Decoherence-free subspaceにおける量子ゲートについて

Alireza Shabani, Daniel A. Lidar

G. D. M. Neto, A. Cacheffo, Antonio S. M. de Castro +2 more

We present a technique to build, within a dissipative bosonic network, decoherence-free channels (DFCs): a group of normal-mode oscillators with null effective damping rates. We verify that the states protected within the DFC define the well-known decoherence-free subspaces (DFSs) when mapped back into the natural network oscillators. Therefore, our technique to build protected normal-mode channels turns out to be an alternative way to build DFSs, which offers advantages over the conventional method. It enables the computation of all the network-protected states at once, as well as leading naturally to the concept of the decoherence quasi-free subspace (DQFS), inside which a superposition state is quasi-completely protected against decoherence. The concept of the DQFS, weaker than that of the DFS, may provide a more manageable mechanism to control decoherence. Finally, as an application of the DQFSs, we show how to build them for quasi-perfect state transfer in networks of coupled quantum dissipative oscillators.

Daniel A. Lidar, K. Birgitta Whaley

Purva Thakre, Mark Byrd

Yu Pan, Daoyi Dong, Ian R. Petersen

A decoherence-free mode lies at the heart of the preservation of quantum information against external noise. In this paper we propose a direct method for the analysis and synthesis of a decoherence-free mode in quantum linear systems. First, we derive a necessary condition for the existence of a decoherence-free mode. Then, the synthesis of the decoherence-free mode via Hamiltonian control is discussed.

剛史 林, 敏彦 有光