$\pi$-junction qubit in monolayer graphene

TL;DR

This paper proposes a novel graphene-based $$-junction qubit design that leverages tunable Josephson physics for quantum computing, eliminating the need for ferromagnets and enabling various qubit operations.

Contribution

It introduces a new approach to create $$-junction qubits in graphene without ferromagnets and demonstrates how to implement key quantum gates.

Findings

Graphene can host $$-junctions without ferromagnets.

External flux and gate voltages can control the qubits.

The paper details implementation of phase and exchange gates.

Abstract

We propose to combine the advantages of graphene, such as easy tunability and long coherence times, with Josephson physics to manufacture qubits. If these qubits are built around a 0 and $\pi$ junction they can be controlled by an external flux. Alternatively, a d-wave Josephson junction can itself be tuned via a gate voltage to create superpositions between macroscopically degenerate states. We show that ferromagnets are not required for realizing $\pi$ junction in graphene, thus considerably simplifying its physical implementation. We demonstrate how one qubit gates, such as arbitrary phase rotations and the exchange gate, can be implemented.