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
Citations
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Bose-Einstein condensation with a BCS model interaction
TL;DR: A simple model of a boson-fermion mixture of unpaired fermions plus linear dispersion-relation Cooper pairs that includes pair-breaking effects leads to Bose-Einstein condensation for dimensions greater than unity, at critical temperatures substantially greater than those of the BCS theory of superconductivity.
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Cold atom trap with zero residual magnetic field: the ac magneto-optical trap.
TL;DR: A novel atom trap is described using alternating current to generate the magnetic B field, together with high speed polarization switching of the damping laser field, which produces a trap as effective as a standard magneto-optical trap, with the advantage that the average B field is zero.
Journal ArticleDOI
Variational methods with coupled Gaussian functions for Bose-Einstein condensates with long-range interactions. II. Applications
TL;DR: In this paper, the authors demonstrate that coupled Gaussian wave packets are a full-fledged alternative to direct numerical solutions of the Gross-Pitaevskii equation, or even superior.
Journal ArticleDOI
Excitation spectra of many-body systems by linear response: General theory and applications to trapped condensates
Julian Grond,Alexej I. Streltsov,Axel U. J. Lode,Kaspar Sakmann,Lorenz S. Cederbaum,Ofir E. Alon +5 more
TL;DR: In this paper, the authors derived a general linear-response many-body theory capable of computing excitation spectra of trapped interacting bosonic systems, e.g., depleted and fragmented Bose-Einstein condensates (BECs).
Journal ArticleDOI
Variational study of dilute Bose condensate in a harmonic trap
TL;DR: In this article, a two-parameter trial condensate wave function is used to find an approximate variational solution to the Gross-Pitaevskii equation for N 0 condensed bosons in an isotropic harmonic trap with oscillator lengthd0 and interacting through a repulsive two-body scattering lengtha>0.
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.
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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.
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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.
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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.
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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.