Isospin dependence of pseudospin symmetry in nuclear resonant states

The relativistic mean field theory in combination with the analytic continuation in the coupling constant method is used to determine the energies and widths of single-particle resonant states in Sn isotopes. It is shown that there exists clear shell structure in the resonant levels as appearing in the bound levels. In particular, the isospin dependence of pseudospin symmetry is clearly shown in the resonant states, is consistent with that in the bound states, where the splittings of energies and widths between pseudospin doublets are found in correlation with the quantum numbers of single-particle states, as well as the nuclear mass number. The similar phenomenon also emerges in the spin partners.Comment: 7 pages, 6 figure

Local Operations in qubit arrays via global but periodic Manipulation

We provide a scheme for quantum computation in lattice systems via global but periodic manipulation, in which only effective periodic magnetic fields and global nearest neighbor interaction are required. All operations in our scheme are attainable in optical lattice or solid state systems. We also investigate universal quantum operations and quantum simulation in 2 dimensional lattice. We find global manipulations are superior in simulating some nontrivial many body Hamiltonians.Comment: 5 pages, 2 figures, to appear in Phys. Rev.

Stability of Pairwise Entanglement in a Decoherent Environment

Consider the dynamics of a two-qubit entangled system in the decoherence environment, we investigate the stability of pairwise entanglement under decoherence. We find that for different decoherence models, there exist some special class of entangled states of which the pairwise entanglement is the most stable. The lifetime of the entanglement in these states is larger than other states with the same initial entanglement. In addition, we also investigate the dynamics of pairwise entanglement in the ground state of spin models such as Heisenberg and XXY models.Comment: accepted by Physical Review A, references updated and minor change

New molecular candidates: X(1910), X(2200), and X(2350)

Assuming the newly observed resonant structures X(1910), X(2200), and X(2350) as $\omega\omega$, $\omega\phi$, and $\phi\phi$ molecular states respectively, we compute their mass values in the framework of QCD sum rules. The numerical results are $1.97\pm0.17 {GeV}$ for $\omega\omega$ state, $2.07\pm0.21 {GeV}$ for $\omega\phi$ state, and $2.18\pm0.29 {GeV}$ for $\phi\phi$ state, which coincide with the experimental values of X(1910), X(2200), and X(2350), respectively. This supports the statement that X(1910), X(2200), and X(2350) could be $\omega\omega$, $\omega\phi$, and $\phi\phi$ molecular candidates respectively.Comment: 9 pages, 9 eps figures; the name of X(2000) changed to X(1910) according to the updated data of experiments; more references and discussions added; accepted for publication in PRD. arXiv admin note: substantial text overlap with arXiv:1211.2277, arXiv:1201.341

Low Frequency Quantum Transport in a Three-probe Mesoscopic Conductor

The low frequency quantum transport properties of a three-probe mesoscopic conductor are studied using B\"uttiker's AC transport formalism. The static transmission coefficients and emittance matrix of the system were computed by explicitly evaluating the various partial density of states (PDOS). We have investigated the finite size effect of the scattering volume on the global PDOS. By increasing the scattering volume we observed a gradual improvement in the agreement of the total DOS as computed externally or locally. Our numerical data permits a particular fitting form of the finite size effect.Comment: 13 pages, LaTeX, submitted to Phys. Rev.

Realization of All-or-nothing-type Kochen-Specker Experiment with Single Photons

Using the spontaneous parametric down-conversion process in a type-I phase matching BBO crystal as single photon source, we perform an all-or-nothing-type Kochen-Specker experiment proposed by Simon \QTR{it}{et al}. [Phys. Rev. Lett. \QTR{bf}{85}, 1783 (2000)] to verify whether noncontextual hidden variables or quantum mechanics is right. The results strongly agree with quantum mechanics.Comment: 3 figure

Weakly nonlinear quantum transport: an exactly solvable model

We have studied the weakly non-linear quantum transport properties of a two-dimensional quantum wire which can be solved exactly. The non-linear transport coefficients have been calculated and interesting physical properties revealed. In particular we found that as the incoming electron energy approaches a resonant point given by energy $E=E_r$, where the transport is characterized by a complete reflection, the second order non-linear conductance changes its sign. This has interesting implications to the current-voltage characteristics. We have also investigated the establishment of the gauge invariance condition. We found that for systems with a finite scattering region, correction terms to the theoretical formalism are needed to preserve the gauge invariance. These corrections were derived analytically for this model.Comment: 15 pages, LaTeX, submitted to Phys. Rev.