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Jacob Calvert

I am on the 2025–2026 academic job market! [CV]

I’m a mathematician and data scientist. I’m interested in the relationship between the behavior of individuals and that of the collectives they comprise. Fundamental scientific questions concern the forward direction, such as “How do the properties of tissues emerge from those of cells?” Grand challenges of engineering concern the reverse, like “How should I design an individual robot so that the swarm has desirable collective behavior?” I develop theory and methods to answer questions like these.

Currently, I’m a postdoctoral fellow at Georgia Tech and a visiting postdoctoral fellow at the Santa Fe Institute. I spent Spring 2025 as the Berlekamp postdoctoral fellow at the Simons Laufer Mathematical Sciences Institute. For details on my background and experience as a professional data scientist, see About. For more on my research, check out my Google Scholar profile, Papers, or Posts.

News 🔗

10/2025   SFI announced my visiting position!
09/2025   I attended the Postdocs in Complexity Global Conference during a two-week visit to SFI.
08/2025   I gave a talk in the stochastics seminar at Georgia Tech.
06/2025   Siobhan Roberts wrote an article about my work at SLMath with Frank den Hollander and Dana Randall.
04/2025   I gave a talk in the Stanford probability seminar.
01/2025   I started a Berlekamp Postdoctoral Fellowship at SLMath for the program on the Probability and Statistics of Discrete Structures.
11/2024   I gave a seminar talk at SFI during a two-week visit. Thanks to James Holehouse for the invitation!
10/2024   My work with Dana Randall on a non-equilibrium analogue of the Boltzmann distribution was highlighted by Georgia Tech and Phys.org.

Dynamic clinical risk scores can cheat the AUC

Clinical risk scores can cheat the AUC when the time that an adverse event occurs in a positive-class stay tends to exceed the duration of a negative-class stay. Risk scores should be compared to uniformly random scores that match their timing.

New paper on critical numerosity

My latest paper introduces the concept of critical numerosity: A number of individuals above and below which the behavior of a collective qualitatively differs.

A dichotomy in models of collective motion

This post explains how the Markov chain dichotomy of transience and recurrence implies dichotomous behavior for certain models of collective motion.

A third rigorous result about DLA

This post highlights recent work which constitutes only the third rigorous result about planar diffusion-limited aggregation (DLA), a paradigmatic model of random, dendritic growth.

A conjecture about harmonic measure

Given finite $A \subset \mathbb{Z}^2$, the harmonic measure of $x \in A$ is the probability that a simple random walk “from infinity” first visits $A$ at $x$. If $A$ has $n$ elements, what is the smallest positive harmonic measure that you can get?