Single- and Two-Qubit Quantum Gates to Bottom-up Crafted Spin Qubits

  • Datum:

    Donnerstag 26.04.2026, 15.00 Uhr

  • Referent:

    Dr. Soo-hyon Phark
    Center for Quantum Nanoscience, Institute for Basic Science, Korea

  • Abstract: Scanning tunneling microscopy (STM) combined with electron spin resonance (ESR) [1] enables bottom-up designed electron spin qubit platforms on solid surfaces, driven and read out in an all- electrical fashion.[2,3] However, the demonstration of universal quantum gates has remained a challenging task due to poor lifetime and quantum coherence on the order of ~100 ns in the initial physical setup: Ti atoms on a two-monolayer MgO/Ag [3]. In this talk, I will first present a dramatic increase in the lifetime and coherence time of bottom-up crafted multi-spin nanostructures using Ti atoms on three-monolayer MgO/Ag [4]. Second, I will show a demonstration of universal quan-tum gates and the implementation of quantum state tomography to these tailored single-, two-qubit systems. A survey on inherent challenges in hand and outlook of this novel qubit platform will follow.[5,6] 

     

    [1] S. Baumann et al. Science 350, 417-420 (2015) [2] K. Yang et al. Science 366, 509-512 (2019) [3] Y. Wang et al. Science 382, 87-92 (2023) [4] S. Phark et al. Nat. Commun. 17, 1609 (2026) [5] C. Wolf, A. J. Heinrich, S. Phark, ACS Nano 18, 28469-28479 (2024) [6] S. Phark et al. "Roadmap on atomically-engineered quantum platforms" Nano Futures 9, 032001 (2025)