Giant Spin Relaxation of an Ultracold Cesium Gas

Söding, Johannes; Guéry-Odelin, David; Desbiolles, Pierre; Ferrari, G.; Dalibard, Jean

doi:10.1103/physrevlett.80.1869

Cited by 105 publications

(102 citation statements)

References 16 publications

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“…Large inelastic losses that grow as the temperature is reduced were discovered that prevent the condensation of cesium in this state [25][26][27].…”

Section: Inelastic Feshbach Spectroscopymentioning

confidence: 99%

Precision Feshbach spectroscopy of ultracoldCs2

et al. 2004

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We have observed and located more than 60 magnetic field-induced Feshbach resonances in ultracold collisions of ground-state 133 Cs atoms. Multiple extremely weak Feshbach resonances associated with g-wave molecular states are detected through variations in the radiative collision cross sections. The Feshbach spectroscopy allows us to determine the interactions between ultracold cesium atoms and the molecular energy structure near the dissociation continuum with unprecedented precision. Our work not only represents a very successful collaboration of experimental and theoretical efforts, but also provides essential information for cesium Bose-Einstein condensation, Cs 2 molecules, and atomic clock experiments.

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“…Large inelastic losses that grow as the temperature is reduced were discovered that prevent the condensation of cesium in this state [25][26][27].…”

Section: Inelastic Feshbach Spectroscopymentioning

confidence: 99%

Precision Feshbach spectroscopy of ultracoldCs2

et al. 2004

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“…For all isotope combinations, we find that heteronuclear thermal relaxation is outbalanced by intrinsic heating caused by ionizing collisions: Since ionizing collisions occur preferentially at the center of the trap, where the density is highest and the energy of the atoms is lowest, these collisions remove atoms with below average energy. This leads to an effective heating of the remaining atoms (see also [21,26]). The heating rate per ionizing collision depends on the mean energy E C carried away by the collision products relative to the mean energy E T of all atoms in the trap.…”

Section: Heteronuclear Elastic Collisionsmentioning

confidence: 99%

“…The heating rate per ionizing collision depends on the mean energy E C carried away by the collision products relative to the mean energy E T of all atoms in the trap. The heating rate is given by [26] …”

Section: Heteronuclear Elastic Collisionsmentioning

confidence: 99%

Heteronuclear collisions between laser-cooled metastable neon atoms

et al. 2012

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We investigate heteronuclear collisions in isotope mixtures of laser-cooled metastable ( 3 P2) neon. Experiments are performed with spin-polarized atoms in a magnetic trap for all two-isotope combinations of the stable neon isotopes 20 Ne, 21 Ne, and 22 Ne. We determine the rate coefficients for heteronuclear ionizing collisions to β21,20 = (3.9 ± 2.7) × 10 −11 cm 3 /s, β22,20 = (2.6 ± 0.7) × 10 −11 cm 3 /s, and β21,22 = (3.9 ± 1.9) × 10 −11 cm 3 /s. We also study heteronuclear elastic collision processes and give upper bounds for heteronuclear thermal relaxation cross sections. This work significantly extends the limited available experimental data on heteronuclear ionizing collisions for laser-cooled atoms involving one or more rare gas atoms in a metastable state. I. INTRODUCTIONDue to their high internal energy which surpasses the ionization energy of almost all neutral atomic and molecular collision partners, metastable rare-gas atoms (Rg*) prepared by laser cooling techniques [1] present a unique class of atoms for the investigation of cold and ultracold collisions [2]. With lifetimes ranging from 14.73 s (neon)[3] to 7870 s (helium) [4], the first excited metastable states present effective ground states for applying standard laser cooling techniques. The resulting extremely low kinetic energy of the laser-cooled atoms (≈ 10 −10 eV) stands in strong contrast to the high internal energy between 8 eV (xenon) and 20 eV (helium). This offers unique conditions not accessible with samples of lasercooled alkali-metal atoms. In particular, the high internal energy of the metastable state allows for Penning (PI) and associative (AI) ionizing collisions,to dominate losses in trapped Rg* samples at high densities. Since direct detection of the collision products (using electron multipliers) as well as of the remaining Rg* atoms is possible with high efficiency, detailed studies of homonuclear ionizing collisions have been carried out for all rare gas elements (see [1] for an overview). Additional motivation for these investigations arises from the fact, that favorable rate coefficients for inelastic but also for elastic collisions are essential for the achievement of quantum degeneracy which for Rg* atoms so far has only been demonstrated for 4 He [5-8] and 3 He [9]. For unpolarized Rg* samples, two-body loss rate coefficients for PI [10] between β = 6 × 10 −11 cm 3 /s for 132 Xe [11] and β = 1 × 10 −9 cm 3 /s for 22 Ne [12] have been measured. Spin polarizing the atoms to a spin-stretched * gerhard.birkl@physik.tu-darmstadt.de state may suppress PI: In a collision of atoms in spinstretched states the total spin of the reactants is larger than the total spin of the products. Thus, if spin is conserved, PI collisions should be significantly reduced. In the case of He* in the 3 S 1 state, a suppression of four orders of magnitude has been observed [7,13]. For the heavier rare gases, however, the metastable state 3 P 2 is formed by an exited s electron and a p 5 core with orbital momentum l = 1. This leads to an anisot...

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“…Moreover, investigations in both ultracold gases [24] and optically pumped vapor cells [25] have revealed that even for heavy alkali-metal collisions the hierarchy γ c ≈ γ SE ≫ γ SR is fulfilled. In such a situation, the dominant spin-exchange interaction leads to a steady state near a perfect polarization of spin and environment both when the environment is initially polarized but the spin is unpolarized and when the single spin is continuously pumped but the environment is initially unpolarized.…”

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confidence: 99%

Decoherence of a Single-Ion Qubit Immersed in a Spin-Polarized Atomic Bath

et al. 2013

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We report on the immersion of a spin-qubit encoded in a single trapped ion into a spin-polarized neutral atom environment, which possesses both continuous (motional) and discrete (spin) degrees of freedom. The environment offers the possibility of a precise microscopic description, which allows us to understand dynamics and decoherence from first principles. We observe the spin dynamics of the qubit and measure the decoherence times (T1 and T2), which are determined by the spin-exchange interaction as well as by an unexpectedly strong spin-nonconserving coupling mechanism.PACS numbers: 03.67.-a 03.65.Yz 37.10.Ty A spin-1/2 system represents the most fundamental quantum mechanical object. Its spin-dynamics anddecoherence when interacting with an environment determine its potential use as a qubit and are responsible for a multitude of impurity effects encountered in the solid state. While an extensive amount of theoretical work on this problem exists (for reviews see [1, 2]), experiments with well-controlled and adjustable environments are scarce. The necessary sensitivity to probe single spins, ideally with a single-shot readout, is often incompatible with the ability to adjust the properties of the environment. Among the few examples of controlled decoherence processes are the quantum measurement process [3], the decoherence of motional quantum states of trapped ions by noisy classical electric fields [4], and the effects of spontaneous emission [5][6][7]. These are related to spin-boson physics, where the environment is formed by a set of harmonic oscillator modes [1]. On the contrary, the decoherence of a localized spin impurity inside an environment of other spins lies at the heart of the so-called central-spin problem [2]. Here, the occurring decoherence mechanisms are different from spinboson physics since the spectrum of the bath is discrete and spin-spin or spin-orbit interactions play a role. The central-spin model has been often applied as a simplified and approximate description of the interaction of semiconductor quantum dots [8] and color centres in solids [9] with their environment.Here we investigate the model system of a single localized spin-1/2 coupled to an spin-polarized environment of tunable density. Specifically, we embed a trapped single Yb + ion, initially laser-cooled to Doppler temperature, into a spin-polarized ultracold neutral bath of 87 Rb atoms and study the resulting decoherence of the ion's internal spin state. We observe an intricate decoherence mechanism, which is spin-nonconserving and involves the coupling of the orbital degrees of freedom with the spin degrees of freedom. We measure the longitudinal (T 1 ) and the transverse (T 2 ) coherence times, also with respect to the energy separation, and identify the time scales for Zeeman-and hyperfine-state relaxation. Level structure of the Yb + electronic ground state in a weak magnetic field. To implement the spin-1/2 system, we use either the Zeeman qubit |mJ = ±1/2 in the isotope 174 Yb + or the magnetic field insensitive hype...

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Giant Spin Relaxation of an Ultracold Cesium Gas

Cited by 105 publications

References 16 publications

Precision Feshbach spectroscopy of ultracoldCs2

Precision Feshbach spectroscopy of ultracoldCs2

Heteronuclear collisions between laser-cooled metastable neon atoms

Decoherence of a Single-Ion Qubit Immersed in a Spin-Polarized Atomic Bath

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