A single photon produces general W state of N qubits and its application

Based on the Wu's scheme[1], We prepare the general N-qubit W state. We find that the concurrence of two qubits in general N-qubit W state is only related to their coefficients and we successfully apply the general N-qubit W state to quantum state transfer and quantum state prepare like that in two-qubit system

Maximal Entanglement of Two-qubit States Constructed by Linearly Independent Coherent States

In this paper, we find the necessary and sufficient condition for the maximal entanglement of the state, $|\psi>=\mu|\alpha>|\beta>+\lambda|\alpha>|\delta>+ \rho|\gamma>|\beta>+\nu|\gamma>|\delta>,$ constructed by linearly independent coherent states with \emph{real parameters} when $=$. This is a further generalization of the classified nonorthogonal states discussed in Ref. Physics Letters A {\bf{291}}, 73-76 (2001).Comment: some examples added; Int J Theor Phys 201

Entanglement in bipartite generalized coherent states

Entanglement in a class of bipartite generalized coherent states is discussed. It is shown that a positive parameter can be associated with the bipartite generalized coherent states so that the states with equal value for the parameter are of equal entanglement. It is shown that the maximum possible entanglement of 1 bit is attained if the positive parameter equals $\sqrt{2}$. The result that the entanglement is one bit when the relative phase between the composing states is $\pi$ in bipartite coherent states is shown to be true for the class of bipartite generalized coherent states considered.Comment: 10 pages, 4 figures; typos corrected and figures redrawn for better clarit

ON THE INTRINSIC CHARM COMPONENT OF THE NUCLEON

Using a $\overline D$ meson cloud model we calculate the squared charm radius of the nucleon . The ratio between this squared radius and the ordinary baryon squared radius is identified with the probability of ``seeing'' the intrinsic charm component of the nucleon. Our estimate is compatible with those used to successfully describe the charm production phenomenology.Comment: 9 pages, 2 figures not included, avaiable from the author

Quantum teleportation of light beams

We experimentally demonstrate quantum teleportation for continuous variables using squeezed-state entanglement. The teleportation fidelity for a real experimental system is calculated explicitly, including relevant imperfection factors such as propagation losses, detection inefficiencies and phase fluctuations. The inferred fidelity for input coherent states is F = 0.61 +- 0.02, which when corrected for the efficiency of detection by the output observer, gives a fidelity of 0.62. By contrast, the projected result based on the independently measured entanglement and efficiencies is 0.69. The teleportation protocol is explained in detail, including a discussion of discrepancy between experiment and theory, as well as of the limitations of the current apparatus.Comment: 17 pages, 19 figures, submitted to PR

Wilson Fermions on a Transverse Lattice

In the light-front formulation of field theory, it is possible to write down a chirally invariant mass term. It thus appears as if one could solve the species doubling problem on a light-front quantized transverse lattice in a chirally invariant way. However, upon introducing link fields and after renormalizing, one finds exactly the same LF Hamiltonian as if one had started from the standard Wilson action in the first place. The (light-front) chirally invariant transverse lattice regularization is thus not chirally invariant in the conventional sense. As an application of the Wilson formulation for fermions on a $\perp$ lattice, we calculate spectrum, distribution functions and distribution amplitudes for mesons below $2 GeV$ in a truncated Fock space.Comment: 14 pages, RevTe

Improved results for N=(2,2) super Yang-Mills theory using supersymmetric discrete light-cone quantization

We consider the (1+1)-dimensional ${\cal N}=(2,2)$ super Yang--Mills theory which is obtained by dimensionally reducing ${\cal N}=1$ super Yang--Mills theory in four dimension to two dimensions. We do our calculations in the large-$N_c$ approximation using Supersymmetric Discrete Light Cone Quantization. The objective is to calculate quantities that might be investigated by researchers using other numerical methods. We present a precision study of the low-mass spectrum and the stress-energy correlator $$. We find that the mass gap of this theory closes as the numerical resolution goes to infinity and that the correlator in the intermediate $r$ region behaves like $r^{-4.75}$.Comment: 18 pages, 8 figure