We investigate the time evolution of a single spin excitation state in certain linear spin chains, as a model for quantum communication. We consider first the simplest possible spin chain, where the spin chain data (the nearest neighbour interaction strengths and the magnetic field strengths) are constant throughout the chain. The time evolution of a single spin state is determined, and this ti...

Abstract The photoproduction processes of the exotic Θ+(1540) baryon and the K∗ meson from the nucleon targets, i.e., γn → K∗−Θ+ and γp → K̄∗0Θ+, are investigated in a hadronic model. We consider K and K∗ exchanges as well as the s and u channel terms. Various spin asymmetries together with cross sections are estimated in order to study the production mechanisms and the parity of the Θ+(1540) ba...

The unconventional superconductor ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ has been the subject of enormous interest over more than two decades, but until now form its order parameter not explicitly determined. Since groundbreaking NMR experiments revealed recently that pairs are dominant spin-singlet character, attention focused on time-reversal symmetry breaking linear combinations $s$-, $d$-, a...

A new integrable spin chain of the Haldane-Shastry type is introduced. It is interpreted as the inverse-square interacting spin chain with a reflecting end. The lattice points of this model consist of the square of the zeros of the Laguerre polynomial. Using the “exchange operator formalism”, the integrals of motion for the model are explicitly constructed. Typeset using REVTEX ∗E-mail address ...

We discuss a family of operators which commute or anti-commute with the twisted transfer matrix of the six-vertex model at q being roots of unity: q = 1. The operators commute with the Hamiltonian of the XXZ spin chain under the twisted boundary conditions, and they are valid also for the inhomogeneous case. For the case of the anti-periodic boundary conditions, we show explicitly that the oper...