Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Double well potential"”.
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Bose-Einstein Condensates in a Single Double Well Potential
… 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 dynamical variables, the population …
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Experiments with Bose-Einstein condensates in a double-well potential
… 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 shown to be reproducible. Microfabricated …
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Monotonicity of the Period Function for Hamiltonian Systems with Potentials
… the period function for Hamiltonian systems with potentials, we denote as oscillators. Departing from traditional methods, we partition each orbit into two segments and analyse the period restricted to these segments. Analogously to the period function, these restrictions can be extended as …
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On the Stability of Solutions to a Phase Transition Model
… where <italic> F(u) </italic> is a so-called "double-well'' potential. We consider both classical and nonclassical examples for F. Furthermore, the main method we use in this discussion of stability is that of upper and lower solutions.
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Nonlinear dynamics of a matter-wave soliton in driven potentials
… confined by a one dimensional harmonic or double-well trapping potential, and subject to weak periodic driving. Such systems have potential applications in metrology, specifically in the use of atom interferometers for high precision inertial and gravitational field sensing. The localised …
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Nonlinear dynamics of a matter-wave soliton in driven potentials
… confined by a one dimensional harmonic or double-well trapping potential, and subject to weak periodic driving. Such systems have potential applications in metrology, specifically in the use of atom interferometers for high precision inertial and gravitational field sensing. The localised …
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Stochastic chaos and thermodynamic phase transitions : theory and Bayesian estimation algorithms
… consider the motion of a particle trapped in a double-well potential coupled to a noisy environment. By use of the classic Langevin and Fokker-Planck equations, we investigate Kramers' escape rate problem. We show that there is a deep analogy between kinetic rate theory and stochastic chaos, for …
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A free boundary problem inspired by a conjecture of De Giorgi
… + W(u), where W(u) = (1 - u2 )2/2 is a standard double-well potential. According to a famous conjecture of De Giorgi, global critical points of J that are bounded and monotone in one direction have levell sets that are hyperplanes, at least up to dimension 8. Recently, Del Pino, Kowalczyk and Wei …
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Observation of nonlinear tunneling of a Bose-Einstein condensate in a single Josephson junction
… constitutes the nonlinear generalization of the well known Josephson junction of weakly-coupled superconductors that are separated by a thin insulating barrier. In our experiment, the required overlap of two macroscopic wavefunctions is provided by loading a BEC into an optical double well …
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Coupled mode reductions and rotating wave approximations in nonlinear equations
… Pitaevskii (NLS/GP) equation with a linear double-well potential and study justifications of the rotating wave approximations in lattice systems. First, we study the long-time dynamics near a symmetry breaking bifurcation point of the cubic-quintic NLS/GP with symmetric double-well …
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Microtraps and waveguides for Bose-Einstein condensates
… surface, perturbations to the waveguide potential spatially modulated the condensate density. The condensate lifetime was >[or equal to] 20 s and independent of the atom-surface separation, for separations >[or equal to] 70 [mu]m. Condensates were coherently split by deforming an optical …
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Quantum coherence and magnetism in bosonic and fermionic gases of ultracold atoms
… (BEC) was studied in a radio frequency induced double-well potential implemented on a microfabricated atom chip. We observed phase coherence between the separated condensates for times up to 200 ms after splitting, a factor of 10 longer than the phase diffusion time expected for a coherent state …
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Mean-field theory for the dynamics of superfluid fermions in the BCS-BEC crossover
… and self-trapping of superfluid fermions in a double-well potential with time-dependent Bogoliubov-de Gennes equations. We investigate the behaviour of a two-component Fermi superfluid. We numerically solve the time-dependent Bogoliubov-de Gennes equations and characterize the regimes of …
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Potential Energy Surfaces for Intermolecular Proton Transfers in Crystalline Aspirin: A Computational Study
… density functional theory were used to model the potential energy surface of intermolecular proton transfers in crystalline aspirin. Using these surfaces the importance of intermolecular interactions and excited states to the proton transfer were also explored. In addition, the ability of ab …
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Superconducting Asynchronous Logic for Ultra-low Power High Performance Computing
… the location of a single flux quanta in a double-well potential. The heart of the project lies in the modular architecture design that realigns hardware layout with software dataflow to allow for scalable, distributed computing systems from basic circuit building blocks. Projecting the …
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Quantum Resonant Beats and Revivals in the Morse Oscillators and Rotors
… a simple sum of two Morse oscillators led to a double-Morse well whose geometric symmetry provided analytical eigenfunctions and eigenvalues for certain low-lying energy levels. The quantum tunneling between the double-Morse well significantly affected the resonant beats and revivals local to …
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High contrast interferometry and finite temperature coherence of Bose-Einstein condensates
… of Bose-Einstein condensates is presented as well as introducing the various studies and applications in metrology involving BECs. The theory of the techniques used to create a BEC, such as laser cooling, trapping and evaporation, are discussed along with the dynamics of BECs, matter-wave …
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Design, Fabrication, and Characterization of an Array of Graphene Based Variable Capacitors
… characterized in 2004, graphene has shown the potential for a technological revolution. This is due to its amazing physical properties such as high electrical conductivity, high thermal conductivity, and extreme flexibility. Freestanding graphene membranes naturally possesses an intrinsic …
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A tunable Bose-Einstein condensate for quantum interferometry
… starts with the preparation of a BEC in a double well potential. By the effect of strong interactions the atomic system can be driven into an entangled state. Once the entangled state is prepared, interactions can be †switched off†and the interferometric sequence performed. This …
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Properties of rotating ultracold bosonic quantum gases
… for transitions between these states, as well as the critical frequency for appearance of a metastable state with an off-center vortex and its image vortex in the evanescent tail of the cloud. Then, we show how the configuration-space form of the above-mentioned Bogoliubov ground-state …
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