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1.
N. Gaaloul A. Jaouadi L. Pruvost M. Telmini E. Charron 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(3):343-351
We present a detailed, realistic proposal and analysis of the implementation of a cold atom deflector using time-dependent
far off-resonance optical guides. An analytical model and numerical simulations are used to illustrate its characteristics
when applied to both non-degenerate atomic ensembles and to Bose-Einstein condensates. Using for all relevant parameters values
that are achieved with present technology, we show that it is possible to deflect almost entirely an ensemble of 87Rb atoms falling in the gravity field. We discuss the limits of this proposal, and illustrate its robustness against non-adiabatic
transitions. 相似文献
2.
J.-F. Greisch B. Leyh E. De Pauw 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(1):89-96
We have studied magneto-optical traps (MOTs) for efficient on-line trapping of radioactive atoms. After discussing a model
of the trapping process in a vapor cell and its efficiency, we present the results of detailed experimental studies on Rb
MOTs. Three spherical cells of different sizes were used. These cells can be easily replaced, while keeping the rest of the
apparatus unchanged: atomic sources, vacuum conditions, magnetic field gradients, sizes and power of the laser beams, detection
system. By direct comparison, we find that the trapping efficiency only weakly depends on the MOT cell size. It is also found
that the trapping efficiency of the MOT with the smallest cell, whose diameter is equal to the diameter of the trapping beams,
is about 40% smaller than the efficiency of larger cells. Furthermore, we also demonstrate the importance of two factors:
a long coated tube at the entrance of the MOT cell, used instead of a diaphragm; and the passivation with an alkali vapor
of the coating on the cell walls, in order to minimize the losses of trappable atoms. These results guided us in the construction
of an efficient large-diameter cell, which has been successfully employed for on-line trapping of Fr isotopes at INFN’s national
laboratories in Legnaro, Italy. 相似文献
3.
Z. Y. Wang Z. Zhang Q. Lin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(2):127-131
In this paper, we proposed new constructions of atom interferometers manipulated through the toroidal trap formed by the interference
patterns of two co-propagation Laguerre-Gaussian (LG) beams. The coherent splitting and merging of the atomic ensemble, which
is essential for the atom interferometer, is realized by the interference pattern of two LG beams. Along the beam propagation
direction, a single-well trap is evolved into a double-well trap and then recombined back into a single-well trap, which can
be used to form an atom interferometer. 相似文献
4.
S. Gleyzes A. El Amili R. A. Cornelussen P. Lalanne C. I. Westbrook A. Aspect J. Estève G. Moreau A. Martinez X. Lafosse L. Ferlazzo J. C. Harmand D. Mailly A. Ramdane 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(1):107-111
We study a Fabry-Perot cavity formed from a ridge waveguide on a AlGaAs substrate. We experimentally determined the propagation
losses in the waveguide at 780 nm, the wavelength of Rb atoms. We have also made a numerical and analytical estimate of the
losses induced by the presence of the gap which would allow the interaction of cold atoms with the cavity field. We found
that the intrinsic finesse of the gapped cavity can be on the order of F∼30, which, when one takes into account the losses
due to mirror transmission, corresponds to a cooperativity parameter for our system C∼1. 相似文献
5.
P. Bushev S. Stahl R. Natali G. Marx E. Stachowska G. Werth M. Hellwig F. Schmidt-Kaler 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(1):97-102
We report on trapping of clouds of electrons in a
cryogenic planar Penning trap at T ≤100 mK. We describe the
experimental conditions to load, cool and detect electrons.
Perspectives for the trapping of a single electron and for quantum
information processing are given. 相似文献
6.
S. N. Shevchenko 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(2):187-191
The impedance measurement technique consists in that the phase-dependent
(parametric) inductance of the system is probed by the classical tank
circuit via measuring the voltage. The notion of the parametric inductance
for the impedance measurement technique is revisited for the case when a
quantum system is probed. Measurement of the quantum state of the system of
superconducting circuits (qubits) is studied theoretically. It is shown that the result of the
measurement is defined by the partial energy levels population in the qubits and by its derivative. 相似文献
7.
G. Stern B. Battelier R. Geiger G. Varoquaux A. Villing F. Moron O. Carraz N. Zahzam Y. Bidel W. Chaibi F. Pereira Dos Santos A. Bresson A. Landragin P. Bouyer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(3):353-357
We describe the operation of a light pulse interferometer using cold 87Rb atoms in reduced gravity. Using a series of two Raman transitions induced by light pulses, we have obtained Ramsey fringes
in the low gravity environment achieved during parabolic flights. With our compact apparatus, we have operated in a regime
which is not accessible on ground. In the much lower gravity environment and lower vibration level of a satellite, our cold
atom interferometer could measure accelerations with a sensitivity orders of magnitude better than the best ground based accelerometers
and close to proven spaced-based ones. 相似文献
8.
P. Rosenbusch 《Applied physics. B, Lasers and optics》2009,95(2):227-235
We investigate the hyperfine transition of magnetically trapped non-condensed atoms. The two principal frequency shifts, the
second order Zeeman effect and the mean field interaction are considered. Analytic models of the mean frequency and its trap
induced spread are developed. Comparisons with existing experiments evaluate the role of the atoms’ oscillatory motion. The
analytic model proves to be equivalent to existing Monte Carlo simulations. The formulae provide a simple tool for optimising
the design of a new experiment. Applied to the two-photon transition |F=1,m
F
=−1〉→|F=2,m
F
=1〉 in 87Rb and the conditions of a typical atom chip experiment, a line spread as small as 11 mHz is predicted giving a quality factor
of 1012. The system is promising for application in precision instruments such as compact atomic clocks. 相似文献
9.
T. David Y. Japha V. Dikovsky R. Salem C. Henkel R. Folman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,48(3):321-332
We analyze atom-surface magnetic interactions on atom chips where the magnetic trapping potentials are produced by current
carrying wires made of electrically anisotropic materials.
We discuss a theory for time dependent fluctuations of the magnetic potential, arising from thermal noise
originating from the surface. It is shown that using materials with a large electrical anisotropy results in a considerable
reduction of heating
and decoherence rates of ultra-cold atoms trapped near the surface, of up to several orders of magnitude. The trap
loss rate due to spin flips is expected to be significantly reduced
upon cooling the surface to low temperatures. In addition, the electrical anisotropy
significantly suppresses the amplitude of static spatial potential corrugations due to
current scattering within imperfect wires. Also the shape of the corrugation pattern depends on the electrical anisotropy:
the preferred angle of the scattered current wave fronts can be varied over a wide range. Materials, fabrication, and experimental
issues are discussed, and specific candidate materials are suggested. 相似文献
10.
A. R. Bulsara V. In A. Kho G. Anderson C. Obra P. Longhini J. Neff S. Baglio B. Ando A. Palacios 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(1):109-118
We consider the performance of a nonlinear dynamic device, operated as a threshold detector, in the time domain. The device
is characterized by a figure-of-merit that involves the mean residence times in its two stable steady states, as well as the
dispersion in this quantity stemming from a noise floor. As a particular example, we consider a coupled (overdamped) oscillator
system, the underpinnings of a coupled core magnetometer (CCM). We provide a detailed discussion of how the device is used,
in practice, to detect a weak dc target magnetic field, and explain the importance of characteristic time-scales in the problem
specifically the device time-constant, the noise correlation time and the observation time (to obtain an averaged reading
in the presence of noise). A device “Resolution” is introduced as a performance measure and is, analytically, computed under
specific (but realistic for practical applications) conditions. This measure is shown to be independent of the target signal;
in fact it depends only on the noise and device parameters, in the weak signal limit (that is of interest in most applications).
The resolution is seen to be analogous to the inverse of a response signal-to-noise ratio. 相似文献
11.
In order to find a non-commutative analog of Schwarzschild or Schwarzschild–de Sitter black hole we investigate spherically
symmetric spaces generated by four non-commutative coordinates in the frame formalism. We present two solutions which, however,
do not possess the prescribed commutative limit. Our analysis indicates that the appropriate non-commutative space might be
found as a subspace of a higher-dimensional space. 相似文献
12.
T. Müller M. Gilowski M. Zaiser P. Berg Ch. Schubert T. Wendrich W. Ertmer E. M. Rasel 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(3):273-281
We present a compact and transportable inertial sensor for
precision sensing of rotations and accelerations. The sensor consists
of a dual atom interferometer operated with laser-cooled 87Rb.
Raman processes are employed to coherently manipulate the matter
waves. We describe and characterize the experimental apparatus. A
method for passing from a compact geometry to an extended
interferometer with three independent atom-light interaction zones is
proposed and investigated. The extended geometry will enhance the
sensitivity by more than two orders of magnitude which is necessary
to achieve sensitivities better than 10-8rad/s/. 相似文献
13.
B. S. Tomar A. Goswami A. V. R. Reddy S. K. Das P. P. Burte S. B. Manohar Satya Prakash 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(2):223-227
Excitation functions for the evaporation residues for the reactions12C+93Nb and16O+89Y in the projectile energy range of 4 to 6.5 MeV/amu have been measured using off-line gamma spectrometry. The excitation functions for neutron(xn), proton(pxn) and one alpha(xn) emission channels are practically similar for both the reactions. However the products formed by two alpha(2xn) emission show much higher cross sections in the12C+93Nb than the16O+89Y system. This has been explained in terms of the incomplete fusion process involving transfer of an alpha particle from the projectile to the target in the former case.Authors thank Shri D.C. Ephraim for making the rolled metal foils and the operation crew of PELLETRON facility for their help in carrying out the irradiations. Authors are grateful to Dr. P.R. Natarajan, Head Radiochemistry Division for his keen interest in this work. 相似文献
14.
G. Mazzarella 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(1):61-66
We study mixtures of spinless bosons and not spin-polarized
fermions loaded in two dimensional optical lattices. We approach the problem of
the ground state stability within the framework of the linear response theory; by the mean of an
iterative procedure, we are able to obtain a relation for the dependence of boson-boson effective interaction on the absolute
temperature of the sample.
Proceeding from such a formula, we write down analytical expressions for
supersolid (SS) and phase separation (PS) transition temperatures, and plot the phase diagrams. 相似文献
15.
G. Filatrella A. Petraglia G. Rotoli 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,12(1):23-30
In this paper we investigate the behavior of moderate size two-dimensional classical arrays of Josephson junctions in presence
of an external oscillating field. We have included in the model the effects due to mutual inductance terms, and we have employed
an explicit set of differential equations. We have found that the discretization parameter - i.e. the coupling term due to the inductance of the loops - is the most important parameter to determine the height of the Shapiro
steps for a given amplitude and frequency of the rf-bias. The amplitude of the Shapiro steps in the case of zero frustration
as a function of the coupling term shows a remarkable minimum for intermediate values when we retain all terms of the full
model with mutual inductances, while the limits for very large and very small values of they are the same of the single Josephson junction. For the case of frustration 1/2 the Shapiro step becomes smaller in the
rigid limit (i.e., small ) as expected for the XY model, and tends to the limit value of the single junctions for the decoupled case (i.e., large ).
Received 9 November 1998 and Received in final form 6 April 1999 相似文献
16.
F. Aigner M. Hillbrand J. Knapp G. Milovanovic R. Schöfbeck M. Schweda V. Putz 《Czechoslovak Journal of Physics》2004,54(7):711-719
The possibility of a resummation procedure in order to cure the UV/IR-mixing problem of noncommutative field theories is discussed. The method is presented for a scalar φ4 theory on Euclidean space. Finally, we sketch the idea of resummation forU(1)-gauge theories. 相似文献
17.
M. Veselský Š. Šáro F. P. Heßberger V. Ninov S. Hofmann D. Ackermann 《Zeitschrift für Physik A Hadrons and Nuclei》1996,356(1):403-410
Velocity distributions and production cross sections of evaporation residues have been measured in the reaction20Ne+208Pb at projectile energies of 8.6, 11.4, 14.9 A.MeV. Essential deviations from statistical model of deexcitation have been
observed. Monte Carlo simulations involving emission of non-equilibrium particles have been used in order to reproduce experimental
velocity, charge and mass distributions of evaporation residues and to estimate indirectly multiplicities of pre-equilibrium
particles.
Communicated by V. Metag 相似文献
18.
C. P. Montoya S. Schadmand I. Diószegi D. J. Hofman P. H. Zhang P. Paul 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(4):371-375
The strength functions fore
+
e
– pair decay of the isoscalar and isovector giant monopole resonances in highly excited nuclei are derived and used in a statistical model calculation of thee
+
e
– pair energy spectrum from compound nuclear decay in110Sn following a fusion evaporation reaction. This result is then compared to thee
+
e
– spectrum derived from internal pair decay of the giant dipole and giant quadrupole resonances. The computation shows that the pair decay from the excited-state GDR dominates the pair spectrum over the region of all giant resonances, exceedingL=0 transitions by at least a factor of ten. We also compute the angular correlations betweene
+ ande
– for theL=0, L=1 andL=2 transitions and estimate their power to discriminate between the various multipolarities.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday 相似文献
19.
A. Scherdin A. Schäfer W. Greiner G. Soff P. J. Mohr 《Zeitschrift für Physik A Hadrons and Nuclei》1995,352(3):273-277
The emission of high-energy-rays in the deexcitation of hot40Ca and39K nuclei formed in heavy-ion fusion reactions at excitation energyE
x 90 MeV has been studied. The high energy-rays were measured in coincidence with evaporation residues or light charged particles. The spectrum from the self-conjugated compound nucleus40Ca shows an appreciable yield suppression in the Giant Dipole Resonance (GDR) energy region with respect to the39K, due to isospin selection rules in the dipole-decay. The spectral line shapes of the spectra are well reproduced by using a statistical code which treats explicitly the isospin quantum number in evaluating level densities and transmission coefficients. The GDR parameters determined from the present coincidence measurements are in good agreement with the systematic in theA 40 mass region at lower bombarding energy based on the analysis of inclusive spectra.We thank M. Caldogno for technical support in the development of evaporation residues detectors. We acknowledge the participation of M. Anghinolfi, P. Corvisiero, M. Taiuti and A. Zucchiatti in the early stages of this work. Thanks are due to M. Kicinska-Habior for providing the isospin-dependent code. Discussions with B. Fornal are also gratefully acknowledged. 相似文献
20.
L. Müller F. Soramel E. Adamides S. Beghini L. Corradi G. LoBianco B. Million M. Molho H. Moreno D. R. Napoli G. F. Prete F. Scarlassara G. F. Segato S. Signorelli C. Signorini P. Spolaore A. M. Stefanini 《Zeitschrift für Physik A Hadrons and Nuclei》1992,341(2):131-136
Superdeformed (SD) bands in152Dy,151Dy and151Tb have been populated via the 5n, 6n and 5np evaporation channels, respectively, with the33S+124Sn reaction at 160 and 170 MeV bombarding energies. Population intensities are in good agreement with existing data for SD bands in151, 152Dy and SD yrast band in151Tb. The excited twin SD band in151Tb with the same-transitions as the band in152Dy is populated about 5 times more strongly than by the 6n evaporation channel. This might be explained in terms of competition between proton and emission out of an intermediate, excited superdeformed configuration of152Dy.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday 相似文献