Multi-user equipment approved in grant 2024/08450-0: D281-SNSPD: system of superconducting nanowire single-photon detectors

• Grant number: 25/03500-1
• Support Opportunities: Multi-user Equipment Program
• Start date: May 01, 2025
• End date: April 30, 2032
• Field of knowledge: Physical Sciences and Mathematics - Physics - General Physics
• Principal Investigator: Rafael Ferreira Pinto do Rego Barros
• Grantee: Rafael Ferreira Pinto do Rego Barros
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/08450-0 - StruQT - Deploying Structured light for Quantum Technologies, AP.QUTIA.JP

Abstract

The state of the art is Quantum. Nearly a hundred years after the foundations of quantum science started to be built, quantum technologies nowadays advance at full steam into the so-called second quantum revolution. The quantum technological package includes quantum computers, which have the potential of outperforming classical machines in specifc tasks; Quantum communications, which enable fundamentally secure communication links regardless of what the future technology might bring; Quantum sensing and metrology, which enable enhanced sensitivity and/or resolution in specific measurements, harnessing fundamental features of quantum states which are unavailable for classical resources; Quantum simulators, which use tractable and controllable quantum systems to emulate problems that are hard for classical computers, allowing new advances in health sciences, chemistry, and logistics. Many of these technologies, although recent, already left the developing stage and are on the verge of commercial large-scale deployment. A particularly versatile platform for developing quantum technologies is light. Light travels fast and is inherently robust to decoherence through interactions with the environment, being the most logical information carrier for secure quantum communication (QComms). The prime example of light-based QComms is quantum key distribution (QKD), i.e., the distribution of cryptographic keys secured by the principles of quantum mechanics. QKD is undoubtedly the most mature branch of quantum technologies, partly due to the fast-approaching threat posed by quantum computers (QC) to the privacy of data encrypted by public keys - all data secured with public-key cryptography can nowadays be harvested to be decrypted later on when quantum computers (or by classical computers with algorithms yet to be developed) are available. In contrast, secret keys shared via QKD allow the use of the one-time pad encryption method, with which privacy is ensured even against infinite computational resources.One important feature of photonic quantum platforms is that the generation, control and measurement of quantum states of light are well-developed fields, leveraging the maturity of fundamental quantum optics research and the recent technological developments in the sensing of quantum optical signals. In particular, the growing field of structured light has brought many new insights and developments to quantum optics, enabling the encoding and readout of quantum information in the shape that light fields have in space, time, and polarization. Structured quantum light fetures in many recent and remarkable applications in quantum communications and metrology, and is expected to play an important role in potential photonic quantum computers. In this context, it is cleat that great efforts towards the development of structured light-based quantum technologies are not only timely, but also strategic. On account of that, I bring forward the QStruct proposal. The proposal presents a feasible two-step project to deploy optical quantum technologies in the state of São Paulo, purposefully exploring the structured light toolbox. First, I propose to establish an advanced quantum optics laboratory in the university of São paulo, the QSlab - USP, focused not only on proof-of-principle research on structured quantum light, but also on real-world applications of quantum optics solutions in quantum communications, and metrology. Second, I plan to realize the first connections of a hybrid quantum network in São Paulo, the QneSP, distributing entangled photons via the existing fiber infrastructure and setting a new free-space quantum channel across the city skyline. The success of the QStruct proposal will result in the start of one of the first quantum communication infrastructures in the country, and in the establishment of a world-class research group in the field of optical quantum technologies. (AU)