Analog of a quantum heat engine using a single-spin qubit

TL;DR

This paper demonstrates an experimental realization of a single-spin qubit in silicon acting as a quantum heat engine or refrigerator, revealing quantum interference effects in the coherent regime.

Contribution

It introduces a minimal quantum heat machine using a single-spin qubit in silicon, combining experimental implementation with theoretical analysis of both incoherent and coherent regimes.

Findings

System can operate as a heat engine or refrigerator in incoherent regime

Quantum interference fringes observed in source-drain current in coherent regime

Experimental and theoretical framework established for single-spin quantum heat devices

Abstract

A quantum two-level system with periodically modulated energy splitting could provide a minimal universal quantum heat machine. We present the experimental realization and the theoretical description of such a two-level system as an impurity electron spin in a silicon tunnel field-effect transistor. In the incoherent regime, the system can behave analogously to either an Otto heat engine or a refrigerator. The coherent regime could be described as a superposition of those two regimes, producing specific interference fringes in the observed source-drain current.