We have observed Bose-Einstein condensation of sodium atoms. The atoms were trapped in a novel trap that employed both magnetic and optical forces. Evaporative cooling increased the phase-space density by 6 orders magnitude within seven seconds. Condensates contained up to 5\ifmmode\times\else\texttimes\fi{}${10}^{5}$ at densities exceeding ${10}^{14}$ ${\mathrm{cm}}^{\ensuremath{-}3}$. striking signature Bose was sudden appearance bimodal velocity distribution below critical temperature...

Interference between two freely expanding Bose-Einstein condensates has been observed. Two separated by ∼40 micrometers were created evaporatively cooling sodium atoms in a double-well potential formed magnetic and optical forces. High-contrast matter-wave interference fringes with period of ∼15 observed after switching off the letting expand for 40 milliseconds overlap. This demonstrates that Bose condensed are “laser-like”; is, they coherent show long-range correlations. These results have...

Bose-Einstein condensates of sodium atoms have been confined in an optical dipole trap using a single focused infrared laser beam. This eliminates the restrictions magnetic traps for further studies atom lasers and condensates. More than $5\ifmmode\times\else\texttimes\fi{}{10}^{6}$ condensed were transferred into trap. Densities up to $3\ifmmode\times\else\texttimes\fi{}{10}^{15}{\mathrm{cm}}^{\ensuremath{-}3}$ Bose obtained, allowing measurement three-body loss rate constant as...

Spinor Bose gases form a family of quantum fluids manifesting both magnetic order and superfluidity. This article reviews experimental theoretical progress in understanding the static dynamic properties these fluids. The connection between system rotational symmetry atomic states their interactions are investigated. Following review techniques used for characterizing spinor gases, mean-field many-body ground states, isolation under application symmetry-breaking external fields, discussed....

We have demonstrated an output coupler for Bose condensed atoms in a magnetic trap. Short pulses of rf radiation were used to create condensates superposition trapped and untrapped hyperfine states. The fraction out-coupled was adjusted between 0% 100% by varying the amplitude radiation. This configuration produces coherent can be regarded as pulsed ``atom laser.''

Properties of a Bose-Einstein condensate were studied by stimulated, two-photon Bragg scattering. The high momentum and energy resolution this method allowed spectroscopic measurement the mean-field intrinsic uncertainty condensate. coherence length was shown to be equal its size. spectroscopy can used determine dynamic structure factor over wide range transfers.

Collective excitations of a dilute Bose condensate have been observed. These are analogous to phonons in superfluid helium. condensates were created by evaporatively cooling magnetically trapped sodium atoms. Excitations induced modulation the trapping potential, and detected as shape oscillations freely expanding condensates. The frequencies lowest modes agreed well with theoretical predictions based on mean-field theory. Before onset Bose-Einstein condensation, we observed sound waves...

Rayleigh scattering off a Bose-Einstein condensate was studied. Exposing an elongated to single off-resonant laser beam resulted in the observation of highly directional light and atoms. This collective is caused by coherent center-of-mass motion atoms condensate. A recoiling built up matter wave amplification.

Bose-Einstein condensation of sodium atoms has been observed in a novel ``cloverleaf'' trap. This trap combines tight confinement with excellent optical access, using only dc electromagnets. Evaporative cooling this produced condensates $5\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms, tenfold improvement over previous results. We measured the condensate fraction and repulsive mean-field energy, finding agreement theoretical predictions.

Stimulated small-angle light scattering was used to measure the structure factor of a Bose-Einstein condensate in phonon regime. The excitation strength for phonons found be significantly reduced from that free particles, revealing presence correlated pair excitations and quantum depletion condensate. Bragg resonance line shift agreed with predictions homogeneous Bose gas using local density approximation.

Geometrically frustrated systems with a large degeneracy of low energy states are central interest in condensed-matter physics. The kagome net - pattern corner-sharing triangular plaquettes presents particularly high degree frustration, reflected the non-dispersive orbital bands. ground state quantum antiferromagnet, proposed to be spin liquid or valence bond solid, remains uncertain despite decades work. Solid-state magnets suffer from significant magnetic disorder anisotropy that...

Sound propagation has been studied in a magnetically trapped dilute Bose-Einstein condensate. Localized excitations were induced by suddenly modifying the trapping potential using optical dipole force of focused laser beam. The resulting sound was observed novel technique, rapid sequencing nondestructive phase-contrast images. speed determined as function density and found to be consistent with Bogoliubov theory. This method may generally used observe high-lying modes perhaps second sound.

The properties of Bose-Einstein condensed gases can be strongly altered by tuning the external magnetic field near a Feshbach resonance. resonances affect elastic collisions and lead to observed modification scattering length. However, as we report here, rate inelastic was enhanced in sodium condensate when length tuned both larger or smaller values than off-resonant value. These strong losses impose severe limitations for using tune condensates.

Bose-Einstein condensates have been prepared in long-lived metastable excited states. Two complementary types of states were observed. The first is due to the immiscibility multiple components condensate, and second local suppression spin-relaxation collisions. Relaxation via recondensation noncondensed atoms, spin relaxation, quantum tunneling was These experiments done with $F\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ spinor sodium confined an optical dipole trap.

The spatial observation of a Bose condensate is reported. Dispersive light scattering was used to observe the separation between condensed and normal components gas inside magnetic trap. This technique nondestructive, about hundred images same can be taken. width angular distribution scattered increased suddenly at phase transition.

Collective excitations of a dilute Bose gas were probed above and below the Bose-Einstein condensation temperature. The temperature dependencies frequency damping rates condensate oscillations indicate significant interactions between thermal cloud. Hydrodynamic cloud analogous to first sound observed. An out-of-phase dipolar oscillation was also studied, second sound. observed in situ using nondestructive imaging techniques.

Single cesium atoms are cooled and trapped inside a small optical cavity by way of novel far-off-resonance dipole-force trap, with observed lifetimes 2-3 s. Trapped continuously via transmission strongly coupled probe beam, individual events lasting approximately 1 The loss successive from the trap N>/=3-->2-->1-->0 is thereby monitored in real time. Trapping, cooling, interactions strong coupling enabled potential, for which center-of-mass motion only weakly dependent on atom's internal state.

We have produced Bose-Einstein condensates in a ring-shaped magnetic waveguide. The few-millimeter diameter, nonzero-bias ring is formed from time-averaged quadrupole ring. Condensates that propagate around the make several revolutions within time it takes for them to expand fill shape ideally suited studies of vorticity multiply connected geometry and promising as rotation sensor.