Experimental Communication Through Superposition of Quantum Channels

Abstract

Information capacity enhancement through the coherent control of channels has attracted much attention of late, with work exploring the effect of coherent control of channel causal orders, channel superpositions, and information encoding. Coherently controlling channels necessitates a non-trivial expansion of the channel description, which for superposing qubit channels, is equivalent to expanding the channel to act on qutrits. Here we explore the nature of this capacity enhancement for the superposition of channels by comparing the maximum coherent information through depolarizing qubit channels and relevant superposed and qutrit channels. We show that the expanded qutrit channel description in itself is sufficient to explain the capacity enhancement without any use of superposition.

Do qubits dream of entangled sheep? Quantum measurement without classical output

“…Quantum states generated by one computer could then be used to make decisions about which circuit to encode on other computers. While, most circuits are realized presently with classical control parameters, quantum controls have been used to run superpositions of circuits [36][37][38]. Quantum computers communicating in this way would have entangled circuits and classical results would only appear when these computers interact with us 9 .…”