Decoherence Caused by Topology in a Time-Machine Spacetime

Masahito Ueda

Pei-Hua Liu, Feng-Li Lin

In this paper, we consider the decoherence patterns of a topological qubit made of two Majorana zero modes in the generic linear and circular motions in the Minkowski spacetime. We show that the reduced dynamics is exact without Markov approximation. Our results imply that the acceleration will cause thermalization as expected by Unruh effect. However, for the short-time scale, we find the rate of decoherence is anti-correlated with the acceleration, as kind of decoherence impedance. This is in fact related to the “anti-Unruh” phenomenon previously found by studying the transition probability of Unruh-DeWitt detector. We also obtain the information backflow by some time modulations of coupling constant or acceleration, which is a characteristic of the underlying non-Markovian reduced dynamics. Moreover, by exploiting the nonlocal nature of the topological qubit, we find that some incoherent accelerations of the constituent Majorana zero modes can preserve the coherence instead of thermalizing it.

Magdalena Zych

Hiroaki Terashima, Masahito Ueda

A mechanism of spin decoherence caused by spacetime curvature in general relativity is discussed. The spin state of a particle is shown to decohere only if the particle moves in a curved spacetime. In particular, when a particle is near the event horizon of a black hole, an extremely rapid spin decoherence occurs for an observer who is static in a Killing time, however slow the particle's motion.

J. J. Halliwell

J. J. Halliwell