[2603.22401] Probabilistic modeling over permutations using quantum computers

Quantum Physics arXiv:2603.22401 (quant-ph) [Submitted on 23 Mar 2026] Title:Probabilistic modeling over permutations using quantum computers Authors:Vasilis Belis, Giulio Crognaletti, Matteo Argenton, Michele Grossi, Maria Schuld View a PDF of the paper titled Probabilistic modeling over permutations using quantum computers, by Vasilis Belis and 4 other authors View PDF HTML (experimental) Abstract:Quantum computers provide a super-exponential speedup for performing a Fourier transform over the symmetric group, an ability for which practical use cases have remained elusive so far. In this work, we leverage this ability to unlock spectral methods for machine learning over permutation-structured data, which appear in applications such as multi-object tracking and recommendation systems. It has been shown previously that a powerful way of building probabilistic models over permutations is to use the framework of non-Abelian harmonic analysis, as the model's group Fourier spectrum captures the interaction complexity: "low frequencies" correspond to low order correlations, and "high frequencies" to more complex ones. This can be used to construct a Markov chain model driven by alternating steps of diffusion (a group-equivariant convolution) and conditioning (a Bayesian update). However, this approach is computationally challenging and hence limited to simple approximations. Here we construct a quantum algorithm that encodes the exact probabilistic model -- a classically intrac...