Non-Hermitian description of a superconducting phase qubit measurement

We present an approach based on a non-Hermitian Hamiltonian to describe the process of measurement by tunneling of superconducting phase qubit states. We derive simple analytical expressions which describe the dynamics of measurement, and compare our results with those experimentally available. In particular, we show that even for a single qubit, the analytical expressions simplify the analysis of the dynamics in comparison with the density matrix approach. We also demonstrate that the effect of the interference of tunneling channels can be easily described by using the approach based on the non-Hermitian Hamiltonian. © 2010 World Scientific Publishing Company