Tunable Superconducting Flux Qubits with Long Coherence Times

Tunable coupling of superconducting qubits.

We study an LC circuit implemented using a current-biased Josephson junction (CBJJ) as a tunable coupler for superconducting qubits. By modulating the bias current, the junction can be tuned in and out of resonance and entangled with the qubits coupled to it. One can thus implement two-qubit operations by mediating entanglement. We consider the examples of CBJJ and charge-phase qubits. A simple...

Long coherence times for Rydberg qubits on a superconducting atom chip

Long-range coupling and scalable architecture for superconducting flux qubits

Austin G. Fowler,1 William F. Thompson,1 Zhizhong Yan,1 Ashley M. Stephens,2 B. L. T. Plourde,3 and Frank K. Wilhelm1 1Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 2Centre for Quantum Computer Technology, University of Melbourne, Victoria 3010, Australia 3Department of Physics, Syracuse University, Syracuse, New York 13244, USA !Received 20 April 20...

Long-range and selective coupler for superconducting flux qubits

We propose a qubit-qubit coupling scheme for superconducting flux quantum bits (qubits), where a quantized Josephson junction resonator and microwave irradiation are utilized. The junction is used as a tunable inductance controlled by changing the bias current flowing through the junction, and thus the circuit works as a tunable resonator. This enables us to make any qubits interact with the re...

Fast tunable coupler for superconducting qubits.

A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tunable coupling circuit that allows superconducting qubits to be coupled over long distances. We show that the interqubit coupling strength can be arbitrarily tuned over nanosecond time scales within a sequence that mimics actual use in an algorithm. Th...