报告时间：2025年7月25日 下午14:00(14:00, July.25, 2025)
报告地点：物质科研楼A309(Room A309, Material Science Building)
报告人：Dr. Michael Trupke
Austrian Academy of Sciences, Institute for Quantum Optics and Quantum Information
报告题目/Title：Quantum Science and Technology at IQOQI-Vienna
报告摘要/Abstract：
Following a brief introduction of the Institute, I will present three experiments being developed in the Quantum Technology Unit of IQOQI-Vienna.
Nitrogen-vacancy (NV) centres in diamond have spearheaded the development of spin centres for quantum technology, chiefly towards devices for quantum sensing. Their sensitivity is limited, in part, by the spin contrast and by the collection of photoluminescence. I will present a method to improve the spin contrast by tailoring the optical initialization to the NV’s ionization cycle[1], as well as progress on electrical readout, with a view to enhanced state readout[2].
Vanadium in silicon carbide has emerged as a strong candidate for applications in quantum photonics [3], [4], [5], [6], [7], [8]: It has a strong optical transition at 1.3 µm, compatible with optical fiber networks, a long-lived electron spin, and is hosted in a material that is available with high quality at an industrial scale. Our investigations have resulted in significant advances in our understanding of this remarkable system, the control of its electron spin, and the development of photonic interfaces for quantum networks[6], [9], [10].
Magnetic levitation of superconductors on the microgram scale offers a promising experimental platform towards preparation of non-classical states of massive objects, an important milestone towards the exploration of gravitational interactions between quantum mechanical systems. A high degree of decoupling of the particles from the environment has already been demonstrated, with mechanical Q-factors reaching 2.6×107 at millikelvin temperatures[11]. To feedback-cool a harmonic oscillator to its lowest energy state and move towards quantum control of its motion, it is necessary to reach a spatial resolution on the scale of the ground state extent, with a measurement rate that exceeds the decoherence rate. To this end, we have recently implemented interferometric readout of the mechanical motion in both the optical (in preparation) and microwave regimes[11], [12].
References
[1]D. Wirtitsch et al., ‘Exploiting ionization dynamics in the nitrogen vacancy center for rapid, high-contrast spin, and charge state initialization’, Phys. Rev. Research, vol. 5, no. 1, p. 013014, Jan. 2023, doi: 10.1103/PhysRevResearch.5.013014.
[2]M. Gulka et al., ‘Room-temperature control and electrical readout of individual nitrogen-vacancy nuclear spins’, Nat Commun, vol. 12, no. 1, p. 4421, Dec. 2021, doi: 10.1038/s41467-021-24494-x.
[3]L. Spindlberger et al., ‘Optical Properties of Vanadium in 4 H Silicon Carbide for Quantum Technology’, Phys. Rev. Applied, vol. 12, no. 1, p. 014015, Jul. 2019, doi: 10.1103/PhysRevApplied.12.014015.
[4]C. M. Gilardoni, I. Ion, F. Hendriks, M. Trupke, and C. H. van der Wal, ‘Hyperfine-mediated transitions between electronic spin-1/2 levels of transition metal defects in SiC’, New J. Phys., vol. 23, no. 8, p. 083010, Aug. 2021, doi: 10.1088/1367-2630/ac1641.
[5]B. Tissot, M. Trupke, P. Koller, T. Astner, and G. Burkard, ‘Nuclear spin quantum memory in silicon carbide’, Phys. Rev. Research, vol. 4, no. 3, p. 033107, Aug. 2022, doi: 10.1103/PhysRevResearch.4.033107.
[6]T. Astner et al., ‘Vanadium in silicon carbide: telecom-ready spin centres with long relaxation lifetimes and hyperfine-resolved optical transitions’, Quantum Sci. Technol., vol. 9, no. 3, p. 035038, Jul. 2024, doi: 10.1088/2058-9565/ad48b1.
[7]P. Koller, T. Astner, B. Tissot, G. Burkard, and M. Trupke, ‘Strain-enabled control of the vanadium qudit in silicon carbide’, Phys. Rev. Materials, vol. 9, no. 4, p. L043201, Apr. 2025, doi: 10.1103/PhysRevMaterials.9.L043201.
[8]P. Cilibrizzi et al., ‘Ultra-narrow inhomogeneous spectral distribution of telecom-wavelength vanadium centres in isotopically-enriched silicon carbide’, Nature Communications, vol. 14, no. 1, p. 8448, Dec. 2023, doi: 10.1038/s41467-023-43923-7.
[9]J. Fait et al., ‘High finesse microcavities in the optical telecom O-band’, Appl. Phys. Lett., vol. 119, no. 22, p. 221112, Nov. 2021, doi: 10.1063/5.0066620.
[10]K. Nemoto et al., ‘Photonic Architecture for Scalable Quantum Information Processing in Diamond’, Physical Review X, vol. 4, no. 3, Aug. 2014, doi: 10.1103/PhysRevX.4.031022.
[11]J. Hofer et al., ‘High- Q Magnetic Levitation and Control of Superconducting Microspheres at Millikelvin Temperatures’, Phys. Rev. Lett., vol. 131, no. 4, p. 043603, Jul. 2023, doi: 10.1103/PhysRevLett.131.043603.
[12]P. Schmidt et al., ‘Remote sensing of a levitated superconductor with a flux-tunable microwave cavity’, Phys. Rev. Applied, vol. 22, no. 1, p. 014078, Jul. 2024, doi: 10.1103/PhysRevApplied.22.014078.
