Linear-Optics Realization of Channels for Single-Photon Multimode Qudits

Abstract

We propose and theoretically study a method for the stochastic realization of arbitrary quantum channels on multimode single-photon qudits. In order for our method to be undemanding in its implementation, we restrict our analysis to linear-optical techniques, vacuum ancillary states and non-adaptive schemes, but we allow for random switching between different optical networks. With our method it is possible to deterministically implement random-unitary channels and to stochasti-cally implement general, non-unital channels. We provide an expression for the optimal probability of success of our scheme and calculate this quantity for specific examples like the qubit amplitude-damping channel. The success probability is shown to be related to the entanglement properties of the Choi-Jamio lkowski state isomorphic to the channel.

Error thresholds for Abelian quantum double models: Increasing the bit-flip stability of topological quantum memory

“…The latter, on the other hand, is robust against noise due to the inherent topological protection; however, it shows little prospect of scalability. Several of the current approaches to physically represent quantum information can be extended to more than two levels, including optical systems [12,13], superconductors and flux qubits [14], as well as atomic spins [15,16]. Given the theoretical promise that qudit-based systems have shown [5][6][7], it is thus of paramount interest to quantify their resilience to noise.…”