9,260 research outputs found
Magnetic Field Dependence and Efimov Resonance Broadening in Ultracold Three-Body Recombination
We derive an analytic formula which describes the final bound state
dependence in ultracold three-body recombination. Using an energy-dependent
loss parameter, the recently observed broad resonance in an ultracold gas of
Li atoms [T. B. Ottenstein {\it et al.}, Phys. Rev. Lett. 101, 203202
(2008)l J. H. Huckans {\it et al.}, Phys. Rev. Lett. 102, 165302 (2009)] is
described quantitatively. We also provide an analytic and approximation for the
three-body recombination rate which encapsulates the underlying physics of the
universal three-body recombination process.Comment: 4 pages, 4 figure
Comparison of Absorption, Fluorescence, and Polarization Spectroscopy of Atomic Rubidium
An ongoing spectroscopic investigation of atomic rubidium utilizes a two-photon, single-laser excitation process. Transitions accessible with our tunable laser include 5P1/2 (F ′ ) ← 5S1/2 (F) and 5P3/2 (F ′ ) ← 5S1/2 (F). The laser is split into a pump and probe beam to allow for Doppler-free measurements of transitions between hyperfine levels. The pump and probe beams are overlapped in a counter-propagating geometry and the laser frequency scans over a transition. Absorption, fluorescence and polarization spectroscopy techniques are applied to this basic experimental setup. The temperature of the vapor cell and the power of the pump and probe beams have been varied to explore line broadening effects and signal-to-noise of each technique. This humble setup will hopefully grow into a more robust experimental arrangement in which double resonance, two-laser excitations are used to explore hyperfine state changing collisions between rubidium atoms and noble gas atoms. Rb-noble gas collisions can transfer population between hyperfine levels, such as 5P3/2 (F ′ = 3) Collision ←− 5P3/2 (F ′ = 2), and the probe beam couples 7S1/2 (F ′′ = 2) ← 5P3/2 (F ′ = 3). Polarization spectroscopy signal depends on the rate of population transfer due to the collision as well as maintaining the orientation created by the pump laser. Fluorescence spectroscopy relies only on transfer of population due to the collision. Comparison of these techniques yields information regarding the change of the magnetic sublevels, mF , during hyperfine state changing collisions
Three-body rf association of Efimov trimers
We present a theoretical analysis of rf association of Efimov trimers in a
2-component Bose gas with short-range interactions. Using the adiabatic
hyperspherical Green's function formalism to solve the quantum 3-body problem,
we obtain universal expressions for 3-body rf association rates as a function
of the s-wave scattering length . We find that the association rates scale
as in the limit of large , and diverge as whenever
an Efimov state crosses the atom-dimer threshold (where stands for the
atom-dimer scattering length). Our calculations show that trimer formation
rates as large as cm/s can be achieved with rf Rabi
frequencies of order 1 MHz, suggesting that direct rf association is a powerful
tool of making and probing few-body quantum states in ultracold atomic gases.Comment: 4 pages, 2 figure
Global Analysis of Data on the Spin-orbit-coupled A1Σ+ and b3Πu States of Cs2
We present experimentally derived potential curves and spin-orbit interaction functions for the strongly perturbed A1+ u and b3u states of the cesium dimer. The results are based on data from several sources. Laser-induced fluorescence Fourier transform spectroscopy (LIF FTS) was used some time ago in the Laboratoire Aim´e Cotton primarily to study the X1+ g state. More recent work at Tsinghua University provides information from moderate resolution spectroscopy on the lowest levels of the b3± 0u states as well as additional high resolution data. From Innsbruck University, we have precision data obtained with cold Cs2 molecules. Recent data from Temple University was obtained using the optical-optical double resonance polarization spectroscopy technique, and finally, a group at the University of Latvia has added additional LIF FTS data. In the Hamiltonian matrix, we have used analytic potentials (the Expanded Morse Oscillator form) with both finite-difference (FD) coupled-channels and discrete variable representation (DVR) calculations of the term values. Fitted diagonal and off-diagonal spin-orbit functions are obtained and compared with ab initio results from Temple and Moscow State universities
Ultracold giant polyatomic Rydberg molecules: coherent control of molecular orientation
We predict the existence of a class of ultracold giant molecules formed from
trapped ultracold Rydberg atoms and polar molecules. The interaction which
leads to the formation of such molecules is the anisotropic charge-dipole
interaction (). We show that prominent candidate molecules such as KRb
and deuterated hydroxyl (OD) should bind to Rydberg rubidium atoms, with
energies GHz at distances m. These
molecules form in double wells, mimicking chiral molecules, with each well
containing a particular dipole orientation. We prepare a set of correlated
dressed electron-dipole eigenstates which are used in a resonant Raman scheme
to coherently control the dipole orientation and to create cat-like entangled
states of the polar molecule.Comment: 4 pages, 4 figure
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