Could silicon enable a quantum computing revolution?

CIC nanoGUNE Seminars

M. Fernando Gonzalez-Zalba, Quantum Motion Technologies, Cambridge
nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
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Could silicon enable a quantum computing revolution? **Could silicon enable a quantum computing revolution?** M. Fernando Gonzalez-Zalba Lead Quantum Engineer and UKRI Future Leader Fellow at Quantum Motion Technologies The silicon metal-oxide-semiconductor transistor is the workhorse of the microelectronics industry. It is the building block of all major electronic information processing components such as microprocessors, memory chips and telecommunications microcircuits. By shrinking its size generation after generation, the computational performance, memory capacity and information processing speed has increased relentlessly. However, the process of miniaturization is bound to reach its fundamental physical limits in the next decades. New computing paradigms are hence paramount to overcome the technical limitations of silicon technology and to continue increasing the computation performance beyond simple multi-core approaches. Quantum computing offers exponential speed-up over several classical algorithms, and it is hence one of the most sought-after alternatives to conventional computing. However, finding the optimal physical system to process quantum information and scale it up to the large number of qubits necessary to run useful quantum algorithms remains a major challenge. Paradoxically, we are now starting to see that silicon technology itself could offer an optimal platform on which to fabricate scalable quantum circuits: Quantum computing with silicon transistors could profit from the most established industrial technology to fabricate large scale integrated circuits [1], a fact that facilitates the integration with conventional electronics for fast data processing of the binary outputs of the quantum processor [2,3]; all this offering long electron spin coherence times [4], high-fidelity spin readout [5], and one- and two-qubit gates [6-8], the basic physical requirements to build a quantum computer. First, in this talk, I will review the field of silicon-based quantum computing going from the basic physics that govern spin qubits in this material, all the way to the technological implementation, the state-of-the- art and the scaling challenges ahead. Secondly, I will present a series of results on industry- manufactured silicon transistors at milikelvin temperatures that show the technology could provide a platform on to which implement electron spin qubits including our new spin measurement technique that has enabled the first detection of electron spin dynamics in an industry- fabricated device [5,9]. Then, I will present results on how digital, analog, and quantum devices can be combined to perform readout at scale using time- and frequency-multiplexing [3]. Finally, will show a roadmap of how the architecture can be scaled up [10] and, if time allows, fundamental and technological side effects of doing research in silicon quantum computing [11, 12]. **References ** [1] M.F. Gonzalez-Zalba, Nat Elect 4 872 (2021) [2] S. Schaal, Nat Elect 2 236 (2019) [3] A. Ruffino, Nat Elect 5 53 (2022) [4] M. Veldhorst, Nature, 526, 410 (2015) [5] G.A.Oakes, arxiv2203.06608 (2022) [6] J. Yoneda, Nat. Nanotech. 13 102 (2018) [7] X. Xue, Nature 601 343 (2022) [8] A. Noiri, Nature 601 338 (2022) [9] V. N. Ciriano-Tejel, PhysRevX Q 2 010353 (2021) [10] O. Crawford, arxiv2201.02877 (2022) [11] L. Cochrane, Phys Rev Lett 128 197701 (2022) [12] T. Lundberg, Phys Rev X 10 041010 (2020) **Host:** J. M. Pitarke