Josephson-phase qubit without tunneling

TL;DR

This paper demonstrates that complete one-bit quantum gates can be achieved in Josephson-phase qubits through microwave control of higher energy levels, eliminating the need for tunneling.

Contribution

It introduces a method to perform quantum gates without tunneling by coupling qubit states to a higher energy level using microwave pulses.

Findings

Complete set of one-bit gates realized without tunneling.

Proposed implementations include rf-SQUIDs and d-wave Josephson junctions.

Coherent control achieved via microwave-induced coupling.

Abstract

We show that a complete set of one-bit gates can be realized by coupling the two logical states of a phase qubit to a third level (at higher energy) using microwave pulses. Thus, one can achieve coherent control without invoking any tunneling between the qubit levels. We propose two implementations, using rf-SQUIDs and d-wave Josephson junctions.