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It’s been frustrating to watch Gutmann slowly slide. He hasn’t slid that far yet, I suppose. Don’t discount his voice, but don’t let him be the only resource for you to learn about quantum computing; fundamentally, post-quantum concerns are a sort of hard read in one direction, and Gutmann has decided to try a hard read in the opposite direction.
Page 19, complaining about lattice-based algorithms, is hypocritical; lattice-based approaches are roughly as well-studied as classical cryptography (Feistel networks, RSA) and elliptic curves. Yes, we haven’t proven that lattice-based algorithms have the properties that we want, but we haven’t proven them for classical circuits or over elliptic curves, either, and we nonetheless use those today for TLS and SSH.
Pages 28 and 29 are outright science denial and anti-intellectualism. By quoting Woit and Hossenfelder — who are sneerable in their own right for writing multiple anti-science books each — he is choosing anti-maths allies, which is not going to work for a subfield of maths like computer science or cryptography. In particular, p28 lies to the reader with a doubly-bogus analogy, claiming that both string theory and quantum computing are non-falsifiable and draw money away from other research. This sort of closing argument makes me doubt the entire premise.
The sibling comment gives a wider perspective. I’m going to only respond narrowly on that final paragraph’s original point.
String theories arise naturally from thinking about objects vibrating in spacetime. As such, they’ve generally been included in tests of particle physics whenever feasible. The LHC tested and (statistically) falsified some string theories. String theorists also have a sort of self-regulating ratchet which excludes unphysical theories, most recently excluding swampland theories. Most money in particle physics is going towards nuclear power, colliders like LHC or Fermilab’s loops, or specialized detectors like SK (a giant tank of water) or LIGO (artfully-arranged laser beams) which mostly have to sit still and not be disturbed; in all cases, that money is going towards verification and operationalization of the Standard Model, and any non-standard theories are only coincidentally funded.
So just by double-checking the history, we see that some string theories have been falsified and that the Standard Model, not any string theory, is where most funding goes. Hossenfelder and Woit both know better, but knowing better doesn’t sell books. Gutmann doesn’t realize, I think.