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

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 -

The best performance of a Mach-Zehnder interferometer is achieved with the input state |NT /2+ 1〉|NT /2 − 1〉 + |NT /2 − 1〉|NT /2 + 1〉, being NT the total number of atoms/photons. This gives: i) a phase-shift error confidence C68% = 2.67/NT with ii) a single interferometric measurement. Different input quantum states can achieve the Heisenberg scaling ∼ 1/NT but with higher prefactors and at the...

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 / 06 09 11 5 v 1 1 5 Se p 20 06 Shape invariance approach to exact solutions

Using the shape invariance property we obtain exact solutions of the (1 + 1) dimensional Klein-Gordon equation for certain types of scalar and vector potentials. We also discuss the possibility of obtaining real energy spectrum with non-Hermitian interaction within this framework.

ar X iv : q ua nt - p h / 05 05 22 1 v 1 3 0 M ay 2 00 5 PT symmetric models with nonlinear pseudo supersymmetry

By applying the higher order Darboux algorithm to an exactly solvable non Hermitian PT symmetric potential, we obtain a hierarchy of new exactly solvable non Hermitian PT symmetric potentials with real spectra. It is shown that the symmetry underlying the potentials so generated and the original one is nonlinear pseudo supersymmetry. We also show that this formalism can be used to generate a la...

ar X iv : q ua nt - p h / 02 05 05 2 v 1 1 0 M ay 2 00 2 ALTERNATIVE STRUCTURES AND BIHAMILTONIAN SYSTEMS

In the study of bi-Hamiltonian systems (both classical and quantum) one starts with a given dynamics and looks for all alternative Hamiltonian descriptions it admits. In this paper we start with two compatible Hermitian structures (the quantum analog of two compatible classical Poisson brackets) and look for all the dynamical systems which turn out to be bi-Hamiltonian with respect to them.