title: Enhancing quantum sensing sensitivity by a quantum memory.
abstract: In quantum sensing, precision is typically limited by the maximum time interval over which phase can be accumulated. Memories have been used to enhance this time interval beyond the coherence lifetime and thus gain precision. Here, we demonstrate that by using a quantum memory an increased sensitivity can also be achieved. To this end, we use entanglement in a hybrid spin system comprising a sensing and a memory qubit associated with a single nitrogen-vacancy centre in diamond. With the memory we retain the full quantum state even after coherence decay of the sensor, which enables coherent interaction with distinct weakly coupled nuclear spin qubits. We benchmark the performance of our hybrid quantum system against use of the sensing qubit alone by gradually increasing the entanglement of sensor and memory. We further apply this quantum sensor-memory pair for high-resolution NMR spectroscopy of single (13)C nuclear spins.
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Sebastian
authors: S
authors: Zaiser
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Torsten
authors: T
authors: Rendler
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Ingmar
authors: I
authors: Jakobi
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Thomas
authors: T
authors: Wolf
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Sang-Yun
authors: 0000-0003-1777-980X
authors: SY
authors: Lee
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Samuel
authors: S
authors: Wagner
authors: Department of Chemistry, Technical University Munich, Lichtenbergstrasse 4, Garching 85747, Germany.
authors: Ville
authors: V
authors: Bergholm
authors: Department of Chemistry, Technical University Munich, Lichtenbergstrasse 4, Garching 85747, Germany.
authors: Thomas
authors: T
authors: Schulte-Herbrüggen
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Philipp
authors: 0000-0003-2146-0412
authors: P
authors: Neumann
authors: 3rd Physics Institute, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70569, Germany.
authors: Jörg
authors: J
authors: Wrachtrup
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D045663:Quantum Dots / Q000737:chemistry*