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Showing 1 to 20 of 89 for “"Bose-Einstein condensates"”.
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Quantum metrology with Bose-Einstein condensates
… in particular rotation measurements using Bose-Einstein condensates, that are robust to losses. We begin by describing how, by loading a Bose-Einstein condensate into an optical ring lattice, multiport beam splitters are created through a simple raising and lowering of potential barriers …
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Quantum reflection of Bose-Einstein Condensates
Recent developments in atom optics have brought Bose-Einstein condensates within 1 pm of solid surfaces where the atom-surface interactions can no longer be ignored. At long- range, the atom-surface interaction is described by the weakly attractive Casimir-Polder potential which is classically …
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Coherent decay of Bose-Einstein condensates
… coldest form of matter known to exist, atomic Bose-Einstein condensates are unique forms of matter where the constituent atoms lose their individual identities, becoming absorbed into the cloud as a whole. Effectively, these gases become a single macroscopic object that inherits its properties …
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Bogoliubov Excitations of Inhomogeneous Bose-Einstein Condensates
… first part deals with repulsively interacting Bose-Einstein condensates in speckle disorder potentials. In the Bogoliubov approach, the many-body problem is split into the Gross-Pitaevskii condensate (mean-field) and the Bogoliubov excitations, which are bosonic quasiparticles. The disorder …
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⁸⁷Rubidium Bose-Einstein condensates in optical lattices
Bose-Einstein condensates in optical lattices have proven to be a powerful tool for studying a wide variety of physics. In this thesis a series of experiments using optical lattices to manipulate 87Rb Bose-Einstein condensates are described. A systematic shift of the photon recoil momentum due to …
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Manipulating Bose-Einstein condensates with laser light
A dilute gas Bose-Einstein condensate was probed and manipulated by off-resonant laser beams. Spontaneous and stimulated off-resonant light scatterings were studied experimentally. Stimulated, two-photon Bragg scattering was used for spectroscopic measurement of the mean-field energy and of the …
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Dynamic properties of dilute Bose-Einstein condensates
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1999.
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Microtraps and waveguides for Bose-Einstein condensates
Gaseous Bose-Einstein condensates containing up to 3 x 10⁶ ²³Na atoms were loaded into magnetic microtraps and waveguides on a microfabricated "atom chip" using optical tweezers. Single-mode propagation was observed along the waveguide. Closer to the microfabricated surface, perturbations to the …
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Effects of interaction in Bose-Einstein condensates
… s-wave scattering - in the various properties of Bose-Einstein condensates (BEC). The phonon wavefunction in a BEC was measured using Bragg spectroscopy and compared with the well-known Bogoliubov theory. Phonons were first excited in a BEC of 3 x 107 condensed 23Na atoms via small-angle …
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Dynamics of impurities and trapped Bose-Einstein Condensates
… that exists in experiments with cold atoms, and Bose-Einstein condensates, in particular, allows us to design systems with chosen geometries. These provide us with simple model systems that are well understood from first principles microscopically, and with parameters controlled by external …
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Localisation of Bose-Einstein condensates in optical lattices
The properties of Bose-Einstein condensates can be studied and controlled effectively when trapped in optical lattices formed by two counter-propagating laser beams. The dynamics of Bose-Einstein condensates in optical lattices are well-described by a continuous model using the Gross-Pitaevskii …
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Bose-Einstein condensates in magnetic double well potentials
… of magnetic double well potentials for Bose-Einstein condensates (BECs) on atom chips. One approach utilizes static magnetic traps, created by current carrying micro wires, manipulating the atoms close to the chip surface. As in all other atom chip experiments, cold atom clouds are found …
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One-dimensional Bose-Einstein condensates in micro-traps
… generated by wires mounted on the atom chip and Bose-Einstein condensation has been achieved. The Bose-Einstein condensates (BECs) created in the micro-traps form in the one-dimensional Thomas-Fermi regime. The cross-over between three-dimensional and one-dimensional BECs has been investigated by …
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Novel trapping techniques for shaping Bose-Einstein condensates
A combination of radio frequency radiation and magnetic field gradients was used to trap atoms in dressed states. In a magnetic field with a quadrupole minimum. RF fields resonant with the (I F. m)) 11. -1) -- 1, 0) transition trapped the atoms on the surface of a sphere, and gravity caused the …
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Bose-Einstein Condensates in a Single Double Well Potential
… new kind of Josephson junction a 87-Rubidium Bose-Einstein condensate is split in a double well potential into two matter wave packets, which are coupled coherently to each other via quantum mechanical tunneling of atoms through the barrier. The state of the system can be described by two …
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A new apparatus for experiments with Caesium Bose-Einstein Condensates
… an experimental apparatus capable of generating Bose-Einstein condensates (BECs) of spin-polarised caesium-133 atoms. Caesium condensates offer excellent control over interatomic interactions due to the rich landscape of low-field magnetic Feshbach resonances, which enables the study of quantum …
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Asymmetric Structures in Systems of Non-equilibrium Bose-Einstein Condensates
… and applications of systems of interacting Bose-Einstein condensates. The focus of the work is on non-equilibrium condensates that exist within gain-dissipative systems, such as polaritonic or photonic condensates. We first elucidate the nature of an “asymmetric dyad”. In such a structure, …
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⁸⁷Rubidium Bose-Einstein condensates : machine construction and quantum Zeno experiments
… of a new apparatus for the production of 87Rb Bose-Einstein condensates and a subsequent quantum Zeno effect experiment. An experimental apparatus for producing large Bose-Einstein condensates of 87Rb is described in detail. A high flux thermal atomic beam is decelerated by a Zeeman slower and …
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Bosonic Quantum Hall States from Rapidly Rotating Bose-Einstein Condensates
Rotating Bose-Einstein condensates (BECs) were explored as a platform for studying quantum Hall physics. This work relies on the equivalence between neutral particles under rotation and charged particles in a magnetic field to create rotational analogs of quantum Hall states of bosons. A novel …
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Experiments with Bose-Einstein condensates in a double-well potential
Trapped atom interferometry was demonstrated with Bose-Einstein condensates in an optical double-well trap. Coherent splitting of trapped condensates was performed by deforming an optical single-well potential into a double-well potential, and the relative phase of the two split condensates was …
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