| Zusammenfassung |
Quantum effects play a fundamental role in chemistry, yet the potential for chemical systems to carry out quantum information science (QIS) tasks remains largely unexplored. Of particular interest is entanglement—one of the key quantum resources in QIS – which remains difficult to measure and control in chemical systems. This project aims to change that by developing new experimental techniques to probe quantum correlations in the electron spins of molecular systems at room temperature. Our approach leverages nanophotonic cavities, specifically a metallic nanogap structure known as the nanoparticle-on-mirror (NPoM) platform , to enhance single-molecule optical measurements. This self-assembled structure provides extreme light confinement, amplifying optical signals and allowing for unprecedented sensitivity in detecting and manipulating molecular spins. Using this platform, we will achieve the first room-temperature optically-detected magnetic resonance (ODMR) at the single-molecule level, a critical milestone toward using organic molecules for quantum information science. By uniting nanophotonics, quantum optics, and spin photophysics, this project will open new frontiers in molecular quantum science. The ability to probe and manipulate spin entanglement at room temperature could impact a wide range of fields, from quantum computing and sensing to novel optoelectronic materials and chemically-inspired quantum processes. The project is structured into three key work packages: Single-molecule ODMR with nanophotonics: We will harness NPoM-enhanced optical fields to detect and control electron spins in individual molecules. By using fluctuation spectroscopy and single-photon detection, we will overcome traditional limitations of ODMR, which has previously only been possible at cryogenic temperatures for single organic molecules. These advancements will enable high-fidelity readout of spin states, a crucial step for quantum networks based on molecular qubits. Probing quantum correlations in molecular processes: We will explore how spin-entangled triplet states evolve in processes like singlet fission (SF) and triplet-triplet annihilation (TTA). By embedding SF and TTA-active molecules in the NPoM platform, we will measure their quantum coherence in real time using single-molecule photon correlation spectroscopy. This will reveal how quantum entanglement persists or degrades in molecular systems, offering new insights into fundamental quantum chemistry. Demonstrating chemical Bell inequalities: Building on our ODMR and SF/TTA studies, we will design an experiment to demonstrate Bell inequality violations in a chemical system—something never before achieved. By manipulating molecular spin states with microwave pulses and detecting the resulting photon correlations, we will provide direct evidence of nonlocal quantum behavior in organic molecules. This result would mark a major breakthrough, positioning molecular spins as viable architectures for quantum technologies. |
