Majorana Fermions Signatures in Macroscopic Quantum Tunneling

TL;DR

This paper investigates how topological superconducting phases influence macroscopic quantum tunneling in rf-SQUIDs, revealing shifts in tunneling rates and energy levels that serve as signatures of Majorana fermions.

Contribution

It demonstrates that topological order alters tunneling dynamics in rf-SQUIDs, providing new insights into detecting Majorana fermions through quantum tunneling signatures.

Findings

Topological order shifts tunneling rates and quantum levels.

Signatures are enhanced in slowly fluctuating regimes.

Results impact the understanding of $\pi$-junction loops.

Abstract

Thermodynamic measurements of magnetic fluxes and I-V characteristics in SQUIDs offer promising paths to the characterization of topological superconducting phases. We consider the problem of macroscopic quantum tunneling in an rf-SQUID in a topological superconducting phase. We show that the topological order shifts the tunneling rates and quantum levels, both in the parity conserving and fluctuating cases. The latter case is argued to actually enhance the signatures in the slowly fluctuating limit, which is expected to take place in the quantum regime of the circuit. In view of recent advances, we also discuss how our results affect a $\pi$-junction loop.