Special AEP Seminar: Andrea Morello (UNSW Sydney)
Schroedinger cat in a silicon box: quantum information and quantum foundations
I will present recent experiments, and exciting new directions, for the use of high-spin nuclei in silicon for quantum information, quantum foundations, and spin-mechanics entanglement. Nuclear spins in silicon are among the most coherent quantum objects to be found in the solid state. They have infinite relaxation time, and second-scale coherence time [1]. By using the I=7/2, 8-dimensional nucleus of antimony [2], we have prepared a nuclear Schroedinger cat within a functional nanoelectronic device [3]. This can be used to encode a cat-qubit similar to the bosonic encodings used in microwave cavities, but with atomic size, and even more extreme noise bias.
We then used this and other nonclassical states to perform a curious experiment, where the quanutmness of the state is certified by monitoring its uniform precession, in seeming contradiction with Ehrenfest’s theorem [4].
High-spin nuclei possess a quadrupole moment that couples them to lattice strain [5]. I will discuss plans to entangle a single nuclear spin with a MHz-range mechanical oscillator, and perspectives to scale up the mass of the oscillator to test gravitational collapse models.
[1] J. Muhonen et al., Nature Nanotechnology 9, 986 (2014)
[2] S. Asaad, V. Mourik et al., Nature 579, 205 (2020)
[3] X. Yu et al., Nature Physics 21, 362 (2025)
[4] A. Vaartjes et al., Newton 1, 100017 (2025)
[5] L. O’Neill et al., Applied Physics Letters 119, 174001 (2021)
Bio: Andrea Morello is an electrical engineer and a quantum physicist in the School of Electrical Engineering and Telecommunications at the University of New South Wales Sydney, Australia. He obtained a M.Eng. in electronics engineering at the Politecnico di Torino (1998), a Ph.D. in experimental physics at the Kamerlingh Onnes Laborary in Leiden (2004), followed by a postdoc at the University of British Columbia in Vancouver. He joined UNSW in 2006, where he is now the Scientia Professor of Quantum Engineering at the School of Electrical Engineering and Telecommunications, an Australian Research Council Laureate Fellow, and a Program Manager in the ARC Centre of Excellence for Quantum Computation and Communication Technology (CQC2T). His research is aimed at building a quantum computer based on single spins in silicon. In addition to the research, Andrea is actively engaged in science outreach and education.
