Geometrical optimization of spin clusters for the preservation of quantum coherence

TL;DR

This study explores how the geometry of spin clusters influences quantum coherence preservation, revealing that specific planar and tetrahedral configurations optimize coherence times in thermal environments.

Contribution

It introduces a geometrical approach to optimize spin cluster configurations for enhanced quantum coherence preservation, highlighting the importance of network connectivity and specific geometries.

Findings

Maximal planar graphs maximize coherence time.

Tetrahedral geometry offers optimal protection.

Coherence preservation does not always increase with more buffer spins.

Abstract

We investigate the influence of geometry on the preservation of quantum coherence in spin clusters subjected to a thermal environment. Assuming weak inter-spin coupling, we explore the various buffer network configurations that can be embedded in a plane. Our findings reveal that the connectivity of the buffer network is crucial in determining the preservation duration of quantum coherence in an individual central spin. Specifically, we observe that the maximal planar graph yields the longest preservation time for a given number of buffer spins. Interestingly, our results demonstrate that the preservation time does not consistently increase with an increasing number of buffer spins. Employing a quantum master equation in our simulations, we further demonstrate that a tetrahedral geometry comprising a four-spin buffer network provides optimal protection against environmental effects.