states of RbCs, calculations are presented of the scattering length and the effective range and also of two volume parameters, one for low energy p-wave scattering and one for the energy of an ensemble of fermions.
Dissertation
Coherent manipulation of ultracold atoms an atom chips
TL;DR: In this paper, the effect of the atom chip surface on internal-state coherence was investigated and a chip-based atomic clock was demonstrated, achieving a relative frequency stability of 1.7 × 10−11 (τ [s])−1/2.
Journal ArticleDOI
Geometric resonances in Bose?Einstein condensates with two- and three-body interactions
TL;DR: Vidanovi et al. as discussed by the authors investigated geometric resonances in Bose?Einstein condensates by solving the underlying time-dependent Gross?Pitaevskii equation for systems with two-and three-body interactions in an axially symmetric harmonic trap.
References
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Proceedings Article
Bose-Einstein condensation in a gas of sodium atoms
TL;DR: The striking signature of Bose condensation was the sudden appearance of a bimodal velocity distribution below the critical temperature of ~2µK.
Journal ArticleDOI
Trapping of neutral sodium atoms with radiation pressure
TL;DR: The confinement and cooling of an optically dense cloud of neutral sodium atoms by radiation pressure was reported, provided by three retroreflected laser beams propagating along orthogonal axes, with a weak magnetic field used to distinguish between the beams.
Journal ArticleDOI
Plancks Gesetz und Lichtquantenhypothese
TL;DR: In this article, the authors describe how the Phasenraum eines Lichtquants in bezug auf ein gegebenes Volumen wird in „Zellen“ von der Grose h3 aufgeteilt, i.e., the Zahl der moglichen Verteilungen der Lichtquanten einer makroskopisch definierten Strahlung unter diese Zellen liefert die Entropie.
Journal ArticleDOI
Observation of atoms laser cooled below the Doppler limit
Paul D. Lett,Richard N. Watts,Christoph I Westbrook,William D. Phillips,Phillip L. Gould,Harold Metcalf +5 more
TL;DR: This "Doppler cooling limit" results from the minimization of the detuning-dependent temperature at low laser power1.
Journal ArticleDOI
Output Coupler for Bose-Einstein Condensed Atoms
TL;DR: In this paper, an output coupler for Bose condensed atoms in a magnetic trap was demonstrated, where short pulses of rf radiation were used to create Bose condensates in a superposition of trapped and untrapped hyperfine states.