A5060585211- Cold Atom Physics and Bose-Einstein Condensates
- Strong Light-Matter Interactions
- Quantum, superfluid, helium dynamics
- Physics of Superconductivity and Magnetism
- Nonlinear Photonic Systems
- Atomic and Subatomic Physics Research
- Quantum Information and Cryptography
- Quantum Electrodynamics and Casimir Effect
- Optical properties and cooling technologies in crystalline materials
- Spectroscopy and Laser Applications
- Spectroscopy and Quantum Chemical Studies
- Advanced Fiber Laser Technologies
- Advanced Materials Characterization Techniques
- Mechanical and Optical Resonators
- Advanced Frequency and Time Standards
- Quantum optics and atomic interactions
- Quantum and electron transport phenomena
- Solar and Space Plasma Dynamics
- Quantum Mechanics and Applications
- Nonlinear Waves and Solitons
- Numerical methods for differential equations
- Molecular Spectroscopy and Structure
- Pulsars and Gravitational Waves Research
- Nonlinear Dynamics and Pattern Formation
- Advanced Thermodynamics and Statistical Mechanics
Washington State University
2015-2024
National Institute of Standards and Technology
2001-2010
National Institute of Standards
2010
University of Colorado Boulder
2001-2006
Princeton University
2000-2003
Leibniz University Hannover
1999-2002
University of Bonn
1999
We create rapidly rotating Bose-Einstein condensates in the lowest Landau level by spinning up to rotation rates Omega > 99% of centrifugal limit for a harmonically trapped gas, while reducing number atoms. As consequence, chemical potential drops below cyclotron energy 2 variant Planck's over 2pi Omega. While this mean-field quantum-Hall regime we still observe an ordered vortex lattice, its elastic shear strength is strongly reduced, as evidenced observed very low frequency Tkachenko...
The dynamics of two penetrating superfluids exhibit an intriguing variety nonlinear effects. Using distinguishable components a Bose-Einstein condensate, we investigate the counterflow in narrow channel. We present first experimental observation trains dark-bright solitons generated by counterflow. Our observations are theoretically interpreted three-dimensional numerical simulations for coupled Gross-Pitaevskii equations and analysis jump relatively flowing components' densities....
Spin-orbit coupled ultra-cold atoms provide an intriguing new avenue for the study of rich spin dynamics in superfluids. In this Letter, we observe Zitterbewegung, simultaneous velocity (thus position) and oscillations, neutral between two spin-orbit bands a Bose-Einstein condensate (BEC) through sudden quantum quenches Hamiltonian. The observed Zitterbewegung oscillations are perfect on short time scale but gradually damp out long scale, followed by strong heating BEC. As application, also...
We experimentally realize the Peregrine soliton in a highly particle-imbalanced two-component repulsive Bose-Einstein condensate immiscible regime. The effective focusing dynamics and resulting modulational instability of minority component provide opportunity to dynamically create with aid an attractive potential well that seeds initial dynamics. formation is reproducible, our experiments allow us separately monitor majority components, compare single absence or presence varying depths....
We have developed an evaporative cooling technique that accelerates the rotation of ultracold $^{87}R\mathrm{b}$ gas, confined in a static harmonic potential. As normal gas is evaporatively spun up and cooled below quantum degeneracy, it found to nucleate vorticity Bose-Einstein condensate. Measurements condensate's aspect ratio surface-wave excitations are consistent with effective rigid-body rotation. Rotation rates $94%$ centrifugal limit inferred. A threshold cloud's observed for...
A Bose-Einstein condensate (BEC) is a quantum fluid that gives rise to interesting shock-wave nonlinear dynamics. Experiments depict BEC exhibits behavior similar of shock wave in compressible gas, e.g., traveling fronts with steep gradients. However, the governing Gross-Pitaevskii (GP) equation describes mean field admits no dissipation, hence classical dissipative solutions do not explain phenomena. Instead, dynamics small dispersion considered and it shown this provides mechanism for...
We observe interlaced square vortex lattices in rotating two-component dilute-gas Bose-Einstein condensates (BEC). After preparing a hexagonal lattice single-component BEC an internal state $|1>$ of $^{87}$Rb atoms, we coherently transfer fraction the superfluid to different $|2>$. The subsequent evolution this pseudo-spin-1/2 towards offset involves intriguing interplay phase-separation and -mixing dynamics, both macroscopically on length scale cores, stage turbulence. Stability structure...
We experimentally study the fluid flow induced by a broad, penetrable barrier moving through an elongated dilute gaseous Bose-Einstein condensate. The is created laser beam swept condensate, and resulting dipole potential can be either attractive or repulsive. examine both cases find regimes of stable unstable flow: At slow speeds barrier, steady due to superfluidity intermediate speeds, we observe unsteady regime in which condensate gets filled with dark solitons. faster soliton formation...
We directly image Tkachenko waves in a vortex lattice dilute-gas Bose-Einstein condensate. The low (sub-Hz) resonant frequencies are consequence of the small but nonvanishing elastic shear modulus vortex-filled superfluid. measured for rotation rates as high 98% centrifugal limit harmonically confined gas. Agreement with hydrodynamic theory worsens increasing rate, perhaps due to fraction volume displaced by cores. also observe two low-lying m=0 longitudinal modes at about 20 times higher frequency.
Faraday waves in a cigar-shaped Bose-Einstein condensate are created. It is shown that periodically modulating the transverse confinement, and thus nonlinear interactions BEC, excites small amplitude longitudinal oscillations through parametric resonance. also demonstrated even without presence of continuous drive, an initial breathing mode excitation leads to spontaneous pattern formation direction. Finally, effects strongly driving with large investigated. In this case, impact-oscillator...
We study the formation of large vortex aggregates in a rapidly rotating dilute-gas Bose-Einstein condensate. When we remove atoms from condensate with tightly focused, resonant laser, density can be locally suppressed, while fast circulation ring-shaped superflow around area suppressed is maintained. Thus giant core comprising 7 to 60 phase singularities formed. The only metastable, and it will refill distinguishable single vortices after many rotation cycles. surprisingly long lifetime...
We investigate the dynamics of two miscible superfluids experiencing fast counterflow in a narrow channel. The are formed by distinguishable components trapped dilute-gas Bose-Einstein condensate (BEC). onset counterflow-induced modulational instability throughout cloud is observed and shown to lead proliferation dark-dark vector solitons. These solitons, which we observe for first time BEC, do not exist single-component systems, exhibit intriguing beating can experience transverse leading...
We investigate a spin-orbit-coupled Bose-Einstein condensate loaded into translating optical lattice. experimentally demonstrate the lack of Galilean invariance in system, which leads to anisotropic behavior depending on direction translation The anisotropy is theoretically understood by an effective dispersion relation. confirm this theoretical picture probing dynamical instability system.
The processes of merging and splitting dilute-gas Bose-Einstein condensates are studied in the nonadiabatic, high-density regime. Rich dynamics found. Depending on experimental parameters, uniform soliton trains containing more than ten solitons or formation a bulge as well dispersive shock waves observed experimentally within merged BECs. Our numerical simulations indicate many vortex rings. In case BEC, transition from sound-wave to shock-wave is by use increasingly stronger barriers....
A negative effective mass can be realized in quantum systems by engineering the dispersion relation. powerful method is provided spin-orbit coupling, which currently at center of intense research efforts. Here we measure an expanding coupled Bose-Einstein condensate whose features a region mass. We observe range dynamical phenomena, including breaking parity and Galilean covariance, instabilities, self-trapping. The experimental findings are reproduced single-band Gross-Pitaevskii...
The experimental and theoretical research of spin–orbit-coupled ultracold atomic gases has advanced expanded rapidly in recent years. Here, we review some the progress that either was pioneered by our own work, helped to lay foundation, or developed new relevant techniques. After examining accessibility all spin–orbit coupling parameters, discuss fundamental properties general applications Bose–Einstein condensates (BECs) over a wide range physical situations. For harmonically trapped case,...
Motivated by recent experimental results, we study beating dark–dark (DD) solitons as a prototypical coherent structure that emerges in two-component Bose–Einstein condensates. We showcase their connection to dark–bright via SO(2) rotation, and infer from it both intrinsic frequency of oscillation inside parabolic trap. identify them exact periodic orbits the Manakov limit equal inter- intra-species nonlinearity strengths with without trap persistence such states upon weak deviations this...
Dilute-gas Bose-Einstein condensates are an exceptionally versatile test bed for the investigation of novel solitonic structures. While matter-wave solitons in one- and two-component systems have been focus intense research efforts, extension to three components has never attempted experiments. Here, we experimentally demonstrate existence robust dark-bright-bright (DBB) dark-dark-bright a multicomponent F=1 condensate. We observe lifetimes on order hundreds milliseconds these Our...
We have studied the dynamics of large vortex lattices in a dilute-gas Bose-Einstein condensate. While undisturbed regular hexagonal structure, large-amplitude quadrupolar shape oscillations condensate are shown to induce wealth nonequilibrium lattice dynamics. When exciting an m = -2 mode, we observe shifting planes, changes and sheet-like structures which individual vortices appear merged. Excitation +2 mode dissolves lattice, leading randomly arranged but still strictly parallel lines.
We present experimental results and a systematic theoretical analysis of dark-br ight soliton interactions multiple-dark-bright complexes in atomic t wo-component Bose-Einstein condensates. study analytically the b etween two-dark-bright solitons homogeneous condensate and, then, extend ou r considerations to presence trap. An effective equation motion is derived for dark-bright center existence stability stationary states illustrated (with bright components being either in- or...
We measure the collective excitation spectrum of a spin-orbit coupled Bose-Einstein condensate using Bragg spectroscopy. The coupling is generated by Raman dressing atomic hyperfine states. When detuning reduced, mode softening at finite momentum revealed, which provides insight towards supersolid-like phase transition. find that for parameters our system, this stops gap and symmetric under sign change detuning. Finally, moving barrier swept through BEC, we also show effect on fluid dynamics.
We characterize several equilibrium vortex effects in a rotating Bose-Einstein condensate. Specifically we attempt precision measurements of the vortex-lattice spacing and vortex-core size over range condensate densities rotation rates. These are supplemented by numerical simulations, both experimental data compared to theory. Finally, study effect centrifugal weakening trapping spring constants on critical temperature for quantum degeneracy finite contrast.