Bloch transistor for cryogenic quantum electronics

We report on observation of two coherent quantum phenomena, the current quantization in the Josephson Junction (JJ) and the Aharonov-Cashier effect. The synergy of two effects is seen as the phase locking of the JJ with the oscillating charge engaged by the microwaves (the current quantization), and a control of the phase locking phenomenon with the static charge of the gate electrode (the Aharonov-Cashier effect). The experimental system consists of two coupled JJs in the regime of coherent quantum phase slip. When the microwave is applied, the quantized current plateaus appear on the I - V curve. The effect is dual to the Shapiro voltage steps in JJs. We modulate the quantized current with the static charge induced by the gate electrode. Conceptually, the system has the functionality of the Bloch Transistor: it can deliver gate-controlled quantized non-dissipative current to the quantum circuit.