Spin Destruction in Collisions between Cesium Atoms

Bhaskar, N. D.; Pietras, J.; Camparo, J. C.; Happer, W.; Liran, J.

doi:10.1103/physrevlett.44.930

Cited by 53 publications

(25 citation statements)

References 21 publications

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“…39 However, in the work described here the total gas pressure is on the order of several atmospheres and binary collisions dominate the spin exchange because frequent collisions with the buffer gas severely limit the lifetime (and hence the Rb-Xe spin-exchange contact time) of the van der Waals complexes [452,454,455]. 40 The duration of a binary collision is very short (on alkali-alkali atom collisions that do not conserve total spin angular momentum [445,446,447], [32, §5.8]. 39 Heavy noble gases (such as Xe) form these complexes more easily than light ones because they experience longer-range van der Waals forces due to their larger electronic polarizabilities.…”

Section: Heteronuclear Ddf Indirect Detection Experiments Using Xe-12mentioning

confidence: 99%

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

Urban

2004

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Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantummechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics.The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nu-2 clei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy.The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an encoding module for the recently developed NMR remote detection experiment. The feasibility of using hyperpolarized xenon-129 gas as a sensor is discussed. This work also reports the use of an optical atomic magnetometer to detect the nuclear magnetization of Xe-129 gas, which has potential applicability as a detection module for NMR remote detection experiments.

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Section: Heteronuclear Ddf Indirect Detection Experiments Using Xe-12mentioning

confidence: 99%

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

Urban

2004

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“…The two signals were then combined in a mixer [11], creating a dc signal whose amplitude was proportional to the power of the original microwave signal, and hence proportional to the power entering the horn. 2 If an attenuating material (in our case a dielectric liquid) is placed between the horn and the resonance cell, the microwave power reaching the Rb atoms will be reduced. As a consequence, the atomic candle will feed a correction signal back to the VCA that just compensates for this attenuation: The magnitude of the attenuated power is therefore detected as an increase in the microwave power supplied to the horn.…”

Section: B Measurements Of Electromagnetic Field Transmissionmentioning

confidence: 99%

“…For example, in quantum optics, the QED interaction between a colored vacuum and a quantum system can be probed by examining the intensity of light transmitted through a high-Q cavity [1]. In atomic physics, the transmission of light through a resonant vapor can be used to measure atomic collision cross sections [2], while in analytical chemistry, transmitted light can reveal the presence of trace compounds [3]. New means for precisely measuring both the relative and absolute strength of an electromagnetic field, especially ones with advantageous and unique characteristics, are therefore of considerable relevance for a great many researchers.…”

Section: Introductionmentioning

confidence: 99%

Precision measurements of absorption and refractive-index using an atomic candle

Swan-Wood

Coffer

Camparo

2001

IEEE Trans. Instrum. Meas.

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Public reporting burden tor this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden SPONSOR/MONITOR'S REPORT NUMBER(S)SMC-TR-02-18 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited. SUPPLEMENTARY NOTES ABSTRACTAcross a broad range of disciplines, the accurate determination of an electromagnetic wave's amplitude (either absolute or relative) has considerable relevance. Here, we demonstrate a novel and potentially very precise method for making intensity measurements based on the atomic stabilization of electromagnetic field-strength. For ease of reference, and by analogy to atomic clocks, we refer to this field-strength stabilization system as an atomic candle. While the candle's original purpose was to create a field with long-term intensity stability, its very nature makes it ideal for detecting subtle amplitude changes in strong electromagnetic fields, a problem that is fundamentally different from detecting weak signals in the presence of noise. In this paper, we discuss proof-of-principle experiments demonstrating the atomic candle's ability to make precise measurements of absorption coefficients and indices of refraction. Abstract-Across a broad range of disciplines, the accurate determination of an electromagnetic wave's amplitude (either absolute or relative) has considerable relevance. Here, we demonstrate a novel and potentially very precise method for making intensity measurements based on the atomic stabilization of electromagnetic field-strength. For ease of reference, and by analogy to atomic clocks, we refer to this field-strength stabilization system as an atomic candle. While the candle's original purpose was to create a field with long-term intensity stability, its very nature makes it ideal for detecting subtle amplitude changes in strong electromagnetic fields, a problem that is fundamentally different from detecting weak signals in the presence of noise. In this paper, we discuss proof-of-principle experiments demonstrating the atomic candle's ability to make precise measurements of absorption coefficients and indices of refraction. SUBJECT TERMS

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“…S 2 S ? S͒ [17], where R is the internuclear separation. Averaging over the rapid molecular rotation changes this to V SS l 3 ͓S ?…”

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confidence: 99%

Field Dependence of Spin Relaxation in a Dense Rb Vapor

1998

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We observe that the Rb-Rb relaxation rate for spin polarized Rb is reduced by a factor of 3 in magnetic fields of a few kG, even at multiatmosphere buffer gas pressures. This reduction is proportional to the Rb density and is independent of buffer gas pressure between 100 and 3000 Torr. We also report anomalously large relaxation rates below 100 Torr. Both of these observations are inconsistent with the previously held assumption that the Rb-Rb relaxation arises from sudden binary collisions.[S0031-9007(98)06437-0] PACS numbers: 32.80. Bx, 32.80.Cy, 33.35. + r Spin-exchange optical pumping warrants study, both for the intrinsic interest in spin-dependent collisional processes, and to maximize the efficiency with which hyperpolarized (highly spin polarized) noble gas nuclei are produced. Large scale, efficient polarization of noble gas nuclei is vital to such applications as polarized 3 He targets for nuclear and particle experiments [1], and magnetic resonance imaging [2].The key collisional processes in spin-exchange optical pumping are spin-exchange collisions between optically pumped alkali atoms and the noble gas atoms, and spin relaxation of the alkali atoms during collisions with each other, the noble gas atoms, or other buffer species present. The ratio of the spin-exchange to spin-relaxation rate determines the maximum efficiency possible for the spin-exchange process [3]. In this Letter, we report that the polarization loss due to Rb-Rb interactions is reduced from its zero-field rate by a factor of 3 in a few kG magnetic field. This field dependence persists even up to multiatmosphere buffer gas pressures. Since Rb-Rb relaxation accounts for a significant fraction of the polarization loss in 3 He spin-exchange optical pumping [4], our results suggest a straightforward way to increase optical pumping efficiency, and they require a new interpretation of the relaxation mechanism.For a variety of technical reasons most current spinexchange optical pumping experiments use Rb atoms as the alkali spin-exchange agent, so Rb relaxation rates are of particular interest. Previous evidence, obtained through study of the temperature and pressure dependence of the relaxation rates, is consistent with the interpretation that Rb relaxation occurs during sudden binary collisions with other Rb atoms, N 2 molecules (which are present to eliminate depolarization due to radiation trapping), and the noble-gas atoms [4][5][6]. If the Rb spin relaxation occurs only during binary collisions (as opposed to molecular formation, for example), the average collision time of t ϳ 1 psec implies that laboratory magnetic fields on the order of 1 kG should have no detectable effect on the relaxation. This is because the Larmor frequency of V m B B͞h 2p 3 2.8 GHz gives Vt ø 1, so there is negligible precession of the electron spin about the applied magnetic field during the collision.Contrary to the above expectations, we observe a reduction of Rb-Rb relaxation rates in kG magnetic fields. In addition, we find that at buffer gas pressu...

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Spin Destruction in Collisions between Cesium Atoms

Cited by 53 publications

References 21 publications

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

Precision measurements of absorption and refractive-index using an atomic candle

Field Dependence of Spin Relaxation in a Dense Rb Vapor

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