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| 2. |
- Pavlovic, Z, et al.
(författare)
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Collisional properties of trapped cold chromium atoms
- 2004
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 69:3, s. 1-030701
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Tidskriftsartikel (refereegranskat)abstract
- We report on calculations of the elastic cross section and thermalization rate for collision between two maximally spin-polarized chromium atoms in the cold and ultracold regimes, relevant to buffer-gas and magneto-optical cooling. We calculate ab initio potential-energy curves for Cr-2 and the van der Waals coefficient C-6, and construct interaction potentials between two colliding Cr atoms. We explore the effect of shape resonances on the elastic cross section, and find that they dramatically affect the thermalization rate. Our calculated value for the s-wave scattering length is compared in magnitude with a recent measurement. We propose that a dip in the elastic rate coefficient could be experimentally exploited to obtain an accurate value for the scattering length.
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| 3. |
- Pavlovic, Z., et al.
(författare)
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CrRb: A molecule with large magnetic and electric dipole moments
- 2010
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 81:5
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Tidskriftsartikel (refereegranskat)abstract
- We report calculations of Born-Oppenheimer potential energy curves of the chromium-rubidium heteronuclear molecule ((CrRb)-Cr-52-Rb-87), and the long-range dispersion coefficient for the interaction between ground state Cr and Rb atoms. Our calculated van der Waals coefficient (C-6 = 1770 a.u.) has an expected error of 3%. The ground state (6)Sigma(+) molecule at its equilibrium separation has a permanent electric dipole moment of d(e)(R-e = 3.34 angstrom) = 2.90 D. We investigate the hyperfine and dipolar collisions between trapped Cr and Rb atoms, finding elastic to inelastic cross section ratio of 10(2)-10(3).
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| 4. |
- Halder, S., et al.
(författare)
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Control of Dy 164 Bose-Einstein condensate phases and dynamics with dipolar anisotropy
- 2022
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Ingår i: Physical Review Research. - 2643-1564. ; 4:4
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the quench dynamics of quasi-one- and two-dimensional dipolar Bose-Einstein condensates of Dy164 atoms under the influence of a fast rotating magnetic field. The magnetic field thus controls both the magnitude and sign of the dipolar potential. We account for quantum fluctuations, critical to formation of exotic quantum droplet and supersolid phases in the extended Gross-Pitaevskii formalism, which includes the so-called Lee-Huang-Yang correction. An analytical variational ansatz allows us to obtain the phase diagrams of the superfluid and droplet phases. The crossover from the superfluid to the supersolid phase and to single and droplet arrays is probed with particle number and dipolar interaction. The dipolar strength is tuned by rotating the magnetic field with subsequent effects on phase boundaries. Following interaction quenches across the aforementioned phases, we monitor the dynamical formation of supersolid clusters or droplet lattices. We include losses due to three-body recombination over the crossover regime, where the three-body recombination rate coefficient scales with the fourth power of the scattering length (as) or the dipole length (add). For fixed values of the dimensionless parameter, ϵdd=add/as, tuning the dipolar anisotropy leads to an enhancement of the droplet lifetimes.
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| 5. |
- Huh, Seung Jung, et al.
(författare)
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Universality class of a spinor Bose–Einstein condensate far from equilibrium
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Ingår i: Nature Physics. - 1745-2473.
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Tidskriftsartikel (refereegranskat)abstract
- Scale invariance and self-similarity in physics provide a unified framework for classifying phases of matter and dynamical properties near equilibrium in both classical and quantum systems. This paradigm has been further extended to isolated many-body quantum systems driven far from equilibrium, for which the physical observables exhibit dynamical scaling with universal scaling exponents. Universal dynamics appear in a wide range of scenarios, including cosmology, quark–gluon matter, ultracold atoms and quantum spin magnets. However, how the universal dynamics depend on the symmetry of the underlying Hamiltonian in non-equilibrium systems remains an outstanding challenge. Here we report on the classification of universal coarsening dynamics in a quenched two-dimensional ferromagnetic spinor Bose gas. We observe spatio-temporal scaling of spin correlation functions with distinguishable scaling exponents that characterize binary and diffusive fluids. The universality class of the coarsening dynamics is determined by the symmetry of the order parameter and the dynamics of the topological defects, such as domain walls and vortices. Our results categorize the universality classes of far-from-equilibrium quantum dynamics based on the symmetry properties of the system.
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