Separating quantum and classical efficient computation
Establish whether the class of problems solvable efficiently by quantum algorithms with bounded error (BQP) is strictly different from the class of problems solvable efficiently by classical algorithms; for example, show the existence (or nonexistence) of a decision problem in BQP that is not efficiently solvable by any classical randomized algorithm.
References
We don't really know if quantum computers are any different from classical computers, but we highly suspect they are.
— What You Shouldn't Know About Quantum Computers
(2405.15838 - Ferrie, 2024) in Myth 5: Quantum Computers Will Replace Digital Computers — BQP subsection
Shortly after, Fortnow and Rogers asked if the same is true relative to a \emph{random} oracle, a problem that remains open today.
— Quantum Speedups Require Structure or Depth
(2608.19158 - Blanc et al., 19 Aug 2026) in Section 5, subsection “Implications for random-oracle separations”
Quantum computers challenge the Strong Church-Turing thesis, but it remains unproven whether they can be efficiently simulated or not.
— On quantum channels: extreme points, topology, and categorical properties
(2608.20689 - Silva, 21 Aug 2026) in Chapter 1, Section "CPTP maps in Quantum Computation and Quantum Information Theory"