Shaped Josephson junction qubits

US6627915B1 · kind B1 · utility

Assignee

• D-WAVE SYSTEMS INC. · CA

Inventors

• Alexey V. Ustinov · Effeltrich, DE
• Andreas Walraff · Erlangen, DE
• Yu Koval · Erlangen, DE

Key dates

• Filing date: Aug 11, 2000
• Grant date: Sep 30, 2003
• Expiry date: Oct 27, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S977/933
• WIPO field: Micro-structural and nano-technology
• WIPO sector: Chemistry

Abstract

A superconducting qubit is presented. The qubit is a shaped long Josephson junction with a magnetic fluxon such that, in the presence of an externally applied magnetic field, a fluxon potential energy function indicating a plurality of pinning sites in the qubit is produced. In one embodiment, a heart-shaped Josephson junction is formed where a trapped fluxon has a double-welled potential energy function, indicating two pinning sites, when the junction is placed in an externally applied magnetic field. The qubit is manipulated by preparing an initial state, creating a superposition of the two states by decreasing the magnetic field, evolving of the quantum state with time, freezing in a final state by increasing the magnetic field, and reading out the final state. In other embodiments, qubit exhibiting potential energy functions having any number of pinning sites can be realized.