875 research outputs found

    Theory for p-Wave Feshbach Molecules

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    We determine the physical properties of \emph{p}-wave Feshbach molecules in doubly spin-polarized 40^{40}K and find excellent agreement with recent experiments. We show that these molecules have a large probability ZZ to be in the closed channel or bare molecular state responsible for the Feshbach resonance. In the superfluid state this allows for observation of Rabi oscillations between the molecular and atomic components of the Bose-Einstein condensed pairs, which contains a characteristic signature of the quantum phase transition that occurs as a function of applied magnetic field.Comment: Replaced with published versio

    Renormalization Group Theory for the Imbalanced Fermi Gas

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    We formulate a wilsonian renormalization group theory for the imbalanced Fermi gas. The theory is able to recover quantitatively well-established results in both the weak-coupling and the strong-coupling (unitarity) limit. We determine for the latter case the line of second-order phase transitions of the imbalanced Fermi gas and in particular the location of the tricritical point. We obtain good agreement with the recent experiments of Y. Shin {\it et al}. [Nature {\bf 451}, 689 (2008)].Comment: Replaced with published versio

    Resonances in rotationally inelastic scattering of OH(X2ΠX^2\Pi) with helium and neon

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    We present detailed calculations on resonances in rotationally and spin-orbit inelastic scattering of OH (X\,^2\Pi, j=3/2, F_1, f) radicals with He and Ne atoms. We calculate new \emph{ab initio} potential energy surfaces for OH-He, and the cross sections derived from these surfaces compare favorably with the recent crossed beam scattering experiment of Kirste \emph{et al.} [Phys. Rev. A \textbf{82}, 042717 (2010)]. We identify both shape and Feshbach resonances in the integral and differential state-to-state scattering cross sections, and we discuss the prospects for experimentally observing scattering resonances using Stark decelerated beams of OH radicals.Comment: 14 pages, 15 Figure

    Scattering resonances in slow NH3{}_3-He collisions

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    We theoretically study slow collisions of NH3_3 molecules with He atoms, where we focus in particular on the observation of scattering resonances. We calculate state-to-state integral and differential cross sections for collision energies ranging from 104{}^{-4} cm1^{-1} to 130 cm1^{-1}, using fully converged quantum close-coupling calculations. To describe the interaction between the NH3{}_3 molecules and the He atoms, we present a four-dimensional potential energy surface, based on an accurate fit of 4180 {\it ab initio} points. Prior to collision, we consider the ammonia molecules to be in their antisymmetric umbrella state with angular momentum j=1j=1 and projection k=1k=1, which is a suitable state for Stark deceleration. We find pronounced shape and Feshbach resonances, especially for inelastic collisions into the symmetric umbrella state with j=k=1j=k=1. We analyze the observed resonant structures in detail by looking at scattering wavefunctions, phase shifts, and lifetimes. Finally, we discuss the prospects for observing the predicted scattering resonances in future crossed molecular beam experiments with a Stark-decelerated NH3_3 beam.Comment: 17 pages, 12 figure

    Ground states and dynamics of population-imbalanced Fermi condensates in one dimension

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    By using the numerically exact density-matrix renormalization group (DMRG) approach, we investigate the ground states of harmonically trapped one-dimensional (1D) fermions with population imbalance and find that the Larkin-Ovchinnikov (LO) state, which is a condensed state of fermion pairs with nonzero center-of-mass momentum, is realized for a wide range of parameters. The phase diagram comprising the two phases of i) an LO state at the trap center and a balanced condensate at the periphery and ii) an LO state at the trap center and a pure majority component at the periphery, is obtained. The reduced two-body density matrix indicates that most of the minority atoms contribute to the LO-type quasi-condensate. With the time-dependent DMRG, we also investigate the real-time dynamics of a system of 1D fermions in response to a spin-flip excitation.Comment: 20 pages, 15 figures, accepted for publication in New Journal of Physic
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