International Collaboration in Chemistry: Suppressing Decoherence in Crystals Through Controlled Chemical Disorder

Montana State University, Bozeman MT

Investigators

Abstract

The rapidly developing field of quantum information science (QIS) exploits the unique properties of quantum systems to process, store, and transmit data in ways that are not tenable with classical information systems. For many applications of QIS, a "quantum memory" that can store and recall quantum states on demand is an urgently needed enabling component. This project pursues a new approach by introducing controlled chemical disorder into high-quality crystals to inhibit the "decoherence" processes that corrupt stored quantum information and limit the performance of existing memories. This international collaboration funded by the Division of Chemistry through the Chemical Structure, Dynamics and Mechanisms B program and the French ANR, combines teams with expertise in diverse areas ranging from solid-state chemistry and quantum physics to non-linear optics and information theory to solve this outstanding problem. Advancing the capabilities of quantum memory technology is of strategic importance given the broad need in our society to transmit information in a way that is and remains absolutely secure. In addition, the materials developed in this project have applications in many other photonic technologies including classical optical signal processing, ultra-stable optical clocks, and solid-state lasers. This collaboration addresses a critical need for new photonic materials with low quantum decoherence by introducing specific types of chemical disorder in crystals. Of all the optically addressed quantum memories being investigated, rare-earth ions in crystals at cryogenic temperatures stand out as one of the most promising light-matter interfaces that can store and recall the quantum states of light with high fidelity, efficiency, and bandwidth. This project investigates how incorporation of substitutional chemical dopants, introduction of defects such as oxygen vacancies, and weak local perturbations of chemical bonds due to compositionally induced lattice strain can disrupt the ion-ion, spin-ion, and photon-ion interaction mechanisms responsible for decoherence dynamics that limit the performance of quantum memories. This new material chemistry solution for developing low-decoherence materials coordinates fundamental studies of material properties and chemistry, design and synthesis of materials, and practical tests of performance in quantum memory demonstrations to develop a telecommunications-compatible system for efficient teleportation of quantum states between light and matter in quantum communication and computing systems.