Operation of a quantum processor unit demands very sophisticated peripherals, circuitry and control/readout electronics. We work in the design and fabrication of Josephson-based quantum circuits for different purposes.
On the one hand, we develop tuneable coherent couplers between multiplexable lumped LC resonators. The latter serve to entangle or to transfer quantum states between different components of the quantum processor as, e.g., qubits and a quantum RAM memory. On the other hand, we are interested on the fabrication of quantum-limited Josephson parametric amplifiers for qubit readout.
Our amplifiers consist on a capacitor and a non-linear Josephson-based inductor connected in parallel. These devices are based on the transfer of energy between a pumping tone and the readout signal, similarly to the effect of optic parametric amplification in nonlinear crystals.
In QMAD we are experts in very low temperature physics and cryogenic methods. We have access to two cryogen-free dilution refrigerators and several 4 K-cryostates for testing purposes. We design and fabricate our own mw printed circuit boards and PCB packing. We are also experts in nanofabrication of superconducting and Josephson circuitry.