Unlocking the Potential of Photoexcited Molecular Electron Spins for Room Temperature Quantum Information Processing

TL;DR

This paper demonstrates a room-temperature molecular spin system with millisecond relaxation times and photoactivation capabilities, advancing quantum information processing potential with organic radicals in viscous hosts.

Contribution

It introduces a novel organic radical system with tunable quantum spin properties and photoactivation, enhancing molecular media for microwave-based quantum applications.

Findings

Millisecond-long spin-lattice relaxation at room temperature

Microsecond-long phase memory times achieved

Photo-activated spin polarization demonstrated

Abstract

Future information processing technologies like quantum memory devices have the potential to store and transfer quantum states to enable quantum computing and networking. A central consideration in practical applications for such devices is the nature of the light-matter interface which determines the storage state density and efficiency. Here, we employ an organic radical, $\alpha$,$\gamma$-bisdiphenylene-$\beta$-phenylallyl (BDPA) doped into an o-terphenyl host to explore the potential for using tuneable and high-performance molecular media in microwave-based quantum applications. We demonstrate that this radical system exhibits millisecond-long spin-lattice relaxation and microsecond-long phase memory times at room temperature, while also having the capability to generate an oscillating spin-polarized state using a co-dissolved photo-activated tetraphenylporphyrin moiety, all enabled by using a viscous liquid host. This latest system builds upon collective wisdom from previous molecules-for-quantum literature by combining careful host matrix selection, with dynamical decoupling, and photoexcited triplet-radical spin polarisation to realise a versatile and robust quantum spin medium.