Quiet SDS Josephson Junctions for Quantum Computing

TL;DR

This paper discusses the development of 'quiet' Josephson junctions using unconventional superconductors, specifically d-wave cuprates, to create a solid-state qubit that is highly isolated from environmental noise for quantum computing.

Contribution

It introduces a novel 'quiet' qubit design based on degenerate ground states of d-wave/s-wave Josephson junctions, enhancing qubit stability.

Findings

Demonstration of degenerate ground states in d-wave/s-wave junctions

Construction of a 'quiet' qubit with improved environmental isolation

Potential for scalable quantum computing architectures

Abstract

Unconventional superconductors exhibit an order parameter symmetry lower than the symmetry of the underlying crystal lattice. Recent phase sensitive experiments on YBCO single crystals have established the d-wave nature of the cuprate materials, thus identifying unambiguously the first unconventional superconductor. The sign change in the order parameter can be exploited to construct a new type of s-wave - d-wave - s-wave Josephson junction exhibiting a degenerate ground state and a double-periodic current-phase characteristic. Here we discuss how to make use of these special junction characteristics in the construction of a quantum computer. Combining such junctions together with a usual s-wave link into a SQUID loop we obtain what we call a `quiet' qubit --- a solid state implementation of a quantum bit which remains optimally isolated from its environment.