共查询到20条相似文献,搜索用时 15 毫秒
1.
We study the evolution of entangled coherent states of the two quantized electromagnetic fields under dissipation. Characteristic time scales for the decay of the negativity are found in the case of large values of the phase space distance among the states of each mode. We also study how the entanglement emerges among the reservoirs. 相似文献
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We have compared the non-linear wave packet dynamics of coherent states of various symmetry groups and found that certain generic features of non-linear evolution are present in each case. Thus the initial coherent structures are quickly destroyed but are followed by Schrödinger cat formation and revival. We also report important differences in their evolution. 相似文献
3.
We propose a scheme for implementing a probabilistic controlled-NOT (CNOT) gate for coherent state qubits using only linear optics and a particular four-mode state. The proposed optical setup works, as a CNOT gate, near-faithful when |α|2?25 and independent of the input state. The key element for realizing the proposed CNOT scheme is the entangled four-mode state. 相似文献
4.
A Coherent Spin State (CSS) is defined as an eigenstate of the spin component in the direction specified by angles (θ0,?0). This state satisfies minimum uncertainty relation, with uncertainties equally distributed on any two orthogonal components normal to the direction of the total spin vector 〈S〉. Starting from this concept, we apply the notion of CSS to quantum groups and discuss the properties of q-deformed CSS and the associated uncertainty relations. We show that these states behave as Intelligent Spin States (ISS) on two orthogonal components normal to the direction of the mean value of the spin operator. 相似文献
5.
O. Abbasi 《Optics Communications》2010,283(12):2566-2574
Nonlinear coherent states (CSs) and their dual families were introduced recently. In this paper, we want to obtain their superposition and investigate their non-classical properties such as antibunching effect, quadrature squeezing and amplitude squared squeezing. For this purpose two types of superposition are considered. In the first type, we neglect the normalization factors of the two components of the dual pair, superpose them and then we normalize the obtained states, while in the second type we superpose the two normalized components and then again normalize the resultant states. As a physical realization, the formalism will then be applied to a special physical system with known nonlinearity function, i.e., Hydrogen-like spectrum. We continue with the (first type of) superposition of the dual pair of Gazeau-Klauder coherent states (GKCSs) as temporally stable CSs. An application of the proposal will be given by employing the Pöschl-Teller potential system. The numerical results are presented and discussed in detail, showing the effects of this special quantum interference. 相似文献
6.
We introduce a new entangled quantum state generated by applying single-mode coherent superposition of photon subtraction and addition (a† cos θ + a sin θ)m to the entangled coherent state |Ψ±(α,0)〉, and then investigate the entanglement properties affected by coherent superposition operation. It is shown that this operation can be applied to enhance the entanglement of the state |Ψ+(α,0)〉. In addition, the effects of the coherent operation is better to improve the entanglement than that of the creation operation (a†m) for |Ψ+(α,0)〉 in a small-amplitude regime and for |Ψ−(α,0)〉 in any regime. 相似文献
7.
We present a theoretical analysis of the k-boson nonlinear coherent states of a two-level trapped ion interacting with two laser fields. Such states are both the zero-energy state of the interaction Hamiltonian and the eigenstates of a deformed annihilation operator. For the single-boson case, we show that the structure of the states and their coherence and minimum-uncertainty properties can be compromised whenever the Lamb-Dicke parameter is one of the roots of certain Laguerre polynomials. We investigate these problems, which are strictly related to the non-analyticity of the deformation function in the annihilation operator. 相似文献
8.
A simple way to find solutions of the Painlevé IV equation is by identifying Hamiltonian systems with third-order differential ladder operators. Some of these systems can be obtained by applying supersymmetric quantum mechanics (SUSY QM) to the harmonic oscillator. In this work, we will construct families of coherent states for such subset of SUSY partner Hamiltonians which are connected with the Painlevé IV equation. First, these coherent states are built up as eigenstates of the annihilation operator, then as displaced versions of the extremal states, both involving the related third-order ladder operators, and finally as extremal states which are also displaced but now using the so called linearized ladder operators. To each SUSY partner Hamiltonian corresponds two families of coherent states: one inside the infinite subspace associated with the isospectral part of the spectrum and another one in the finite subspace generated by the states created through the SUSY technique. 相似文献
9.
Armando Perez-Leija Hector Moya-Cessa Omar Aguilar-Loreto 《Optics Communications》2011,284(7):1833-1836
We show that light evolution occurring in waveguide arrays with a particular n-functional square root dependence of coupling coefficients can be used to produce classical analogues of nonlinear quantum coherent states. Using operator algebras we obtain closed-form expressions describing the optical field dynamics in such structures. In addition, by numerically monitoring the Mandel's parameter, we obtain the conditions necessary to generate sub-Poissonian and super-Poissonian classical intensity distributions in the proposed photonic lattices. 相似文献
10.
We consider the quantum dynamics of a charged particle evolving under the action of a constant homogeneous magnetic field, with emphasis on the discrete subgroups of the Heisenberg group (in the Euclidean case) and of the SL(2,R) group (in the Hyperbolic case). We investigate completeness properties of discrete coherent states associated with higher order Euclidean and hyperbolic Landau levels, partially extending classic results of Perelomov and of Bargmann, Butera, Girardello and Klauder. In the Euclidean case, our results follow from identifying the completeness problem with known results from the theory of Gabor frames. The results for the hyperbolic setting follow by using a combination of methods from coherent states, time-scale analysis and the theory of Fuchsian groups and their associated automorphic forms. 相似文献
11.
Isiaka Aremua Mahouton Norbert Hounkonnou Ezinvi Baloïtcha 《Journal of Nonlinear Mathematical Physics》2014,21(1):89-119
This work addresses a construction of a dual pair of nonlinear coherent states (NCS) in the context of changes of bases in the underlying Hilbert space for a model pertaining to an electron-phonon model in the condensed matter physics, obeying a f-deformed Heisenberg algebra. The existence and properties of reproducing kernel in the NCS Hilbert space are studied and discussed; the probability density and its dynamics in the basis of constructed coherent states are provided. A Glauber-Sudarshan P-representation of the density matrix and relevant issues related to the reproducing kernel properties are presented. Moreover, a NCS quantization of classical phase space observables is performed and illustrated in a concrete example of q-deformed coherent states. Finally, an exposition of quantum optical properties is given. 相似文献
12.
We present a new approach to near-resonant coherent backscattering of light from cold two-level atoms. In the dilute regime, where the distance between atoms is much larger than the laser wavelength, this approach is able to account for multi-photon scattering processes between many atoms through solutions of single-atom optical Bloch equations. We elaborate the method for double scattering from two atoms, and discuss the way of its extension for dilute, cold atomic clouds. 相似文献
13.
We study the effects of two-parameter noises on rate oscillations during CO oxidation on platinum surface, in a parameter region sub-threshold to deterministic Hopf bifurcation. It is found that the performance of noise-induced oscillations, characterized by an effective signal-to-noise ratio, shows ridge shape in the DCO∼DO2 plane, where DCO and DO2 measure the strength of two different parameter noises. It is indicating that the ‘two-parameter coherent resonance’ phenomenon occurs. Stochastic normal form theory is employed to analyze the non-trivial effects of two-parameter noises and the simulation results are well reproduced. 相似文献
14.
Popp and Yan [F.A. Popp, Y. Yan, Phys. Lett. A 293 (2002) 93] proposed a model for delayed luminescence based on a single time-dependent coherent state. We show that the general solution of their model corresponds to a luminescence that is a linear function of time. Therefore, their model is not compatible with experimental delayed luminescence. Moreover, the functions that they use to describe the oscillatory behaviour of delayed luminescence are not solutions of the coupling equations to be solved. 相似文献
15.
We present a systematic study for generation of intense and short single as pulse in pre-excited He-ionic medium with the use of a same-frequency laser field synthesis. By preparing He+ ions in a coherent superposition of the ground and excited states, a depth of spectral modulation efficiently decreases and the efficiency of harmonic plateau increases. By means of optimizing the laser parameters, the broadband XUV supercontinuum achieve by the superposition state scheme. It shows that by increasing the harmonic order of the supercontinuum, emission efficiency increases. The detailed view shows that the short-trajectory contributes to each supercontinuous harmonic and long-trajectory fully suppresses. Finally, by superposing some properly selected harmonics from optimal spectrum, an intense and almost transform-limited isolated 38-as pulse can be generated without phase compensation. A single isolated 5-as pulse can be achieved after phase compensation. These results are explained by using classical and quantum time-frequency analyses. 相似文献
16.
The molecular dynamics process is investigated in this paper using a broadband fs time-resolved coherent anti-Stokes Raman spectroscopy (CARS) technique. By varying the timing of laser pulses, low vibrational states are started and studied on both the electronically excited B(3Π0u+) state and ground X(1Σ0g+) state of iodine in the gas phase at room temperature. According to change the pump wavelength or Stokes pulse as well as the wavelength of the detection window for the CARS signal, dynamics on different potential-energy surfaces can be accessed and detected by the CARS spectroscopy. Results show that the period of the oscillation is decreased for the excited B(3Π0u+) state as the wavelength of the pump pulses is increased, while it is increased for the ground X(1Σ0g+) state with the increase of the Stokes wavelength. 相似文献
17.
We present a comparison of quantum and “semiclassical” trajectories of coherent states that correspond to classical breather solutions of finite discrete nonlinear Schrödinger (DNLS) lattices. The main goal is to explain earlier numerical observations of recurrent return to the vicinity of initial coherent states corresponding to stable breathers that are also spatially localized. This effect can be considered as a quantum manifestation of classical spatial localization. We show that these phenomena are encoded in a simple expression for the distance between the quantum and semiclassical states that involves the basic frequencies of the classical and quantum systems, as well as the breather amplitude and quantum spectral decomposition of the system. A corollary is that recurrence phenomena are robust under perturbation of the initial conditions for stable breathers. 相似文献
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Pulse trains of fundamental soliton pulses with different center wavelengths and delay times from a photonic crystal fiber were generated and used as Stokes optical pulses in coherent anti-Stokes Raman scattering (CARS) spectroscopy. The pulse trains were created by shaping optical pulses with a pulse shaper and their waveforms were measured by a cross-correlation frequency-resolved optical gating method. By the use of pulse trains, the time required for obtaining broadband CARS signals was reduced to be about one third compared with our previous study without using pulse trains. With this setup, broadband CARS signals between 500 and 3100 cm−1 of a single polystyrene bead sample have been measured and the most of the Raman peaks in this frequency range of samples have been observed clearly. 相似文献