Summary: Multilinear Formulas and Skepticism of Quantum
Computing #
Scott Aaronson +
ABSTRACT
Several researchers, including Leonid Levin, Gerard 't Hooft,
and Stephen Wolfram, have argued that quantum mechan­
ics will break down before the factoring of large numbers be­
comes possible. If this is true, then there should be a natural
set of quantum states that can account for all quantum com­
puting experiments performed to date, but not for Shor's
factoring algorithm. We investigate as a candidate the set of
states expressible by a polynomial number of additions and
tensor products. Using a recent lower bound on multilinear
formula size due to Raz, we then show that states arising in
quantum error­correction require
n##0 n) additions and ten­
sor products even to approximate, which incidentally yields
the first superpolynomial gap between general and multilin­
ear formula size of functions. More broadly, we introduce a
complexity classification of pure quantum states, and prove

Source: Aaronson, Scott - Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology (MIT)

Collections: Physics; Computer Technologies and Information Sciences