Eric A. Cornell

Observation of bose-einstein condensation in a dilute atomic vapor.

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 1012 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.

Dynamics of component separation in a binary mixture of Bose-Einstein condensates

We describe the first experiments that study in a controlled way the dynamics of distinguishable and interpenetrating bosonic quantum fluids. We work with a two-component system of Bose-Einstein condensates in the

Stable (85)Rb Bose-Einstein Condensates with Widely Tunable Interactions

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Dynamics of collapsing and exploding Bose–Einstein condensates

and

Watching Dark Solitons Decay into Vortex Rings in a Bose-Einstein Condensate

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Measurements of Relative Phase in Two-Component Bose-Einstein Condensates

spin states of

Controlled Collapse of a Bose-Einstein Condensate

{}^{87}\mathrm{Rb}

Measurement of the Temperature Dependence of the Casimir-Polder Force

. The two condensates are created with complete spatial overlap, and in subsequent evolution they undergo complex relative motions that tend to preserve the total density profile. The motions quickly damp out, leaving the condensates in a steady state with a non-negligible (and adjustable) overlap region.

Rapidly Rotating Bose-Einstein Condensates in and near the Lowest Landau Level

Bose-Einstein condensation has been achieved in a magnetically trapped sample of 85Rb atoms. Long-lived condensates of up to 10(4) atoms have been produced by using a magnetic-field-induced Feshbach resonance to reverse the sign of the scattering length. This system provides new opportunities for the study of condensate physics. The variation of the scattering length near the resonance has been used to magnetically tune the condensate self-interaction energy over a wide range, extending from strong repulsive to large attractive interactions. When the interactions were switched from repulsive to attractive, the condensate shrank to below our resolution limit, and after approximately 5 ms emitted a burst of high-energy atoms.

Driving Bose-Einstein-Condensate Vorticity with a Rotating Normal Cloud

When atoms in a gas are cooled to extremely low temperatures, they will—under the appropriate conditions—condense into a single quantum-mechanical state known as a Bose–Einstein condensate. In such systems, quantum-mechanical behaviour is evident on a macroscopic scale. Here we explore the dynamics of how a Bose–Einstein condensate collapses and subsequently explodes when the balance of forces governing its size and shape is suddenly altered. A condensates equilibrium size and shape is strongly affected by the interatomic interactions. Our ability to induce a collapse by switching the interactions from repulsive to attractive by tuning an externally applied magnetic field yields detailed information on the violent collapse process. We observe anisotropic atom bursts that explode from the condensate, atoms leaving the condensate in undetected forms, spikes appearing in the condensate wavefunction and oscillating remnant condensates that survive the collapse. All these processes have curious dependences on time, on the strength of the interaction and on the number of condensate atoms. Although the system would seem to be simple and well characterized, our measurements reveal many phenomena that challenge theoretical models.