Autonomous Quantum State Transfer By Dissipation Engineering

Quantum state transfer from an information-carrying qubit to a receiving qubit is ubiquitous for quantum information technology. In a closed quantum system, this task requires precisely timed control of coherent qubit-qubit interactions that are intrinsically reciprocal. Here, breaking reciprocity by tailoring dissipation in an open system, we show that it is possible to transfer a quantum state between stationary qubits autonomously without time-dependent control. We present the general requirements for this directional transfer process and show that the minimum system dimension for transferring one qubit of information is 3 x 2 (between one physical qutrit and one physical qubit) plus one auxiliary reservoir. We propose realistic implementations in present-day superconducting circuit QED experiments and further propose schemes compatible with long-distance state transfer using impedance-matched dissipation engineering.