Harmonic mixing in two coupled qubits: Quantum synchronization via ac drives

Transport by bi-harmonic drives: from harmonic to vibrational mixing.

Transport in a one-dimensional symmetric device can be activated by the combination of thermal noise and a bi-harmonic drive. The results of extensive simulations allow us to distinguish between two apparently different bi-harmonic regimes: (i) harmonic mixing, where the two drive frequencies are commensurate but not too high; (ii) vibrational mixing, where one harmonic drive component possesse...

Quantum rectifiers from harmonic mixing

– We investigate dissipative quantum transport in extended periodic systems that are subjected to electric harmonic mixing fields Ehm(t) = E1 cos(Ωt)+E2 cos(2Ωt+φ). Although such a drive possesses no net bias on average, the interplay of quantum dissipation and nonlinear response causes a finite directed current. We thus discover the paradigm of a dissipative quantum rectifier. The quantum curr...

Scalable quantum computation via local control of only two qubits

Daniel Burgarth,1,2 Koji Maruyama,2 Michael Murphy,3 Simone Montangero,3 Tommaso Calarco,3,4 Franco Nori,2,5 and Martin B. Plenio1,6 1IMS and QOLS, Imperial College, London SW7 2PG, United Kingdom 2Advanced Science Institute, The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-0198, Japan 3Institut für Quanteninformationsverarbeitung, Universität Ulm, D-89069 Ulm, Ger...

Coherent Coupled Qubits for Quantum Annealing

Coupled qubits as a quantum heat switch

We present a quantum heat switch based on coupled superconducting qubits, connected to two LC resonators that are terminated by resistors providing two heat baths. To describe the system we use a standard second order master equation with respect to coupling to the baths. We find that this system can act as an efficient heat switch controlled by the applied magnetic flux. The flux influences th...