Most strongly correlated systems are intractable. I look for the exceptions, the ones where correlations are driven by a handful of hidden variables.
Marco BiroliResearch Scholar (postdoctoral) · University of Chicago, since 2025.
Fig. 1 — resetting brownian gas
FIG. 1N non-interacting diffusers on the real line, reset together at
Poisson times (vertical marks). The reset events alone — no direct
interaction — couple them; the apparent independence is, by construction,
false. Biroli, Larralde,
Majumdar & Schehr, PRL 130, 207101 (2023).
— Lines of work
Three threads, one question.
01 — MACHINE LEARNING
The physics of learning
Where statistical mechanics meets generative modeling. Why a VAE is structurally a finite-size mean-field model, and what that costs when the data isn't — with the 2D Ising transition as a clean test case.
Non-interacting particles coupled only by a shared reset event — enough to correlate a gas that would otherwise never meet. Exact results for extremes, gaps, and order statistics follow from conditioning on a single hidden variable.
Dyson Brownian motion of eigenvalues, reset simultaneously. Stationary density, extreme-eigenvalue statistics, and the crossover between repulsion- and reset-dominated regimes.
The conditional-independence assumption baked into every VAE decoder —
pθ(x | z) = Πi p(xi | z) —
is formally equivalent to a finite-size mean-field factorization.
The consequence: a VAE perfectly recovers Curie–Weiss systems, but
structurally fails on genuinely correlated ones. Trained on 2D Ising
samples, it smears out the sharp singularity at
Tc ≈ 2.27. No amount of training recovers it.
Time, privacy, robustness, accuracy: trade-offs for the open vote network protocol
Fatima-Ezzahra El Orche, Rémi Géraud-Stewart, Peter B. Rønne, Gergei Bana, David Naccache, Peter YA Ryan, Marco Biroli, Megi Dervishi, Hugo Waltsburger