Large spin relaxation rates in trapped submerged-shell atoms

Connolly, Colin B.; Au, Yat Shan; Doret, S. Charles; Ketterle, Wolfgang; Doyle, John M.

doi:10.1103/physreva.81.010702

Cited by 34 publications

(44 citation statements)

References 33 publications

(52 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our measured Zeeman relaxation rate is one to two orders of magnitude larger than these estimated magnetic dipolar relaxation rates, suggesting that dipolar relaxation is not solely responsible for this fast decay. We also find that the rates for Ho and Dy are significantly smaller than rates in similarly trapped Er and Tm, 3.0 × 10 −10 and 1.1 × 10 −10 cm 3 s −1 , respectively [22], which have smaller magnetic dipoles. This observation further suggests that magnetic dipole-dipole interactions are not the dominate mechanism for Zeeman relaxation in collisions between rareearth-metal atoms.…”

Section: Discussionmentioning

confidence: 81%

“…We observe inelastic magnetic moment reorientation rates for both Ho and Dy that are at least an order of magnitude larger than expected due to the magnetic dipole-dipole interaction. Comparison of these rates to other buffer gas cooled atoms [20][21][22] suggest that anisotropic electrostatic interactions dominate the inelastic collision cross section for these open-shell atoms.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic relaxation in dysprosium-dysprosium collisions

Newman

Brahms

et al. 2011

Phys. Rev. A

Self Cite

View full text Add to dashboard Cite

The collisional magnetic reorientation rate constant g R is measured for magnetically trapped atomic dysprosium (Dy), an atom with large magnetic dipole moments. Using buffer gas cooling with cold helium, large numbers (>10 11 ) of Dy are loaded into a magnetic trap and the buffer gas is subsequently removed. The decay of the trapped sample is governed by collisional reorientation of the atomic magnetic moments. We find g R = 1.9 ± 0.5 × 10 −11 cm 3 s −1 at 390 mK. We also measure the magnetic reorientation rate constant of holmium (Ho), another highly magnetic atom, and find g R = 5 ± 2 × 10 −12 cm 3 s −1 at 690 mK. The Zeeman relaxation rates of these atoms are greater than expected for the magnetic dipole-dipole interaction, suggesting that another mechanism, such as an anisotropic electrostatic interaction, is responsible. Comparison with estimated elastic collision rates suggests that Dy is a poor candidate for evaporative cooling in a magnetic trap.

show abstract

Section: Discussionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Magnetic relaxation in dysprosium-dysprosium collisions

Newman

Brahms

et al. 2011

Phys. Rev. A

Self Cite

View full text Add to dashboard Cite

show abstract

“…The moderate magnetic moment of N atoms (3 µ B ) is large enough to enable efficient magnetic trapping and evaporative cooling [17,26] and small enough to make collision-induced dipolar relaxation inefficient. The latter property is particularly important since large inelastic loss rates recently observed in collisions of highly magnetic atoms [74,75] make these atoms unsuitable for sympathetic cooling of molecules in permanent magnetic traps. …”

Section: Discussionmentioning

confidence: 99%

Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules

et al. 2010

View full text Add to dashboard Cite

We report a combined experimental and theoretical study of collision-induced dipolar relaxation in a cold spin-polarized gas of atomic nitrogen (N). We use buffer gas cooling to create trapped samples of 14 N and 15 N atoms with densities (5 ± 2) × 10 12 cm −3 and measure their magnetic relaxation rates at milli-Kelvin temperatures. These measurements, together with rigorous quantum scattering calculations based on accurate ab initio interaction potentials for the 7 + u electronic state of N 2 demonstrate that dipolar relaxation in N + N collisions occurs at a slow rate of ∼10 −13 cm 3 /s over a wide range of temperatures (1 mK to 1 K) and magnetic fields (10 mT to 2 T). The calculated dipolar relaxation rates are insensitive to small variations of the interaction potential and to the magnitude of the spin-exchange interaction, enabling the accurate calibration of the measured N atom density. We find consistency between the calculated and experimentally determined rates. Our results suggest that N atoms are promising candidates for future experiments on sympathetic cooling of molecules.

show abstract

“…The Er electronic configuration is characterized by a xenonlike core, an inner open 4 f shell, and an outer closed 6s shell, [Xe]4f 12 6s 2 . The electron vacancies in the inner f shell are a common feature of all the lanthanides (with the exception of Yb) and are at the origin of the strong magnetism as well as various interesting collisional effects [18][19][20].…”

mentioning

confidence: 99%

Narrow-line magneto-optical trap for erbium

et al. 2012

View full text Add to dashboard Cite

We report on the experimental realization of a robust and efficient magneto-optical trap for erbium atoms, based on a narrow cooling transition at 583 nm. We observe up to N = 2 × 10 8 atoms at a temperature of about T = 15 µK. This simple scheme provides better starting conditions for direct loading of dipole traps as compared to approaches based on the strong cooling transition alone, or on a combination of a strong and a narrow kHz transition. Our results on Er point to a general, simple and efficient approach to laser cool samples of other lanthanide atoms (Ho, Dy, and Tm) for the production of quantum-degenerate samples.PACS numbers: 37.10. De, 37.10.Vz Laser cooling of non-alkali atoms has become a very active and challenging field of research. The great appeal of unconventional atomic systems for experiments on ultracold atomic quantum gases stems from the possibility of engineering complex interactions and of accessing rich atomic energy spectra. Both features are at the foundation of a number of novel fascinating phenomena. For instance the energy spectra of two-valence-electron species, as alkaline earth and alkalineearth-like atoms, feature narrow and ultra-narrow optical transitions, which are key ingredients for ultra-precise atomic clocks [1], efficient quantum computation schemes [2], and novel laser cooling approaches as beautifully demonstrated in experiments with Sr, Yb,.As a next step in complexity, multi-valence-electron atoms with non-S electronic ground state such as lanthanides are currently attracting an increasing experimental and theoretical interest. Among many, one of the special features of lanthanides is the exceptionally large magnetic dipole moment of atoms in the electronic ground state (e. g. 7 µ B for Er and 10 µ B for both Dy and Tb), which provides a unique chance to study strongly dipolar phenomena with atoms. Highly magnetic atoms interact with each other not only via the usual contact interaction but also via an anisotropic and long-range interaction, known as the dipole-dipole interaction [6]. Chromium was the first atomic species used for experiments on atomic dipolar quantum gases [7,8], and the even more magnetic lanthanides are nowadays in the limelight thanks to laser cooling experiments on Er and Tm [9,10] and to the recent realization of quantumdegenerate Dy gases [11,12].Similarly to Yb and the alkaline earth atoms, the atomic energy spectra of magnetic lanthanides include broad, narrow, and ultra-narrow optical transitions. This collection of lines is reflected in a wide choice of possible schemes for laser cooling experiments. However, all experiments on Zeeman slowing and cooling in a magneto-optical trap (MOT) with magnetic lanthanides so far relied on an approach, essentially based on the strongest cycling transition [9,10,13]. This broad transition typically lies in the blue between 400 and 430 nm and has a linewidth on the order of few tens of MHz. As a consequence, the Doppler temperature is close to a mK. Such a high temperature makes direct loading f...

show abstract

Large spin relaxation rates in trapped submerged-shell atoms

Cited by 34 publications

References 33 publications

Magnetic relaxation in dysprosium-dysprosium collisions

Magnetic relaxation in dysprosium-dysprosium collisions

Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules

Narrow-line magneto-optical trap for erbium

Contact Info

Product

Resources

About