共查询到20条相似文献,搜索用时 171 毫秒
1.
We propose a scheme to implement the Deutsch-Jozsa algorithm by using Schroedinger cat states in cavity quantum electron-dynamics (QED). The scheme is based on the Raman interaction of a degenerate three-level A-type atom with a coherent state in a cavity. By using Schroedinger cat states, the atomic spontaneous emission can be minimized and the Hadamard transformation in our scheme is not needed. 相似文献
2.
利用一个参量频率转换过程,在腔中制备双模SU(2)相干态,然后注入一个与腔场的一个个模发生拉曼相互作用的A型三能级原子,通过原子-腔场相互作用生成腔场-原子纠缠,通过对原子进行选择性测量,腔场-原子纠缠态将塌缩到纯态,即双模SU(2)薛定谔猫态。 相似文献
3.
Entropy evolvement properties in a system of Schrodinger cat state light field interacting with two entangled atoms 下载免费PDF全文
The field entropy can be regarded as a measurement of the degree of
entanglement between the light field and the atoms of a system which is
composed of two-level atoms initially in an entangled state interacting with the Schr\"{o}dinger cat state. The influences of the strength of light field and the phase angle between the two coherent states on the field entropy are discussed by using numerical calculations. The result shows that when the strength of light field is large enough the field entropy is not zero and the degrees of entanglement between the atoms and the three different states of the light fields are equal. When the strength of the light field is small, the degree of entanglement is maximum in a system of the two entangled atoms interacting with an odd coherent state; it is intermediate for a system of the two entangled atoms interacting with the Yurke--Stoler coherent state, and it is minimum in a system of the two entangled atoms interacting with an even coherent state. 相似文献
4.
Based on the exact solution of the time-dependent Schr\"{o}dinger
equation for two-species Bose--Einstein condensates (BECs)
consisting of two hyperfine states of the atoms coupled by a tuned
adiabatic and time-varying Raman coupling, we obtain analytically
the entanglement dynamics of the system with various initial
states, particularly the SU(2) coherent state, for both of
cases with and without the nonlinear interactions. It is shown
that the effect of nonlinear interaction on the entanglement
appears only in a longer time period depending on the BEC
parameters. 相似文献
5.
6.
By using the solutions of an auxiliary Lam\'e equation, a direct algebraic method is
proposed to construct the exact solutions of $N$-coupled nonlinear Schr\"{o}dinger
equations. The abundant higher-order exact periodic solutions of a family of
$N$-coupled nonlinear Schr\"{o}dinger equations are explicitly obtained with the aid
of symbolic computation and they include corresponding envelope solitary and shock
wave solutions. 相似文献
7.
Bright and dark small amplitude nonlinear localized modes in a quantum one-dimensional Klein--Gordon chain 总被引:1,自引:0,他引:1 下载免费PDF全文
By means of the Glauber's coherent state method combined with multiple-scale method, this paper investigates the localized modes in a quantum one-dimensional Klein-Gordon chain and finds that the equation of motion of annihilation operator is reduced to the nonlinear Schroedinger equation. Interestingly, the model can support both bright and dark small amplitude travelling and non-travelling nonlinear localized modes in different parameter spaces. 相似文献
8.
9.
Beyond the Lamb-Dicke limit, we propose a simple scheme for generating Schr?dinger cat states of the motion of a trapped two-level ion interacting with a quantized light field in a single-mode cavity. 相似文献
10.
P. Horak H. Ritsch 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):279-287
We propose a method to create macroscopic superpositions, so-called Schr?dinger cat states, of different motional states of
an ideal Bose-Einstein condensate. The scheme is based on the scattering of a freely expanding condensate by the light field
of a high-finesse optical cavity in a quantum superposition state of different photon numbers. The atom-photon interaction
creates an entangled state of the motional state of the condensate and the photon number, which can be converted into a pure
atomic Schr?dinger cat state by operations only acting on the cavity field. We discuss in detail the fully quantised theory
and propose an experimental procedure to implement the scheme using short coherent light pulses.
Received 26 June 2000 and Received in final form 2nd October 2000 相似文献
11.
Pseudospectral method with symplectic algorithm for the solution of time-dependent SchrSdinger equations 下载免费PDF全文
A pseudospectral method with symplectic algorithm for the solution of time-dependent Schrodinger equations (TDSE) is introduced. The spatial part of the wavefunction is discretized into sparse grid by pseudospectral method and the time evolution is given in symplectic scheme. This method allows us to obtain a highly accurate and stable solution of TDSE. The effectiveness and efficiency of this method is demonstrated by the high-order harmonic spectra of one-dimensional atom in strong laser field as compared with previously published work. The influence of the additional static electric field is also investigated. 相似文献
12.
在低Q值腔内,原子相干态在一些特定时刻可以演化为原子薛定谔猫态.讨论了在这种原子薛定谔猫态中原子角动量的涨落和高阶涨落.根据不确定性原理,进一步研究了原子角动量的压缩和高阶压缩性质及其演化.研究表明,原子薛定谔猫态可以被压缩到二阶和六阶,但不能被压缩到四阶.当原子薛定谔猫态中被叠加的原子相干态数为无限多项时,其压缩特性与原子相干态相同.
关键词:
原子相干态
薛定谔猫态
角动量压缩
Bloch态 相似文献
13.
H.-P. Breuer U. Dorner F. Petruccione 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(3):377-386
In a recent experiment the progressive decoherence of a mesoscopic superposition of two coherent field states in a high-Q cavity, known as Schr?dinger cat state, has been measured for the first time [Brune et al., Phys. Rev. Lett. 77, 4887 (1996)]. Here, the full master equation governing the coupled dissipative dynamics of the atom-field system studied
in the experiment is formulated and solved numerically for the experimental parameters. The model simulated avoids the approximations
underlying an analytically solvable model which is based on a harmonic expansion of the energies of the dressed atomic states
and on a treatment of their dynamics within the adiabatic approximation. In particular, the numerical simulations reveal that
the coupling of the cavity field mode to its environment causes important decoherence effects already during the initial preparation
phase of the Schr?dinger cat state. This phenomenon is investigated in detail with the help of a measure for the purity of
states. Moreover, the Hilbert-Schmidt distance of the intended target state, the Schr?dinger cat, to the state that is actually
prepared in the experiment is determined.
Received 13 September 2000 and Received in final form 22 December 2000 相似文献
14.
The fidelity of the generated Schrdinger Cat state(SCS) of a single trapped ion in the Lamb-Dicke approximation is discussed.The results show that the fidelity significantly decreases with the values of Lamb-Dicke parameter η and coherent state amplitude α increasing.For η = 0.20 and α = 3,the typical values of experimental parameters,the fidelity is rather low(30%).A scheme for generating the SCS is proposed without making the Lamb-Dike approximation in laser-ion interaction,and the fidelity of the generated SCS is about 99% for the typical values of experimental Lamb-Dicke parameters. 相似文献
15.
This paper presents calculating results of the two-dimensional
electron gas (2DEG) distributions in AlGaN/GaN material system by
solving the Schr\"{o}dinger and Poisson equations self-consistently.
Due to high 2DEG density in the AlGaN/GaN heterojunction interface,
the exchange correlation potential should be considered among the
potential energy item of Schr\"{o}dinger equation. Analysis of the
exchange correlation potential is given. The dependencies of the
conduction band edge, 2DEG density on the Al mole fraction are
presented. The polarization fields have strong influence on 2DEG
density in the AlGaN/GaN heterojunction, so the dependency of the
conduction band edge on the polarization is also given. 相似文献
16.
PREPARATION OF NONCLASSICAL STATES OF A CAVITY FIELD BASED ON A NONLINEAR JAYNES-CUMMINGS MODEL 下载免费PDF全文
It is proven in this paper that some kinds of nonclassical quantum states of the cavity field, such as Schr?dinger cat state (amplitude cat or phase cat), sub-Poissonian photon distribution and Fock state, etc., can be generated by conditional meas urements on atoms in the two-photon Jaynes-Cummings model with a Kerr-like medium. The nonlinear constant plays the key modulation role in the preparation of the quantum states, which gives a new controllable parameter for further experi mental researches in this field. 相似文献
17.
This paper presents calculating results of the two-dimensional electron gas (2DEG) distributions in AlGaN/GaN material system by solving the Schroedinger and Poisson equations self-consistently. Due to high 2DEG density in the AlGaN/GaN heterojunction interface, the exchange correlation potential should be considered among the potential energy item of Schroedinger equation. Analysis of the exchange correlation potential is given. The dependencies of the conduction band edge, 2DEG density on the Al mole fraction are presented. The polarization fields have strong influence on 2DEG density in the AlGaN/GaN heterojunction, so the dependency of the conduction band edge on the polarization is also given. 相似文献
18.
Potential energy curves and analytical potential energy functions of the metastable states of B2^++ 下载免费PDF全文
The multi-reference configuration interaction method and aug-cc-pvqz (AVQZ) have been used to calculate potential energy curves (PECs) of the singlet and triplet states of the riu and rig symmetry of B2++. All of the four states (^l∏u, ^1∏g, ^3∏u and ^3∏g) are found to be metastable states, though the potential well of ^3∏u symmetry is very shallow. Based on the PECs, the analytical potential energy functions (APEFs) of these states have been fitted using the least square fitting method and two models of function. The spectroscopic parameters of each state are also calculated, and are compared with other investigations in the literature. The credibility and veracity of the two functions are evaluated. Some ideas to improve the fitting accuracy are presented. Also the vibrational levels for each state are predicted by solving the SchrSdinger equation of nuclear motion. 相似文献
19.
ZHENGShi-Biao LINLi-Hua JIANGYun-Kun 《理论物理通讯》2003,40(1):103-104
An efficient scheme is proposed for the generation of atomic Schroedinger cat states in an optical cavity. In the scheme N three-level atoms are loaded in the optical cavity. Raman coupling of two ground states is achieved via a laser tield and the cavity mode. The cavity mode is always in the vacuum state and the atoms have no probability of being populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and spontaneous emission. 相似文献
20.
We investigate the one-dimensional
nonlinear Schrödinger equation with a perturbation of polynomial
type. The approximate symmetries and approximate symmetry reduction
equations are obtained with the approximate symmetry perturbation
theory. 相似文献