Franz J. Schreiber
fjschreiber.bsky.social
Franz J. Schreiber
@fjschreiber.bsky.social
PhD student @ Eisert Group, FU Berlin. Quantum Information Theory
I mean I can actually imagine people trying challenges with NISQ computers down the line.
November 19, 2025 at 12:18 PM
Reposted by Franz J. Schreiber
Grover's quadratic speedup is provably optimal in the black-box setting. We expect general SAT to be essentially unstructured and as hard as the black-box setting (strong exponential time hypothesis). It's believable that Grover is optimal there. But this is not clear for 3-SAT.
November 14, 2025 at 6:50 AM
Also, thanks to my great collaborators, mxkramer.bsky.social, Alexander Nietner and @jenseisert.bsky.social!
November 14, 2025 at 6:50 AM
3-SAT is clearly more structured than SAT in general, as evidenced by the improved classical runtime of O(1.307^n) compared to the 2^n for SAT. Using Grover on top of a classical solver, this structure is only addressed classically, inherently capping the achievable speedup at quadratic.
November 14, 2025 at 6:50 AM
Grover's quadratic speedup is provably optimal in the black-box setting. We expect general SAT to be essentially unstructured and as hard as the black-box setting (strong exponential time hypothesis). It's believable that Grover is optimal there. But this is not clear for 3-SAT.
November 14, 2025 at 6:50 AM
To be clear: This line of research is not about exponential quantum advantages, but polynomial ones. 3-SAT is an NP-hard problem and is NOT expected to be efficiently solvable on a quantum computer.
November 14, 2025 at 6:50 AM
To get a worst-case scaling of the form O(c^n), we would need a lower bound on the gap of the SAT instance encoding Hamiltons. Unfortunately, we did not manage this and after talking to a few experts, this seems to be a difficult task. We leave this as an open problem.
November 14, 2025 at 6:50 AM
Regarding the algorithmic improvements, I particularly like our perfect hash family based scheme for parallelizing local measurements in the algorithm.
November 14, 2025 at 6:50 AM
Obvious candidate because strong numerical performance is known for this algorithm, but theoretical understanding is limited. We provide an expression for the worst-case runtime depending on the Hamiltonian gap as well as interesting algorithmic improvements.
November 14, 2025 at 6:50 AM
We look at such an algorithm in scirate.com/arxiv/2511.0..., namely the measurement-driven SAT solver from Benjamin, Zhao and Fitzsimons, which I think is an obvious candidate algorithm for this line of thought.
BZF algorithm: arxiv.org/abs/1711.02687
A measurement-driven quantum algorithm for SAT: Performance guarantees via spectral gaps and measurement parallelization
The Boolean satisfiability problem (SAT) is of central importance in both theory and practice. Yet, most provable guarantees for quantum algorithms rely exclusively on Grover-type methods that cap the...
scirate.com
November 14, 2025 at 6:50 AM
Reposted by Franz J. Schreiber
Here is the referee report for that paper. :) Same would apply here.
December 19, 2024 at 2:37 PM
Just looked for the code and there is a Julia package, I love that!
December 2, 2024 at 2:22 PM