Quantum decoherence without damping

Nima Arkani-hamed A, John E. Sipe

Min-Zhe Piao, Xin Ji

We investigate the quantum decoherence of Dirac fields in a non-inertial system under phase damping channel. The quantum decoherence and the loss of entanglement generated by Unruh radiation will influence each other, and the entanglement disappears only as time tends to infinity whether one or two qubits of system is coupled to the environment.

Heinz‐Peter Breuer, Francesco Petruccione

Piotr Marecki

Julius Helm, Walter T. Strunz

It is commonly stated that decoherence in open quantum systems is due to growing entanglement with an environment. In practice, however, surprisingly often decoherence may equally well be described by random unitary dynamics without invoking a quantum environment at all. For a single qubit, for instance, pure decoherence (or phase damping) is always of random unitary type. Here, we construct a simple example of true quantum decoherence of two qubits: we present a feasible phase damping channel of which we show that it cannot be understood in terms of random unitary dynamics. We give a very intuitive geometrical measure for the positive distance of our channel to the convex set of random unitary channels and find remarkable agreement with the so-called Birkhoff defect based on the norm of complete boundedness.