ar X iv : q ua nt - p h / 05 11 05 9 v 1 7 N ov 2 00 5 Phase Sensitivity of a Mach -

ar X iv : q ua nt - p h / 05 11 25 2 v 1 2 9 N ov 2 00 5 ( 1 + 1 ) dimensional Dirac equation with non Hermitian interaction

We study (1 + 1) dimensional Dirac equation with non Hermitian interactions, but real energies. In particular, we analyze the pseudoscalar and scalar interactions in detail, illustrating our observations with some examples. We also show that the relevant hidden symmetry of the Dirac equation with such an interaction is pseudo supersymmetry.

ar X iv : q ua nt - p h / 05 11 05 6 v 1 7 N ov 2 00 5 Robust implementations of Quantum Repeaters

We show how to efficiently exploit decoherence free subspaces, which are immune to collective noise, for realizing quantum repeaters with long lived quantum memories. Our setup consists of an assembly of simple modules and we show how to implement them in systems of cold, neutral atoms in arrays of dipole traps. We develop methods for realizing robust gate operations on qubits encoded in a DFS ...

ar X iv : q ua nt - p h / 04 11 17 2 v 1 2 3 N ov 2 00 4 Information and Entropy in Quantum Theory

ar X iv : q ua nt - p h / 02 11 05 7 v 1 1 1 N ov 2 00 2 Recursive Weak - and Strong Coupling Expansions in a Cosine Potential

For the Cos(2x)-Potential the coefficients of the weak-and strong coupling perturbation series of the ground state energy are constructed recur-sively. They match the well-known expansion coefficients of the Mathieu equation's characteristic values. However presently there is no physically intuitive method to extract the coefficients of the strong coupling series from those of the weak one. The...

ar X iv : q ua nt - p h / 05 08 06 7 v 1 8 A ug 2 00 5 NEW SCHEME OF QUANTUM TELEPORTATION

A new scheme for quantum teleportation is presented, in which the complete teleportation can be occurred even when an entangled state between Alice and Bob is not maximal.