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1.
X.-G. Wang S.-H. Pan G.-Z. Yang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,10(3):415-422
We study the nonclassical properties and algebraic characteristics of the negative binomial states introduced by Barnett recently.
The ladder operator formalism and displacement operator formalism of the negative binomial states are found and the algebra
involved turns out to be the SU(1,1) Lie algebra via the generalized Holstein-Primarkoff realization. These states are essentially Perelomov's SU(1,1) coherent states. We reveal their connection with the geometric states and find that they are excited geometric states.
As intermediate states, they interpolate between the number states and geometric states. We also point out that they can be
recognized as the nonlinear coherent states. Their nonclassical properties, such as sub-Poissonian distribution and squeezing
effect are discussed. The quasiprobability distributions in phase space, namely the Q and Wigner functions, are studied in detail. We also propose two methods of generation of the negative binomial states. d
32.80.Pj Optical cooling of atoms; trapping
Received 8 May 1999 and Received in final form 8 November 1999 相似文献
2.
M. Dakna L. Knöll D.-G. Welsch 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(3):295-308
State preparation via conditional output measurement on a beam splitter is studied, assuming the signal mode is mixed with a mode prepared in a
Fock state and photon numbers are measured in one of the output channels. It is shown that the mode in the other output channel
is prepared in either a photon-subtracted or a photon-added Jacobi polynomial state, depending upon the difference between
the number of photons in the input Fock state and the number of photons in the output Fock state onto which it is projected.
The properties of the conditional output states are studied for coherent and squeezed input states, and the probabilities
of generating the states are calculated. Relations to other states, such as near-photon-number states and squeezed-state-excitations,
are given and proposals are made for generating them by combining the scheme with others. Finally, effects of realistic photocounting
and Fock-state preparation are discussed.
Received: 17 March 1998 / Revised and Accepted: 8 May 1998 相似文献
3.
F. Plastina F. Piperno 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(3):411-415
We propose a simple method to obtain a superposition of coherent states on a circle, including Schr?dinger cat states as a
special case, via conditional measurement of the state of three level atoms interacting with a one mode cavity field. In the low amplitude
limit, very good approximation of Fock states can also be generated in this way.
Received: 8 October 1998 / Accepted: 30 October 1998 相似文献
4.
Z.-C. Wang Z.-Y. Chen Y. Xu 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,4(2):185-190
A theoretical study is made of the steady-state populations of a three-level atom in a ladder configuration, driven by a superposition
of a monochromatic laser wave with a broad-band squeezed vacuum. The master equation for the system and the atomic Bloch equations
are derived. The steady-state populations are calculated numerically and shown graphically as functions of two-photon detuning
for various cases of the squeezed vacuum. It is shown that, the atomic populations depend strongly on the relative phase of
the driving field and the squeezed vacuum. When the phase matching condition is fulfilled, there will be a strong two-photon
resonant absorption from the squeezed vacuum, a characteristic different from absorption of photons from a classical field.
Received: 28 May 1997 / Revised and Accepted: 10 December 1997 相似文献
5.
H.-y. Fan A. Wünsche 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(3):405-412
We examine the existence of right-hand eigenstates (or eigenkets) of the boson creation operator a
and determine their coordinate and their Bargmann representation. The eigenkets of the creation operator are ultrasingular
and cannot be considered as a limiting case of normalizable states. Applications of these eigenstates as auxiliary states
for purposes of representation of states by path integrals over coherent states are discussed. A completeness relation for
coherent states on paths through the complex plane is derived and special examples of its application are considered.
Received 9 March 2001 and Received in final form 13 June 2001 相似文献
6.
Summary The atomic-dipole squeezing condition for arbitrarily prepared atomic and field states in multi-photon Jaynes-Cummings model
was derived. Three special cases were discussed. For the field initially in a vacuum state and a certain eigenstate of the
Susskind-Glogower phase operator, the analytical dipole squeezing conditions were obtained and the maximum squeezing values
were calculated. For a squeezed vacuum input field, the dipole squeezing behaviours under the influence of the field squeezing
parameterr and the phased atom were numerically treated. 相似文献
7.
E. Cormier P. Lambropoulos 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,2(1):15-20
We report on observable new features related to ionization of atoms by laser pulses of only few cycles and some intensity.
We show that for particular photo-electron energies, the angular distribution becomes asymmetric and that this asymmetry is
related to the initial phase of the field.
Received: 4 November 1997/Revised: 21 January 1998/Accepted: 23 February 1998 相似文献
8.
Shi-Biao Zheng Guang-Can Guo 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,1(1):105-107
We propose a method for preparing superpositions of coherent states of the motion of an ion in an anisotropic two-dimensional
trap, in which the ion is tightly bound in the y direction. In the scheme the ion is excited by two resonant laser beams with equal amplitude, propagating along the x and y directions, respectively. In the Dicke-Lamb limit, an initial coherent state of the ion motion can be converted into a superposition
of several coherent states on a circle through the laser-ion interactions and state-selective measurements on the ion.
Received: 30 May 1997 / Revised: 29 July 1997 / Accepted: 22 October 1997 相似文献
9.
S.-y. Xie Y.-p. Yang X. Wu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(1):129-143
We study the spontaneous emission properties of a V-type three-level atom embedded in a photonic crystal with the anisotropic
dispersion relation. We show that the localized field can disappear and the diffusion field can become intense in some regions.
This originates from no singularity of the density of states. The quantum interference leads to oscillatory, quasi-oscillatory
or complete decay behavior of population. The complete decay can also be realized in certain condition without depending on
the initial state.
Received 9 April 2000 and Received in final form 1st August 2000 相似文献
10.
Paulina Marian Tudor A. Marian 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):257-265
We analyze the transient nonclassical behaviour of a single-mode field whose interaction with an environment is governed by
the quantum optical master equation. Our analytic method makes use of the generalized characteristic function of the field
state. First, we find a time at which all squeezing effects disappear by decoherence regardless of the initial state of the
mode. In the case of an input even coherent state, an unusual modification of higher-order squeezing at low values of thermal
mean occupancy transferred to the field is found and discussed. For the same initial state, we also perform a comprehensive
analysis of the mixing process during the interaction with the reservoir. We prove that a maximum in the evolution of the
2-entropy of the attenuated mode exists on condition that its initial mean photon number exceeds the mean occupancy of the
reservoir. This transient mixing enhancement can be considered as a quantum effect of the initial state on the mode damping.
Received 22 April 1999 and Received in final form 2 November 1999 相似文献
11.
Wang Kaige A. Sinatra L.A. Lugiato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(2):339-349
We present a simple method, based on the quantum regression theorem, to calculate the quantum correlation spectra for two
optical beams in the linearized fluctuation regime. As an application, we discuss the dynamical instability, the squeezing
spectra and the QND properties of a crossed Kerr-type dispersive model.
Received 30 August 1999 and Received in final form 4 July 2000 相似文献
12.
X.-M. Hu J.-S. Peng 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(2):291-299
On the basis of the nondegenerate quantum-beat laser model, we introduce a coherent field which drives the transition between the upper lasing level and an
auxiliary level. We demonstrate that such a four-level system can produce squeezed two-mode laser without and with inversion.
When the laser is operated well above threshold, the intensity fluctuation in the average mode is reduced below the shot noise
with an optimum Mandel parameter Q=- 1/2. At the same time, the noises in the relative amplitude and the relative phase drop to their vaccum noise levels. Furthermore,
regardless of inversion, noninversion, and transition between inversion and noninversion, the optimum Mandel Q parameter of Q=- 1/2 is retained when the system operates well above threshold. A simple physical explanation of the squeezing mechanism
for two-mode squeezing is given.
Received: 22 December 1997 / Revised: 25 March 1998 / Accepted: 9 September 1998 相似文献
13.
R. Migliore A. Messina A. Napoli 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(3):585-588
We prove that a mesoscopic Josephson junction, irradiated with a quantum superposition of two -out of phase optical coherent states, exhibits an experimentally observable sensitivity to the quantum coherences of the
field state.
Received 1 June 1999 and Received in final form 30 July 1999 相似文献
14.
A. Luis L.L. Sánchez-Soto 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(2):195-200
We reconsider the problem of the sum and difference of two angle variables in quantum mechanics. The spectra of the sum and
difference operators have widths of , but angles differing by are indistinguishable. This means that the angle sum and difference probability distributions must be cast into a range. We obtain probability distributions for the angle sum and difference and relate this problem to the representation
of nonbijective canonical transformations.
Received: 6 December 1997 / Revised: 15 April 1998 / Accepted: 7 May
1998 相似文献
15.
U. Leonhardt T. Kiss P. Piwnicki 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):413-423
Impressive pictures of moving Bose-Einstein condensates have been taken using phase-contrast imaging [M.R. Andrews et al., Science 273, 84 (1996)]. We calculate the quantum backaction of this measurement technique, assuming the absence of residual absorption.
We find that the condensate gets gradually depleted at a universal rate that is proportional to the light intensity and to
the inverse cube of the optical wave length. The fewer atoms are condensed the higher is the required intensity to see a picture,
and, consequently, the higher is the induced backaction. To describe the quantum physics of phase-contrast imaging we put
forward a new approach to quantum-optical propagation. We develop an effective field theory of paraxial optics in a fully
quantized atomic medium.
Received 25 February 1999 相似文献
16.
17.
C. Szwaj G.-L. Oppo A. Gatti L.A. Lugiato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,10(3):433-448
Quantum images, that is inhomogeneous field distributions purely generated by quantum fluctuations, persist when passing from
the degenerate to the non-degenerate case of optical parametric oscillators (OPO). Below the threshold for parametric oscillation
where the near-field distributions are homogeneous both in intensity and phase, appropriate spatial correlation functions
anticipate the transverse spatial pattern that appears above threshold. In particular, the angular dependence of the far field
spatial correlation function is able to reveal the travelling-wave nature of the phase pattern above threshold typical of
nondegenerate OPOs. Cross-correlation functions between signal and idler intensities show clear evidence of the non-classical
nature of the output light.
Received 8 October 1999 相似文献
18.
Faisal A.A. El-Orany J. Peřina V. Peřinová M. Sebawe Abdalla 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):141-156
The evolution of the Schr?dinger-cat states in a dissipative parametric amplifier is examined. The main tool in the analysis
is the normally ordered characteristic function. Squeezing, photon-number distribution and reduced factorial moments are discussed
for the single- and compound-mode cases. Also the single-mode Wigner function is demonstrated. In addition to the decoherence
resulting from the interaction with the environment (damped case) there are two sources which can cause such decoherence in
the system even if it is completely isolated: these are the decay of the pump and the relative phases of the initial cat states.
Furthermore, for the damped case there are two regimes, which are underdamped and overdamped. In the first (second) regime
the signal mode or the idler mode “collapses" to a statistical mixture (thermal field).
Received 25 September 2001 / Received in final form 30 May 2002 Published online 13 December 2002
RID="a"
ID="a"e-mail: sebaweh@awalnet.net.sa
RID="b"
ID="b"Joint Laboratory of Optics of Palacky University and Institute of Physics, Academy of Sciences of the Czech Republic,
17. listopadu 50, 772 07 Olomouc, Czech Republic. 相似文献
19.
R. Folman J. Schmiedmayer H. Ritsch D. Vitali 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(1):93-107
Following almost a century of debate on possible “independent of measurement" elements of reality, or “induced" elements of
reality - originally invoked as an ad-hoc collapse postulate, we propose a novel line of interference experiments which may be able to examine the regime of induced
elements of reality. At the basis of the proposed experiment, lies the hypothesis that models of “induced" elements of reality
should exhibit symmetry breaking within quantum evolution. The described symmetry experiment is thus aimed at being able to detect and resolve spatial symmetry breaking signatures. The proposed experiment stands at
the edge of present day technological abilities and will be, so we believe, realizable in the near future.
Received 2 December 1999 and Received in final form 6 April 2000 相似文献
20.
G.M. Abd Al-Kader 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,8(3):429-438
The s-parameterized characteristic function for the output field with the superposition of squeezed displaced Fock states (SDFS's)
as input field is given. The s-ordered distribution functions for the output field with superposition of SDFS's as input state are investigated. Various
moments are calculated by using the s-ordered characteristic function for that field. The Glauber second-order coherence function is calculated. The quadrature
squeezing for the output field are discussed. Some Quasiprobability distribution functions of the output fields are plotted
as functions of the interaction time. The quadrature squeezing for the output field are discussed.
Received 30 September 1998 相似文献