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David J. Toms - One of the best experts on this subject based on the ideXlab platform.
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Bose-Einstein Condensation under external conditions
Physics Letters A, 1998Co-Authors: Klaus Kirsten, David J. TomsAbstract:We examine the occurrence of Bose-Einstein Condensation in both nonrelativistic and relativistic systems with no self-interactions in a general setting. A simple condition for the occurrence of Bose-Einstein Condensation can be given if we adopt generalized ζ-functions to define the quantum theory. We show that the crucial feature governing Bose-Einstein Condensation is the dimension q associated with the continuous part of the eigenvalue spectrum of the Hamiltonian for nonrelativistic systems or the spatial part of the Klein-Gordon operator for relativistic systems. In either case Bose-Einstein Condensation can only occur if q ≥ 3 [1]. Several examples, some of them not completely solved before, may be treated very easily using our simple criterion [2]. These examples are charged free gases confined in finite volumes as torus, boxes, spheres, cylinders (see also [3, 4, 5, 6]) and in the presence of general constant external magnetic fields ([7, 8, 9, 10]).
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Simple criterion for the occurrence of Bose-Einstein Condensation and the Meissner-Ochsenfeld effect
Physical Review D, 1997Co-Authors: Klaus Kirsten, David J. TomsAbstract:We examine the occurrence of Bose-Einstein Condensation in both nonrelativistic and relativistic systems with no self-interactions in a general setting. A simple condition for the occurrence of Bose-Einstein Condensation is given. We show that Condensation can occur only if q{ge}3, where q is the dimension associated with the continuous part of the eigenvalue spectrum of the Hamiltonian for nonrelativistic systems or the spatial part of the Klein-Gordon operator for relativistic systems. Furthermore we show that the criterion for the appearance of the Meissner-Ochsenfeld effect is closely connected with that for the appearance of Bose-Einstein Condensation. {copyright} {ital 1997} {ital The American Physical Society}
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Simple criterion for the occurrence of Bose-Einstein Condensation
Physics Letters B, 1996Co-Authors: Klaus Kirsten, David J. TomsAbstract:Abstract We examine the occurrence of Bose-Einstein Condensation in both nonrelativistic and relativistic systems with no self-interactions in a general setting. A simple condition for the occurrence of Bose-Einstein Condensation can be given if we adopt generalized ξ-functions to define the quantum theory. We show that the crucial feature governing Bose-Einstein Condensation is the dimension q associated with the continuous part of the eigenvalue spectrum of the Hamiltonian for nonrelativistic systems or the spatial part of the Klein-Gordon operator for relativistic systems. In either case Bose-Einstein Condensation can only occur if q ≥ 3.
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Effective action approach to Bose-Einstein Condensation of ideal gases
Journal of research of the National Institute of Standards and Technology, 1996Co-Authors: Klaus Kirsten, David J. TomsAbstract:We present a short review of how the effective action formalism, well known in relativistic quantum field theory, can be used to discuss Bose-Einstein Condensation of non-relativistic gases. This method lends itself very naturally to an interpretation of Bose-Einstein Condensation in terms of symmetry breaking. It also allows for the definition of a very elegant regularization technique involving generalized z -functions. We show how this method can be used to recover the well known results for the free boson gas, as well as the charged boson gas in a constant magnetic field. A general criterion for interpreting Bose-Einstein Condensation in terms of a phase transition with symmetry breaking is given. Finally we present an analysis of Bose-Einstein Condensation in a harmonic oscillator confining potential trap, and show how the results of this simple model are in excellent agreement with experiment.
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Bose-Einstein Condensation of a charged relativistic ideal gas in a general homogeneous magnetic field.
Physical review. D Particles and fields, 1994Co-Authors: David J. TomsAbstract:It is shown how the effective action formalism and [zeta]-function regularization can be used to study Bose-Einstein Condensation for a relativistic charged scalar field in a general homogeneous magnetic field in a spacetime of arbitrary dimension. In the special case where the magnetic field has only one component, Bose-Einstein Condensation occurs at high temperature only for [ital D][ge]5 where [ital D] is the spatial dimension. When Bose-Einstein Condensation does occur the ground-state expectation value of the scalar field is not constant and we determine its value. If the magnetic field has [ital p] independent nonzero components we show that the condition for Bose-Einstein Condensation is [ital D][ge]3+2[ital p]. In particular, Bose-Einstein Condensation can never occur if the magnetic field has all of its independent components nonzero. The problem of Bose-Einstein Condensation in a cylindrical box in [ital D] spatial dimensions with a uniform magnetic field directed along the axis of the cylinder is also discussed.
Wolfgang Ketterle - One of the best experts on this subject based on the ideXlab platform.
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Observation of Bose-Einstein Condensation of molecules
Conference on Lasers and Electro-Optics International Quantum Electronics Conference and Photonic Applications Systems Technologies, 2004Co-Authors: Martin Zwierlein, Claudiu A. Stan, Christian H. Schunck, S. M. F. Raupach, Wolfgang KetterleAbstract:We have observed Bose-Einstein Condensation of molecules, created from a spin mixture of fermionic 6Li atoms. The condensate realizes the limit of tightly bound fermion pairs in the crossover between BCS and BEC superfluidity
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Observation of Bose-Einstein Condensation of molecules.
Physical review letters, 2003Co-Authors: Martin Zwierlein, Claudiu A. Stan, Christian H. Schunck, S. M. F. Raupach, Subhadeep Gupta, Zoran Hadzibabic, Wolfgang KetterleAbstract:We have observed Bose-Einstein Condensation of molecules. When a spin mixture of fermionic $^{6}\mathrm{L}\mathrm{i}$ atoms was evaporatively cooled in an optical dipole trap near a Feshbach resonance, the atomic gas was converted into $^{6}\mathrm{L}\mathrm{i}_{2}$ molecules. Below 600 nK, a Bose-Einstein condensate of up to 900 000 molecules was identified by the sudden onset of a bimodal density distribution. This condensate realizes the limit of tightly bound fermion pairs in the crossover between BCS superfluidity and Bose-Einstein Condensation.
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Bose-Einstein Condensation of atomic gases.
Nature, 2002Co-Authors: James R. Anglin, Wolfgang KetterleAbstract:The early experiments on Bose-Einstein Condensation in dilute atomic gases accomplished three long-standing goals. First, cooling of neutral atoms into their motional ground state, thus subjecting them to ultimate control, limited only by Heisenberg's uncertainty relation. Second, creation of a coherent sample of atoms, in which all occupy the same quantum state, and the realization of atom lasers - devices that output coherent matter waves. And third, creation of a gaseous quantum fluid, with properties that are different from the quantum liquids helium-3 and helium-4. The field of Bose-Einstein Condensation of atomic gases has continued to progress rapidly, driven by the combination of new experimental techniques and theoretical advances. The family of quantum-degenerate gases has grown, and now includes metastable and fermionic atoms. Condensates have become an ultralow-temperature laboratory for atom optics, collisional physics and many-body physics, encompassing phonons, superfluidity, quantized vortices, Josephson junctions and quantum phase transitions.
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Experimental studies of Bose-Einstein Condensation
Physics Today, 1999Co-Authors: Wolfgang KetterleAbstract:The possibility of creating optical fields with many photons in a single mode of a resonator was realized with the creation of the laser in 1960. The possibility of creating a matter‐wave field with many atoms in a single mode of an atom trap—the atomic equivalent of an optical resonator—was realized with the achievement of Bose–Einstein Condensation (BEC) in 1995.
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Experimental studies of Bose-Einstein Condensation
Optics express, 1998Co-Authors: Dallin Durfee, Wolfgang KetterleAbstract:We describe several experimental studies of Bose-Einstein Condensation in a dilute gas of sodium atoms. These include studies of static and dynamic behavior of the condensate, and of its coherence properties.
Mark I. Gorenstein - One of the best experts on this subject based on the ideXlab platform.
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Bose-Einstein Condensation of pions
Proceedings of Critical Point and Onset of Deconfinement - 4th International Workshop — PoS(CPOD07), 2008Co-Authors: Viktor Begun, Mark I. GorensteinAbstract:Particle number fluctuations are studied in the ideal pion gas approaching Bose-Einstein Condensation. Two different cases are considered: Bose Condensation of pions at large charge densities $\rho_Q$ and Bose Condensation at large total densities of pions $\rho_{\pi}$. Calculations are done in grand canonical, canonical and microcanonical ensembles. At high collision energy, in the samples of events with a fixed number of all pions, $N_{\pi}$, one may observe a prominent signal. When $N_{\pi}$ increases the scaled variances for particle number fluctuations of both neutral and charged pions increase dramatically in the vicinity of the Bose-Einstein Condensation line. As an example, the estimates are presented for $p+p$ collisions at the beam energy of 70 GeV.
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Bose-Einstein Condensation of pions in high multiplicity events
Physics Letters B, 2007Co-Authors: Viktor Begun, Mark I. GorensteinAbstract:Abstract We present microcanonical ensemble calculations of particle number fluctuations in the ideal pion gas approaching Bose–Einstein Condensation. At high collision energy, in the samples of events with a fixed number of all pions, N π , one may observe a prominent signal. When N π increases the scaled variances for particle number fluctuations of both neutral and charged pions increase dramatically in the vicinity of the Bose–Einstein Condensation line. As an example, the estimates are presented for p + p collisions at the beam energy of 70 GeV.
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Bose–Einstein Condensation of pions in high multiplicity events
Physics Letters B, 2007Co-Authors: Viktor Begun, Mark I. GorensteinAbstract:We present microcanonical ensemble calculations of particle number fluctuations in the ideal pion gas approaching Bose-Einstein Condensation. In the samples of events with a fixed number of all pions, $N_{\pi}$, one may observe a prominent signal. When $N_{\pi}$ increases the scaled variances for particle number fluctuations of both neutral and charged pions increase dramatically in the vicinity of the Bose-Einstein Condensation line. As an example, the estimates are presented for $p+p$ collisions at the beam energy of 70 GeV.Comment: 4 pages, 2 figure
Bruno Laburthe-tolra - One of the best experts on this subject based on the ideXlab platform.
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Competition between Bose Einstein Condensation and spin dynamics
Physical Review Letters, 2016Co-Authors: B. Naylor, M. Brewczyk, Mariusz Gajda, O. Gorceix, E. Maréchal, L. Vernac, Bruno Laburthe-tolraAbstract:We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein Condensation, by rapidly cooling a chromium multi-component Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein Condensation is reached before the spin-degrees of freedom fully thermalize. The increase in density due to Bose-Einstein Condensation then triggers spin dynamics, hampering the formation of condensates in spin excited states. Small metastable spinor condensates are nevertheless produced, and manifest strong spin fluctuations.
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Competition between Bose-Einstein Condensation and Spin Dynamics
Physical review letters, 2016Co-Authors: B. Naylor, M. Brewczyk, Mariusz Gajda, O. Gorceix, E. Maréchal, L. Vernac, Bruno Laburthe-tolraAbstract:We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein Condensation by rapidly cooling a chromium multicomponent Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein Condensation is reached before the spin degrees of freedom fully thermalize. The increase in density due to Bose-Einstein Condensation then triggers spin dynamics, hampering the formation of condensates in spin-excited states. Small metastable spinor condensates are, nevertheless, produced, and they manifest in strong spin fluctuations.
Klaus Kirsten - One of the best experts on this subject based on the ideXlab platform.
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Bose-Einstein Condensation under external conditions
Physics Letters A, 1998Co-Authors: Klaus Kirsten, David J. TomsAbstract:We examine the occurrence of Bose-Einstein Condensation in both nonrelativistic and relativistic systems with no self-interactions in a general setting. A simple condition for the occurrence of Bose-Einstein Condensation can be given if we adopt generalized ζ-functions to define the quantum theory. We show that the crucial feature governing Bose-Einstein Condensation is the dimension q associated with the continuous part of the eigenvalue spectrum of the Hamiltonian for nonrelativistic systems or the spatial part of the Klein-Gordon operator for relativistic systems. In either case Bose-Einstein Condensation can only occur if q ≥ 3 [1]. Several examples, some of them not completely solved before, may be treated very easily using our simple criterion [2]. These examples are charged free gases confined in finite volumes as torus, boxes, spheres, cylinders (see also [3, 4, 5, 6]) and in the presence of general constant external magnetic fields ([7, 8, 9, 10]).
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Simple criterion for the occurrence of Bose-Einstein Condensation and the Meissner-Ochsenfeld effect
Physical Review D, 1997Co-Authors: Klaus Kirsten, David J. TomsAbstract:We examine the occurrence of Bose-Einstein Condensation in both nonrelativistic and relativistic systems with no self-interactions in a general setting. A simple condition for the occurrence of Bose-Einstein Condensation is given. We show that Condensation can occur only if q{ge}3, where q is the dimension associated with the continuous part of the eigenvalue spectrum of the Hamiltonian for nonrelativistic systems or the spatial part of the Klein-Gordon operator for relativistic systems. Furthermore we show that the criterion for the appearance of the Meissner-Ochsenfeld effect is closely connected with that for the appearance of Bose-Einstein Condensation. {copyright} {ital 1997} {ital The American Physical Society}
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Simple criterion for the occurrence of Bose-Einstein Condensation
Physics Letters B, 1996Co-Authors: Klaus Kirsten, David J. TomsAbstract:Abstract We examine the occurrence of Bose-Einstein Condensation in both nonrelativistic and relativistic systems with no self-interactions in a general setting. A simple condition for the occurrence of Bose-Einstein Condensation can be given if we adopt generalized ξ-functions to define the quantum theory. We show that the crucial feature governing Bose-Einstein Condensation is the dimension q associated with the continuous part of the eigenvalue spectrum of the Hamiltonian for nonrelativistic systems or the spatial part of the Klein-Gordon operator for relativistic systems. In either case Bose-Einstein Condensation can only occur if q ≥ 3.
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Effective action approach to Bose-Einstein Condensation of ideal gases
Journal of research of the National Institute of Standards and Technology, 1996Co-Authors: Klaus Kirsten, David J. TomsAbstract:We present a short review of how the effective action formalism, well known in relativistic quantum field theory, can be used to discuss Bose-Einstein Condensation of non-relativistic gases. This method lends itself very naturally to an interpretation of Bose-Einstein Condensation in terms of symmetry breaking. It also allows for the definition of a very elegant regularization technique involving generalized z -functions. We show how this method can be used to recover the well known results for the free boson gas, as well as the charged boson gas in a constant magnetic field. A general criterion for interpreting Bose-Einstein Condensation in terms of a phase transition with symmetry breaking is given. Finally we present an analysis of Bose-Einstein Condensation in a harmonic oscillator confining potential trap, and show how the results of this simple model are in excellent agreement with experiment.