Let me announce my CERN colloquium this Thursday, August 22, 2019, 16:30-17:30 entitled “The argument against quantum computers.” If you are at CERN or the neighborhood, please please come to the lecture. (Tea and coffee will be served at 16:00. ) If you are further away, there is a live broadcast.
A few weeks ago I uploaded to the arXive a new paper with the same title “The argument against quantum computers“. The paper will appear in the volume: Quantum, Probability, Logic: Itamar Pitowsky’s Work and Influence, Springer, Nature (2019), edited by Meir Hemmo and Orly Shenker. A short abstract for the lecture and the paper is:
We give a computational complexity argument against the feasibility of quantum computers. We identify a very low complexity class of probability distributions described by noisy intermediate-scale quantum computers, and explain why it will allow neither good-quality quantum error-correction nor a demonstration of “quantum supremacy.” Some general principles governing the behavior of noisy quantum systems are derived.
The new paper and lecture have the same title as my 2018 interview with Katia Moskvitch at Quanta Magazine (see also this post). Note that Christopher Monroe has recently contributed a very interesting comment to the Quanta article. My paper is dedicated to the memory of Itamar Pitowsky, and for more on Itamar see the post Itamar Pitowsky: Probability in Physics, Where does it Come From? See also this previous post for two other quantum events in Jerusalem: a seminar in the first semester and a winter school on The Mathematics of Quantum Computation on December 15 – December 19, 2019.
A slide from a lecture by Scott Aaronson where he explains why soap bubble computers cannot solve the NP-complete Steiner-tree problem. Noisy intermediate scale quantum (NISQ) circuits are computationally much more primitive than Scott’s soap bubble computers and this will prevent them from achieving neither “quantum supremacy” nor good quality quantum error correcting codes. (source for the picture)
Low-entropy quantum states give probability distributions described by low degree polynomials, and very low-entropy quantum states give chaotic behavior. Higher entropy enables classical information.