Programmable Microwave Source for Pulsed Electron Spin Resonance Scanning Tunneling Microscopy of Molecular Quantum Spin Centers
Abstract
1) Publicly releasable abstract:The purpose of this proposal is to request funding for new microwave electronics to upgrade an existing electron spin resonance scanning tunneling microscope (ESR-STM) to enable new pulsed ESR-STM measurements of molecular spin centers. To accomplish this we require an arbitrary waveform generator (AWG) to gate the output of a 40 GHz RF generator, an RF power amplifier to deliver high-power microwaves to our STM tunnel junction, and a TTL trigger board to synchronize our STM control, microwave output, and ESR readout. Pulsed ESR-STM is a new experimental technique that combines the quantum spin initialization, manipulation, and detection capabilities of traditional spin resonance with the atomic resolution and atomic manipulation protocols of STM. This new instrument will be ideal for characterizing the quantum coherent properties of individual spin centers at the atomic scale. Currently we possess the ability to perform continuous-wave ESR-STM, but what we are missing is the ability to perform pulsed ESR-STM measurements with arbitrary microwave pulse sequences that could enable the measurement of decoherence lifetimes and the operationof quantum gates at the molecular level. Pulsed ESR-STM would allow the execution of single- and double-qubit gates in new molecular-scale quantum computing architectures, the ability to switch on and off qubit coupling during the course of an algorithm, and thespatial resolution to carry out these measurements in a fully-integrated molecular-scale environment. Such measurements would support the efforts of a current MURI project that is working on a new molecular-based approach to quantum computing that involves the growth and characterization of bottom-up graphene nanoribbons (GNRs). This approach has the potential to overcome many of the significant challenges that face current implementations of quantum computers. For example, bottom-up chemical design offers a strategy tocreate #designer qubits# with tunable quantum properties and pre-engineered qubit-qubit interactions. This type of hierarchical chemical self-assembly provides a route towards cost-efficient, controlled scalability while also offering a platform for creating new hardware that can reach the ultimate physical limits of high-density circuitry. The equipment being requested here will be used to better understand the structure-function relationships of molecular qubits, to determine optimal strategies for achieving coherent quantum control of molecular qubits, for engineering switchable and robust qubit-qubit interactions at the molecular scale, for exploring new schemes to achieve supramolecular assembly of molecular-scale electronics, and for integrating molecular-scale quantum hardware with conventional macroscopic electronics.This is a fundamental research project that is not expected to produce any developmental items. Should any developmental items result from this work they will have both civilian and military applications.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2023
- Source ID
- N000142312817
Entities
People
- Michael F. Crommie
Organizations
- Office of Naval Research
- United States Navy
- University of California Regents