Path integral simulation of exchange interactions in CMOS spin qubits

TL;DR

This paper introduces a path integral Monte Carlo algorithm to accurately estimate exchange interactions in silicon quantum dots, aiding the design and analysis of CMOS spin qubits for quantum computing.

Contribution

The paper presents a novel PIMC method for modeling exchange interactions in 3D quantum dots, benchmarked against FCI, and demonstrates its application to disorder effects in CMOS devices.

Findings

PIMC accurately estimates exchange interactions in silicon quantum dots.

Benchmarking shows agreement with full configuration interaction simulations.

Single charge traps significantly affect exchange interactions, impacting device tolerance.

Abstract

The boom of semiconductor quantum computing platforms created a demand for computer-aided design and fabrication of quantum devices. Path integral Monte Carlo (PIMC) can have an important role in this effort because it intrinsically integrates strong quantum correlations that often appear in these multi-electron systems. In this paper we present a PIMC algorithm that estimates exchange interactions of three-dimensional electrically defined quantum dots. We apply this model to silicon metal-oxide-semiconductor (MOS) devices and we benchmark our method against well-tested full configuration interaction (FCI) simulations. As an application, we study the impact of a single charge trap on two exchanging dots, opening the possibility of using this code to test the tolerance to disorder of CMOS devices. This algorithm provides an accurate description of this system, setting up an initial step to integrate PIMC algorithms into development of semiconductor quantum computers.