IFIMAC+ICMM Joint Seminar Series focuses on cutting-edge research on condensed matter physics, bringing European speakers to our Cantoblanco Campus, this year via Zoom. You need to be subscribed to our mailing list at the link provided below to get the links to the seminar room. https://listas-correo.uam.es/sympa/subscribe/seminarios-ifimac-icmm-l.

Scaling silicon-based quantum computers using CMOS technology

M. Fernando Gonzalez-Zalba

Quantum Motion Technologies

The spins of isolated electrons in silicon are one of the most promising solid-state systems on which to implement quantum information processing. With the recent demonstrations of long coherence times [1], high-fidelity spin readout [2], and one- and two-qubit gates [3-5], the basic requirements to build a quantum computer have been fulfilled. Now, scaling the technology to a number of qubits sufficiently large to perform computationally relevant calculations is one of the major objectives and several proposals for large scale integration have been put forward [6-7].

Recently, important developments in the field of nanodevice engineering have shown that qubits can be manufactured in a similar fashion to field-effect transistors (FET) [8], creating an opportunity to leverage the scaling capabilities of the semiconductor industry to address the challenge. Quantum computing with silicon transistors fully profits from the most established industrial technology to fabricate large scale integrated circuits while facilitating the integration with conventional electronics for fast data processing of the binary outputs of the quantum processor.

In this talk, I will present a series of results on CMOS transistors at milikelvin temperatures that show this technology could provide a platform on to which implement electron-spin qubits. I will specially concentrate on our efforts to develop a qubit specific measurement technique that is accurate and scalable while being compatible with the industrial fabrication processes [9-11]. With that, I will show the first measurements of an electron spin in a silicon industry-fabricated device [12] and finally, I will present results on how digital and quantum devices can be combined with this technique to time-multiplex the readout of several qubits [13].


[1] M. Veldhorst, Nature, 526, 410 (2015)

[2] A. Morello, Nature 467, 687 (2010)

[3] D. M. Zajac, Science,10.1126/science.aao5965 (2017)

[4] J. Yoneda, Nat. Nanotech. 13 102 (2018)

[5] T. F.Watson, Nature 555 633 (2018)

[6] L. M. K. Vandersypen, npj Quantum Information 3, 34 (2017)

[7] M. Veldhorst, Nat. Commun. 8, 1766 (2017)

[8] R. Maurand, Nat. Commun. 7 13575 (2016)

[9] M. F. Gonzalez-Zalba, Nat. Commun. 6 6084 (2015)

[10] T. Lundberg , PRX in press,  arXiv:1910.10118 (2020)

[11] D. J. Ibberson, arXiv:2004.00334 (2020)

[12] V. N. Ciriano-Tejel, arXiv:2005.07764 (2020)

[13] S. Schaal, Phys Rev App 9 054016 (2018) and Nat Elect 2 236 (2019)