Multi-qubit tunable coupling architecture using fixed-frequency superconducting qubits

摘要

A coupling mechanism, method of activation and a square lattice. The coupling mechanism comprises two qubits (102,104) and a tunable coupling qubit (106) that activates an interaction between the two qubits (102,104) by modulation of a frequency of the tunable coupling qubit (106). The tunable coupling qubit (106) capacitively couples the two qubits (102,104). The tunable coupling qubit (106) is modulated at a difference frequency of the two qubits (102,104). The difference frequency may be significantly larger than an anharmonicity of the two qubits (102,104). The tunable coupling qubit (106) may be coupled to the two qubits (102,104) by two electrodes separated by a superconducting quantum interference device (SQUID) loop having two Josephson junctions or by a single electrode with a SQUID loop coupling to ground. The SQUID loop is controlled by an inductively-coupled flux bias line positioned at the center of the tunable coupling qubit.