RUI: Using Colloidal Nanoparticles to Host Photogenerated Spin Qubit Pairs

Amherst College, Amherst MA

Investigators

Abstract

WIth support from the Chemical Structure, Dynamics & Mechanisms-B Program of the Chemistry Division, Jacob Olshansky of the Department of Chemistry and Jonathan Friedman of the Department of Physics and Astronomy at Amherst College will be developing and analyzing a new nanoparticle-based system that has potential to serve as a class of quantum bits (qubits) that can be initiated with light. The development of quantum computers and other quantum information science (QIS) technologies has received significant attention in recent years owing to its promise to revolutionize computing. However, the specific molecular systems that will comprise the qubits in these devices remain a challenge. In the current work, the Amherst team focuses on photogenerated (light-initiated) spin qubits that are designed to be generated in well-defined quantum states without requiring expensive millikelvin cooling devices. The team will explore a new nanoparticle-molecule conjugate system for hosting these photogenerated spin qubits. They will characterize these conjugates with both time-resolved optical and spin resonance measurements to evaluate their utility as qubit candidates. The investigations will involve undergraduate students in cutting-edge research that is both interdisciplinary and highly collaborative. The students trained through this work will be better positioned to pursue careers in the burgeoning field of QIS. Photogenerated spin qubit pairs (SQP) offer a promising platform for the development of QIS technologies since they are generated in well-defined (non-Boltzmann populated) spin states. The proposed work aims to expand the scope of the materials that can host these photogenerated SQPs. Specifically, conjugates of nanoparticles and organic molecules offer potential advantages over the all-organic systems typically used to support SQPs. These conjugates are expected to be synthetically tunable, and the unique spin environment provided by the nanoparticle may allow for qubit specific addressability within the qubit pair. The initial work suggests that SQPs hosted by conjugates of ZnO nanoparticles and organic dye molecules can be detected and characterized with electron paramagnetic resonance (EPR) techniques. The research team aims to build a deeper understanding of the spin states in these conjugates through iterative synthetic modifications and spin-state characterization using both custom-built and commercial EPR spectrometers. They plan to demonstrate spin-specific addressability and perform spin-qubit manipulations on multi-spin systems hosted by ZnO nanoparticles. Ultimately, the work could provide researchers with both new materials and potentially new techniques for exploring photogenerated SQPs in the context of QIS applications. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.