Memory cell based on a $\varphi$ Josephson junction

TL;DR

This paper demonstrates a novel memory cell based on a doubly degenerate $$ Josephson junction, enabling stable data storage and easy integration with existing quantum logic systems.

Contribution

It introduces a $$ Josephson junction as a new type of classical memory cell with stable storage and simple read/write operations.

Findings

Memory cell maintains state without bias or magnetic field after cooling

Writing is achieved via magnetic field application

Compatible with Rapid Single Flux Quantum logic

Abstract

The $\varphi$ Josephson junction has a doubly degenerate ground state with the Josephson phases $\pm\varphi$. We demonstrate the use of such a $\varphi$ Josephson junction as a memory cell (classical bit), where writing is done by applying a magnetic field and reading by applying a bias current. In the "store" state, the junction does not require any bias or magnetic field, but just needs to stay cooled for permanent storage of the logical bit. Straightforward integration with Rapid Single Flux Quantum logic is possible.