+++ONLINE COLLOQUIUM+++Quantum Information And Quantum Foundations With Spins In Silicon (Prof. Andrea Morello)

  • Datum: 11.05.2021
  • Uhrzeit: 11:00
  • Vortragende(r): Prof. Dr. Andrea Morello
  • Centre for Quantum Computation & Communication Technology, School of Electrical Engineering & Telecommunications, UNSW Sydney, Australia
Dopant atoms in silicon are a versatile platform for experiments in quantum information processing, as well as quantum foundations. The simplest incarnation, the 31P donor, was adopted in the first proposal for a silicon-based quantum computer [1]. The electron [2] and nuclear [3] spin of a 31P donor were the first qubit demonstrated in silicon, and went on to become among of the most coherent qubits in the solid state, with coherence times exceeding 30 seconds [4], and quantum gate fidelities approaching 99.99% [5].

In this talk I will present the state of the art and future directions for donor spins in silicon. For quantum information, the current focus is on two-qubit operations. An embryonic demonstration of an exchange-based two-qubit CROT gate was recently achieved [6], using a device in which we implanted a high dose of 31P donors. Future experiments will focus on using deterministic, counted single-ion implantation, for which we have recently demonstrated the capability to detect an individual ion with 99.87% confidence [7].
Heavier donors possess a high nuclear spin quantum number, which could be an important resource to encode error-protected logical qubits in its large Hilbert space [8]. Our group began the study of 123Sb donors for the goal of observing quantum chaotic dynamics in a single quantum system [9]. Understanding the interplay between chaos and quantum dynamics is a key aspect for the foundational question of how the classical world emerges from the quantum world [10]. Moreover, chaotic dynamics must be understood and controlled for the correct operation of quantum computers and quantum simulators. In the process of operating a single 123Sb nucleus, we (re)discovered the phenomenon of nuclear electric resonance, and applied it for the first time to a single nuclear spin [11].

[1] B. Kane, Nature 393, 133 (1998)
[2] J. Pla et al., Nature 489, 541 (2012)
[3] J. Pla et al., Nature 496, 334 (2013)
[4] J. Muhonen et al., Nature Nanotechnology 9, 986 (2014)
[5] J. Muhonen et al., J. Phys: Condens. Matter 27, 154205 (2015)
[6] M. Madzik et al., arXiv:2006.04483 (2020)
[7] A. Jakob et al., arXiv:2009.02892 (2020)
[8] J. Gross et al., arXiv:2005.10910 (2020)
[9] V. Mourik et al., Physical Review E 98, 042206 (2018)
[10] L. Sieberer et al., NPJ Quantum Information 5:78 (2019)
[11] S. Asaad et al., Nature 579, 205 (2020)

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