Ge Mo-Lin

All Pure Two-Qudit Entangled States Generated via a Universal Yang--Baxter Matrix Assisted by Local Unitary Transformations

We show that all pure entangled states of two d-dimensional quantum systems (i.e., two qudits) can be generated from an initial separable state via a universal Yang–Baxter matrix if one is assisted by local unitary transformations.Entangled state is the cornerstone of quantum information theory [1] that has many successful applications in quantum information processing, such as the revolutionary one-way quantum computer [2], quantum cryptography [3], dense coding [4], teleportation [5], communication protocols and computation [6]. Consequently, the ability to generate and control quantum entangled states has become a far-reaching goal in experimental manipulation as well as theoretical investigation in recent years. In fact, a great number of experiments have been devoted to investigating the production of entangled states of photons (including the hyperentangled photon pairs) via the process of spontaneous parametric down-conversion in a nonlinear optical crystal [7][8], particularly for use in the tests of Bell inequalities.

Some properties of the η pairing eigenstate in the Hubbard model

Abstract Some properties of the η pairing eigenstate of the Hubbard model are investigated. It is shown that in the eigenstate the Hubbard model can present a Meissner effect, and the symmetry breaking of the Hubbard system is in analogy to the corresponding case of the Heisenberg ferromagnetic system. It is also found that the eigenstate is a projected state of the usual BCS-like function.

Two-Qubit Quantum Logic Gate in Molecular Magnets

We proposed a scheme to realize a controlled-NOT quantum logic gate in a dimer of exchange coupled single-molecule magnets,

Soliton atom laser with quantum state transfer property

[\textrm{Mn}_4]_2

Squeezed Number State Solutions of Generalized Two-Mode Harmonic Oscillators Model: an Algebraic Approach

. We chosen the ground state and the three low-lying excited states of a dimer in a finite longitudinal magnetic field as the quantum computing bases and introduced a pulsed transverse magnetic field with a special frequency. The pulsed transverse magnetic field induces the transitions between the quantum computing bases so as to realize a controlled-NOT quantum logic gate. The transition rates between the quantum computing bases and between the quantum computing bases and other excited states are evaluated and analyzed.We propose a scheme to realize a controlled-NOT quantum logic gate in a dimer of exchange coupled single-molecule magnets, [Mn4]2. We chosen the ground state and the three low-lying excited states of a dimer in a finite longitudinal magnetic field as the quantum computing bases and introduced a pulsed transverse magnetic field with a special frequency. The pulsed transverse magnetic field induces the transitions between the quantum computing bases so as to realize a controlled-NOT quantum logic gate. The transition rates between a pair of the four quantum computing bases and between the quantum computing bases and excited states are evaluated and analysed.

Coherent Photo-Association in Double-Well Bose-Einstein Condensates

We study the nonlinear effects in the quantum states transfer technique from photons to matter waves in the three-level case, which may provide the formation of a soliton atom laser with nonclassical atoms. The validity of quantum transfer mechanism is confirmed in the presence of the intrinsic nonlinear atomic interactions. The accompanied frequency chirp effect is shown to have no influence on the grey solitons formed by the output atom laser and the possible quantum depletion effect is also briefly discussed.

Effect of Noise on Berry's Phase for Quantum Computing

Some analytical solutions of generalized two-mode harmonic oscillators model are obtained by utilizing an algebraic diagonalization method. We find two types of eigenstates which are formulated as extended SU(1,1), SU(2) squeezed number states respectively. Some statistical properties of these states are also discussed.

Common Shift Operators of {H,L2} for N-Dimensional Harmonic Oscillator*

We investigate the quantum dynamics and statistics of an interesting system of the double-well Bose–Einstein condensates in the presence of a coherent photo-association process occurring in one of the two wells. Through the analytical solutions of a simplified model of the atom–molecule condensate, our results show the important impact of initial state preparations on the atomic coherence, especially the different squeezing behaviour for the case of photo-association via left-well atoms tunnelling from initial right-well atomic condensate, which holds the promise to be observed in the present laboratory.

SUPERCURRENT AND ITS QUANTUM STATISTICAL PROPERTIES IN MESOSCOPIC JOSEPHSON JUNCTION IN THE PRESENCE OF NONCLASSICAL LIGHT FIELDS

Based on a new type of two-level-system reservoir, we investigate the impact of dissipation on Berrys phase of a spin trapped in a periodical external field. It is found that the existence of environmental noise could lead to a decaying term in the matrix of Berrys phase as the sign of a decoherence process, which is in agreement with the result of Nazir et al. (Phys. Rev. A 65 (2002) 042303). Particularly, in comparison with a specialized case of the traditional Leggett dissipation model, we only shows the dependence of time but not temperature in decaying term. A concrete case is exhibited by using the one-dimensional Ohmic function.

An Alternative Approach to Jaynes–Cummings Model with Dissipation at Finite Temperature*

The common shift operators of {H,L2} for N-dimensional harmonic oscillator are established.