共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
The nonadiabatic geometric phase(AA phase) generating in the quantum system consisting of a single-mode or many-mode cavity field with a quantized oscillating-mirror has been discussed. The result shows that such a phase only depends on the intensity of the cavity field but not on its photon statistics, which contrasts to these occuring in a Kerr-like medium. 相似文献
3.
We elaborate on the distinction between geometric and dynamical phase in quantum theory and we show that the former is intrinsically linked to the quantum mechanical probabilistic structure. In particular, we examine the appearance of the Berry phase in the consistent histories scheme and establish that it is the basic building block of the decoherence functional. These results are consequences of the novel temporal structure of histories-based theories. 相似文献
4.
Wenyi Shao Yangyang Du Qi Yang Gangcheng Wang Chunfang Sun Kang Xue 《International Journal of Theoretical Physics》2017,56(3):643-651
In this paper, we construct a parameterized form of unitary \(\breve {R}_{123}(\theta _{1},\theta _{2},\varphi )\) matrix through the Yang-Baxterization method. Acting such matrix on three-qubit natural basis as a quantum gate, we can obtain a set of entangled states, which possess the same entanglement value depending on the parameters ?? 1 and ?? 2. Particularly, such entangled states can produce a set of maximally entangled bases Greenberger-Horne-Zeilinger (GHZ) states with respect to ?? 1 = ?? 2 = π/2. Choosing a useful Hamiltonian, one can study the evolution of the eigenstates and investigate the result of Berry phase. It is not difficult to find that the Berry phase for this new three-qubit system consistent with the solid angle on the Bloch sphere. 相似文献
5.
JETP Letters - We consider the high-frequency conductance of a two-state quantum system within non-equilibrium Green’s function formalism. Multiply connected configurations possessing... 相似文献
6.
R. Resta 《Europhysics News》1997,28(1):18-20
The macroscopic polarization of a crystalline dielectric is best defined as a Berry phase of the electronic Bloch wavefunctions, a feature that is best exemplified by the spontaneous polarization of a ferroelectric crystal for which a microscopic theory was previously unavailable. 相似文献
7.
In this paper, we consider the interaction between the two-level atom and the electromagnetic field modes initially prepared in coherent states associated with the generalized Heisenberg algebra (GHA). We investigate the dynamical behavior of the field purity, Pancharatnam phase, and atomic-population inversion. Based on the GHA, we study the statistical properties of the field state through the evolution of the Mandel parameter and examine the effects of the initial atomic state setting and the number of transiting photons. The results show that the GHA-coherent-state strength has the potential to affect the time evolution of the field purification, the Pancharatnam phase, and the Mandel parameter. 相似文献
8.
1IntroductionThegeometricphaseplaysanimportantroleinunderstandingsomeoftheoutstandingenigmasofquantummechanics,andithaspaidmu... 相似文献
9.
We present a new general and much simpler scheme to construct various quantum phase transitions (Q, PTs) in spin chain systems with matrix product ground states. By use of the scheme we take into account one kind of matrix product state (MPS) OPT and provide a concrete model. We also study the properties of the concrete example and show that a kind of Q, PT appears, accompanied by the appearance of the discontinuity of the parity absent block physical observable, diverging correlation length only for the parity absent block operator, and other properties which are that the fixed point of the transition point is an isolated intermediate-coupling fixed point of renormalization flow and the entanglement entropy of a half-infinite chain is discontinuous. 相似文献
10.
An intrinsically stable quantum key distribution system (QKD) with six polarization states encoded by phase modulation is introduced. The encoder and decoder are in the same structures that consist of two polarizing Sagnac interferometers connected in tandem. The six polarization states are determined and distinguished by different sets of phase shifts induced by two respective electrically-driven integrated phase modulators. A mean visibility of interference fringes is kept stable at 97.58% for an hour's performance. Theoretical and experimental analyses show that the proposed QKD system features intrinsically stability immune from environment fluctuation. 相似文献
11.
Z. S. Wang 《International Journal of Theoretical Physics》2012,51(11):3647-3654
By seeking for a useful generic solution of Lindblad master equation, we find that the density matrix of mixed state carries with the geometric messages, where the density matrix of mixed state is expanded in terms of a complete set of normalized, traceless and Hermitian matrices together with a unit matrix in a Hilbert space. Our approach to the geometric phases of mixed state are directly from the master equation describing a dynamic evolution of open system and therefore may be conceptually useful in analyzing the geometric phases of mixed state. An example is discussed for the nuclear-magnetic-resonance system interacting with its surrounding environment. 相似文献
12.
Fine control of the dynamics of a quantum system is the key element to perform quantum information processing and coherent manipulations for atomic and molecular systems. We propose a control protocol using a tangentpulse driven model and demonstrate that it indicates a desirable design, i.e., of being both fast and accurate for population transfer. As opposed to other existing strategies, a remarkable character of the present scheme is that high velocity of the nonadiabatic evolution itself not only will not lead to unwanted transitions but also can suppress the error caused by the truncation of the driving pulse. 相似文献
13.
Nonlocal decoherence of two qubits due to pure phase damping has been investigated. We have proposed a scheme to keep the entanglement of two qubits from nonlocal decoherence. By applying a series of ±π pulses, nonlocal decoherence can be thoroughly suppressed. 相似文献
14.
The Berry phase in a composite system induced by the time-dependent interaction is discussed. We choose two coupled spin-1/2 systems as the composite system: one of the subsystems is subjected to a static magnetic field, and the coupling parameters between two spins are controllable in time. We show that the time-dependent interaction can induce the Berry phase in a similar way as that a spin-1/2 system (qubit) is driven by an effective time-dependent magnetic field. Furthermore, using two consecutive cycles with opposite directions of both the static magnetic field as well as opposite signs of the coupling parameters, a nontrivial two-qubit unitary transformation purely based on Berry phases can be constructed. 相似文献
15.
In this paper we have considered closed trajectories of a particle on a two-torus where the loops are noncontractible (poloidal and toroidal loops and knots embedded on a regular torus). We have calculated Hannay angle and Berry phase for particle traversing such loops and knots when the torus itself is adiabatically revolving. Since noncontractible loops do not enclose any area Stokes theorem has to be applied with caution. In our computational scheme we have worked with line integrals directly thus avoiding Stokes theorem.
相似文献16.
Nonlocal decoherence of two qubits due to Pure phase damping has been investigated. We have proposed a scheme to keep the entanglement of two qubits from nonlocal decoherence. By applying a series of ±π pulses, nonlocal decoherence can be thoroughly suppressed. 相似文献
17.
18.
WANGZhong-Jie 《理论物理通讯》2004,42(4):539-542
Dynamical control of decoherence induced by the environment in a single quantum-bit system is investigated. We choose the suitable perturbations acting on the qubit system to decrease the decoherence due to pure amplitude damping. The scheme proposed here is based on the free-Hamiltonian-elimination technique and the paritykick technique, which concludes two homogeneous classical large-blue-detuned optical fields with different frequencies added to the qubit system. By applying this scheme, the decoherence can be completely suppressed. 相似文献
19.
We prove the existence of a phase transition in the quantum Widom–Rowlison model in two dimension. The case of Boltzmann and Bose statistics are explicitly discussed. 相似文献
20.
Pierpaolo Mastrolia 《Letters in Mathematical Physics》2010,91(2):199-204
Elaborating on the observation that two-particle unitarity-cuts of scattering amplitudes can be computed by applying Stokes’
theorem, we relate the optical theorem to the Berry phase, showing how the imaginary part of arbitrary one-loop Feynman amplitudes
can be interpreted as the flux of a complex 2-form. 相似文献