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1.
H. W. Cho D. J. McCarron D. L. Jenkin M. P. Köppinger S. L. Cornish 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,65(1-2):125-131
We report the production of a high phase-space density mixture of 87Rb and 133Cs atoms in a levitated crossed optical dipole trap as the first step towards the creation of ultracold RbCs molecules via magneto-association. We present a simple and robust experimental setup designed for the sympathetic cooling of 133Cs via interspecies elastic collisions with 87Rb. Working with the |F = 1,m F = +1〉 and the |3, +3〉 states of 87Rb and 133Cs respectively, we measure a high interspecies three-body inelastic collision rate ~10?25?10?26 cm6 ? s?1 which hinders the sympathetic cooling. Nevertheless by careful tailoring of the evaporation we can produce phase-space densities near quantum degeneracy for both species simultaneously. In addition we report the observation of an interspecies Feshbach resonance at 181.7(5) G and demonstrate the creation of Cs2 molecules via magneto-association on the 4(g)4 resonance at 19.8 G. These results represent important steps towards the creation of ultracold RbCs molecules in our apparatus. 相似文献
2.
D. L. Jenkin D. J. McCarron M. P. Köppinger H. W. Cho S. A. Hopkins S. L. Cornish 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,65(1-2):11-18
We report an apparatus and method capable of producing Bose-Einstein condensates (BECs) of ~1 × 106 87Rb atoms, and ultimately designed for sympathetic cooling of 133Cs and the creation of ultracold RbCs molecules. The method combines several elements: (i) the large recapture of a magnetic quadrupole trap from a magneto-optical trap; (ii) efficient forced RF evaporation in such a magnetic trap; (iii) the gain in phase-space density obtained when loading the magnetically trapped atoms into a far red-detuned optical dipole trap, and (iv) efficient evaporation to BEC within the dipole trap. We demonstrate that the system is capable of sympathetically cooling the |F = 1, m F = ?1〉 and |1,0? sublevels with |1, +1〉 atoms. Finally we discuss the applicability of the method to sympathetic cooling of 133Cs with 87Rb. 相似文献
3.
D. Ciampini E. Courtade C. Sias D. Cossart G. Carelli F. Mango O. Morsch E. Arimondo 《Optics Communications》2006,257(2):340-348
We used microwave radiation to evaporatively cool a mixture of of 133Cs and 87Rb atoms in a magnetic trap. A mixture composed of an equal number (around 104) of Rb and Cs atoms in their doubly polarized states at ultracold temperatures was prepared. We also used microwaves to selectively evaporate atoms in different Zeeman states. 相似文献
4.
Małgorzata Kasprzak 《Hyperfine Interactions》2016,237(1):142
Advances in experimental searches for a neutron Electric Dipole Moment (nEDM, d n ) are motivated by the potential discovery of a new source of CP violation beyond the Standard Model of particle physics. The nEDM experiment at the Paul Scherrer Institute (PSI), which with accumulated sensitivity of 1.09 × 10?26 e?cm (September 2016) is currently the most sensitive nEDM experiment worldwide, uses the Ramsey technique of separated oscillatory fields applied to stored ultracold neutrons. The nEDM measurements depend upon precise information about the magnetic field, which is monitored by a 199Hg co-magnetometer and an array of 133Cs magnetometers. The principle of the magnetic field measurement is based on the optical detection of the Larmor precession frequency of atoms polarized by optical pumping. In this article we present the recent progress of the nEDM experiment as well as details of a magnetic field measurements with special focus on the laser-operated array of high-sensitivity 133Cs magnetometers. 相似文献
5.
The formation of ultracold metastable RbCs molecules is observed in a double species magneto-optical trap through photoassociation below the 85Rb(5S1/2) + 133Cs(6P3/2) dissociation limit followed by spontaneous emission. The molecules are detected by resonance enhanced two-photon ionization. Using accurate quantum chemistry calculations of the potential energy curves and transition dipole moment, we interpret the observed photoassociation process as occurring at short internuclear distance, in contrast with most previous cold atom photoassociation studies. The vibrational levels excited by photoassociation belong to the 5th 0+ or the 4th 0? electronic states correlated to the Rb(5P1/2, 3/2) + Cs(6S1/2) dissociation limit. The computed vibrational distribution of the produced molecules shows that they are stabilized in deeply bound vibrational states of the lowest triplet state. We also predict that a noticeable fraction of molecules is produced in the lowest level of the electronic ground state. 相似文献
6.
7.
We report on the trapping of radioactive atoms for a variety of nuclear, atomic, and applied physics investigations. To date
we have trapped 5 different radioisotopes of rubidium and cesium (82–84Rb+135,137Cs) using a magneto-optical trap (MOT) coupled to a mass separator. By optimizing the efficiency of this system, we have been
able to trap as many as 6 million radioactive atoms and detect as few as 100. This technology is being applied in three different
areas: (1) the parity-violating, β-decay asymmetry measurement of polarized 82Rb; (2) the study of ultracold fermionic 84Rb atoms; and (3) the use of MOTs for the ultrasensitive detection of selected radioactive species. Although all of these
projects are in a formative stage of development, we highlight the progress that we have made in: (1) the trapping of 82Rb atoms in double MOT system; (2) the hyperfine structure measurement of the 5P1/2 and 5P3/2 levels in 82Rb; (3) the simultaneous trapping of 84Rb and 87Rb in overlapping MOTs; and (4) the first trapping and isotopic ratio measurement of 135Cs and 137Cs in a MOT.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
M.D. Di Rosa S.G. Crane J.J. Kitten W.A. Taylor D.J. Vieira X. Zhao 《Applied physics. B, Lasers and optics》2003,76(1):45-55
We report the first magneto-optical trapping of radioactive 135Cs and 137Cs and a promising means for detecting these isotopes at ultra-sensitive levels by coupling a magneto-optical trap (MOT) to
a mass separator. A sample containing both isotopes was placed in the source of a mass separator, ionized, mass-separated,
and implanted in a Zr foil within the trapping cell. After implantation, atoms were released from the foil by inductive heating
and then captured in a MOT that used large-diameter beams and a dry-film-coated cell to achieve high trapping efficiency.
Trapped-atom numbers in the case of either isotope ranged from 104 to 107, as determined from the MOT fluorescence signal. Over this trapped-atom range, the MOT fluorescence signal was found to increase
linearly with the number of atoms implanted in the foil and without isotopic bias to within 4%. In principle, this method
can then provide a measurement of the 137Cs/135Cs ratio accurate to within 4% through the direct ratio of MOT fluorescence signals. The fluorescence signal from stable 133Cs, when implanted and released from the foil, was suppressed relative to MOT signals by more than seven orders of magnitude
when the system was tuned to trap 135Cs or 137Cs. When combined with the isotopic selectivity of ≥105 for the mass separator, the overall suppression of 133Cs is expected to exceed 1012. At present our system delivers atoms from sample to MOT with an efficiency of 0.5%, has a trapped-atom detection limit of
4000 atoms, and achieves a sample-detection sensitivity of one million atoms.
Received: 23 August 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. Fax: +1-505/667-0440, E-mail: mdd@lanl.gov 相似文献
9.
The resonance frequencies and relaxation mechanisms of Cs2CuBr4 and Cs2ZnBr4 were examined by static nuclear magnetic resonance (NMR) method. Here, the two inequivalent Cs(1) and Cs(2) sites surrounded by Br ions were distinguished. The saturation recovery traces for 133Cs nuclei in Cs2CuBr4 with the paramagnetic ions, and those in Cs2ZnBr4 without the paramagnetic ions were each fitted by four exponential functions. From these results, the spin–lattice relaxation times T1 in the laboratory frame of 133Cs nuclei in the two crystals were obtained, and Cs(1) surrounded by 11 bromide ions has a longer relaxation time than Cs(2) surrounded by 9 bromide ions. 相似文献
10.
The relaxation times of the 1H and 133Cs nuclei in CsH3(SeO3)2 crystals were investigated using FT NMR. The 133Cs spectrum does change from seven resonance lines to one resonance line near Tm (=350 K). The presence of only one 133Cs signal is due to the liquid state resulting from the melting of the crystal. The variation in the separation of the 133Cs resonance lines with temperature indicates that the EFG at the Cs sites produced by the (SeO3)2− groups varies with temperature, which in turn means that the atoms neighboring 133Cs are displaced. And, the T1 for 133Cs is very long and undergoes significant changes near Tm. The change in the temperature dependence of T1 at Tm for the 133Cs nuclei coincides with the melting temperature. These results are compared with those obtained for MH3(SeO3)2 (M=Na, K, and Cs) crystals. 相似文献
11.
Photoassociation of ultracold atoms induced by chirped picosecond pulses is analyzed in a non-perturbative treatment by following the wavepacket dynamics on the ground and excited surfaces. The initial state is described by a Boltzmann distribution of stationary continuum states. The chosen example is photoassociation of cesium atoms at temperature
K from the
continuum to bound levels in the external well of the 0
g
-(6s + 6p
3/2) potential. We study how the modification of the pulse characteristics (carrier frequency, duration, linear chirp rate and intensity) can enhance the number of photoassociated molecules and suggest ways of optimizing the production of stable molecules.Received: 30 June 2004, Published online: 23 November 2004PACS:
33.80.Ps Optical cooling of molecules; trapping - 33.80.-b Photon interactions with molecules - 33.90. + h Other topics in molecular properties and interactions with photons - 33.80.Gj Diffuse spectra; predissociation, photodissociation 相似文献
12.
133Cs (I=7/2) nuclear magnetic resonance in a Cs2CuCl4 single crystal grown by using the slow evaporation method was measured in its three mutually perpendicular crystal planes. The 133Cs resonances of two different groups with two crystallographically inequivalent cesium nuclei, Cs(I) and Cs(II), in the unit cell were recorded. The transferred hyperfine fields for Cs(I) and Cs(II) calculated from the paramagnetic shift and the molecular susceptibility measurements could be expressed by the linear equation Hhf=AT+B. The angular dependence of the 133Cs nuclear magnetic resonance spectra showed that the Cs(I) and the Cs(II) nuclei had different values for the quadrupole coupling constant. The electric field gradient tensors of Cs(I) and Cs(II) were symmetric, and the orientations of their principal axes did not coincide. The Cs(I) ion surrounded by 11 chlorine ions had a small quadrupole parameter, a smaller charge distribution, and a small value for the transferred hyperfine field. However, the Cs(II) ion surrounded by nine chlorine ions had a larger quadrupole parameter, a larger charge distribution, and a larger value for the transferred hyperfine field. 相似文献
13.
G.Q. Li P. Peng 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,64(1):79-84
We investigate the conversion of ultracold bosonic atoms to heteronuclear tetramer
A3B by an Efimov resonance-assisted stimulated Raman adiabatic passage
scheme. In view of recent experiments involving heteronuclear Efimov trimers KKRb and
KRbRb [Phys. Rev. Lett. 103, 043201 (2009)], the intermediate state populated
by heteronuclear trimer A2B in the conversion process is considered. The
atom-molecule dark state solution for a system with a population imbalance is derived
analytically, and the role played by the imbalance in the conversion is studied. In
addition, the effects of the external field parameters (including photoassociated pulse
intensity, width, magnetic coupling strength and its detuning) on the conversion are
discussed via the concept of adiabatic fidelity. 相似文献
14.
Tomas Fritioff Conny Carlberg Guilhem Douysset Reinhold Schuch Ingmar Bergström 《Hyperfine Interactions》2001,132(1-4):229-242
The Penning trap mass spectrometer SMILETRAP has been considerably improved during the last two years. The helium pressure
has been carefully stabilized and is now independent of irregular air pressure. The temperature of the hyperboloidal precision
trap is stabilized to ±0.03°C. Remaining temperature instabilities are compensated by changes in the current of a warm coil
surrounding the precision trap. The frequency synthesizer is now locked to GPS. This means that it is much easier to accurately
measure resonances during several days. The improvements have demonstrated that in mass doublet measurements with an excitation
time of 1 s it is possible to determine the mass of ions with q/A=1/2 at an uncertainty to a few times of 0.1 ppb, using selected rather than cooled ions. In routine measurements lasting
for one day it is possible to reach a mass uncertainty of 1 ppb. The masses of the following particles and atoms have been
measured with uncertainties in the region 0.3–2 ppb: p, 3H, 3He, 4He, 22Ne, 28Si, 36Ar, 76Ge, 76Se, 86Kr and 133Cs. It has also been shown that though we are using a warm bore the trap pressure is sufficiently low to prevent electron
capture from the rest gas for excitation times of 3 s and for ion charges as high as 50+.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
C.M. Dion O. Dulieu D. Comparat W. de Souza Melo N. Vanhaecke P. Pillet R. Beuc S. Milošević G. Pichler 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):365-370
We present the results of absorption measurements in a cesium vapor around 630 K, together with photoionization spectra through
a resonance-enhanced two-photon absorption of ultracold cesium dimers created after photoassociation of ultracold cesium atoms.
The maximum efficiency of the ultracold molecule ionization is found for wavelengths where absorption at thermal energies
is the strongest, in agreement with our theoretical simulations of both processes, involving the so-called Cs2 diffuse bands. This result will be helpful for further optimization of such a direct way of detection of ultracold molecules.
Received 13 September 2001 相似文献
16.
17.
Wang LiRong Ma Jie Ji WeiBang Wang GuiPing Xiao LianTuan Jia SuoTang 《中国科学G辑(英文版)》2008,51(2):147-156
In this paper, an ultra-high resolution photoassociation spectroscopy study on photoassociation of cesium atoms is reported.
The cold cesium gas in the magneto-optical trap is illuminated by a photoassociation laser with red-tuning as large as 40
cm−1 below the 6S
1/2 + 6P
3/2 dissociation limit, and the photoassociation to the excited state ultracold molecule is detected. High signal-to-noise ratio
is obtained by using the lock-in detection of the fluorescence from the modulated cold Cs atoms. The 0
g
−
, 1g and 0
u
+
long-range states which correspond to 6S
1/2 + 6P
3/2 dissociation limit are present in the photoassociation spectrum. The effective coefficients of leading long-range interactions
and the corresponding vibrational quantum number are obtained using LeRoy-Bernstein Law. It is found that photoassociation
process creates rotating molecules and the high J value is a hint that higher partial waves participate in the PA process in the presence of trapping laser.
Supported by 973 Program of China (Grant. No. 2006CB921603), the National Natural Science Foundation of China (Grant Nos.
10574084, 60678003, and 60778008), the Special Foundation for State Major Basic Research Program of China (Grant No. 2005CCA06300),
and the Youth Science Foundation of Shanxi Province of China (Grant No. 20041013) 相似文献
18.
J. R. Garbin D. M. B. P. Milori D. V. Magalhães M. Anwar M. Ahmed A. Bebeachibuli S. T. Müller V. S. Bagnato 《Laser Physics》2008,18(2):144-148
Laser cooling and trapping of neutral atoms has been employed for the measurement of the total electron impact cross sections of the ground state 62 S 1/2 of 133Cs atoms in the energy range from 80 to 500 eV. The total electron impact cross sections of the cold Cs atoms in the MOT were measured by observing the decay of the MOT after the interaction with the electron beam, and were found to depend only on the electron flux and not on the total number of atoms in the MOT. We confirm and extend the existing data on these measurements. 相似文献
19.
S. Nakayama 《Optics Communications》1984,50(1):19-25
Theoretical calculation of 85Rb and 133Cs D1 signals in polarization spectroscopy is presented by using the method of velocity-selective optical pumping in a four-level system. Since good agreement between theory and experiment has been found in Na D1 polarized signals, the theoretical calculation can be also applied to Rb and Cs D1 lines. Rb and Cs atoms have higher total angular momentum F in the hyperfine structures than Na atom and then the calculation is more complicated. The relative signal intensities in polarization spectroscopy are compared with those in saturation spectroscopy. 相似文献