Sommaire:

Controlling and detecting individual spins in solids is interesting for high-resolution magnetic resonance spectroscopy and quantum computing. I will present a new set of methods that we have recently developed to do so, at millikelvin temperatures. The key idea is to count the microwave photons that an electron spin emits after excitation, in complete analogy with optical fluorescence [1]. The spin radiative rate is enhanced via the spin Purcell effect, by coupling the spins to an on-chip planar superconducting microwave resonator [2]. Microwave photon counting is performed using a detector that we have developed and which is based on a superconducting transmon qubit [3]. We detect individual Er3+ spins in a CaWO4 crystal [4]. Using an electron spin, we sense individual 183W nuclear spins. We achieve nuclear spin readout, polarization, and coherent control [5]. The nuclear spins have seconds-long coherence times. We also develop new control methods based on stimulated Raman microwave drives. Using an Er3+ spin strongly coupled to two 183W spins, we demonstrate a two-nuclear-spin-qubit gate, and generate an entangled state with second-long lifetime [6]. [1] Albertinale et al., Nature 600, 434 (2021) [2] Bienfait et al., Nature 531, 74 (2016) [3] Balembois et al., PRApplied 21, 014043 (2024) [4] Wang et al., Nature 619, 276 (2023) [5] Travesedo et al., arXiv:2408.14282 [6] O'Sullivan et al., arxiv:24LF.LF432

Pour plus d'informations, merci de contacter Finco A.