Multi-user equipment approved in grant 2024/08455-1: dilution refrigeration system

• Grant number: 25/08511-1
• Support Opportunities: Multi-user Equipment Program
• Start date: July 01, 2025
• End date: June 30, 2032
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Rodrigo da Silva Benevides
• Grantee: Rodrigo da Silva Benevides
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/08455-1 - Modular microwave-optical quantum transduction, AP.QUTIA.JP

Abstract

Achieving long-distance, efficient and faithful quantum communication is a major step for the quantum information community. It will allow the interconnection of different quantum processing units, an important step for the implementation of a quantum internet. Moreover, it will help to improve the processing capacity of quantum computers, allowing them tomultiplex and parallelize operations in distinct quantum processing units. Many works have been studying this possibility, using diverse methods and platforms. One major approach uses fully integrated devices, which could potentially be scaled up, but lack in robustness considering their sensitivity to optical power and microfabrication unpredictability. Another approach is based on the use of bulk materials or membranes inside free space optical cavities, which are very robust to power and thermalization, but demand intricate optical setup and vibration isolation systems inside dilution refrigerators, forbidding their scalability. In this project, I will follow an alternative path combining the best properties of both approaches. I will build a system composed of a superconducting qubit, an intermediate acoustic oscillator, and an optomechanical device to realize a full microwave-optical transduction process. To reach this goal, I will combine state-of-the-art micro Fabry-Pérot cavities, with demonstrated optical finesse exceeding one million, with surface acoustic waves controlled at the single phonon level via superconducting circuits. I propose a modular approach that eases the fabrication of each component, integrating them into a final device via bonding processes. The device will be able to perform bi-directional microwave-optical quantum transduction, paving the way to remote entanglement of distant superconducting-based quantum processing units. This project is well-situated in one of the main axes of the QuTIa call, i.e., to study quantum communications and frequency transducers. (AU)