Spin/Phonon Dynamics in Single Molecular Magnets: I. quantum embedding

TL;DR

This paper presents a systematic quantum embedding scheme to analyze and simulate spin-phonon interactions in single molecular magnets, enabling efficient computation of spin relaxation times relevant for quantum information applications.

Contribution

The work introduces a novel projection/embedding method that consolidates spin-phonon couplings into collective degrees of freedom, simplifying the analysis of spin dynamics in molecular magnets.

Findings

Applied to VOPc(OH)8, computed spin relaxation times consistent with experimental data.

The embedding scheme reduces computational complexity for simulating spin relaxation.

The method is general and applicable to various single-molecule magnets and qubits.

Abstract

Single molecular magnets (SMMs) and Metal-Organic Frameworks (MOFs) attract significant interest due to their potential in quantum information processing, scalable quantum computing, and extended lifetimes and coherence times. The limiting factor in these systems is often the spin dephasing caused by interactions and couplings with the vibrational motions of the molecular framework. This work introduces a systematic projection/embedding scheme to analyze spin-phonon dynamics in molecular magnets. This scheme consolidates all spin/phonon couplings into a few collective degrees of freedom. quantum mechanically. Using parameters obtained from ab initio methods for spin/phonon coupling via Zeeman interaction, we apply this approach to compute the electronic spin relaxation times for a single-molecule qubit \ce{VOPc(OH)8}, which features a single unpaired electron localized on the central vanadium atom. However, our general embedding scheme can be applied to any single-molecule magnet or qubit MOF with any coupling/interaction Hamiltonian. This development offers a crucial tool for simulating spin relaxation in complex environments with significantly reduced computational complexity.