Interacting stochastic systems
From microscopic randomness to macroscopic laws — in particles,
spins, markets, and AI agents.
I study how many interacting random or imperfect components produce
reliable collective behaviour. My tools come from probability,
statistical mechanics, optimal transport, PDE, and data-driven
computation.
Short CV (PDF)
Google Scholar
AGRADE
Contact
About
I joined UCLA's Department of Mathematics in January 2016. Before
that I held postdoctoral positions at the Max Planck Institute for
Mathematics in the Sciences in Leipzig, Stanford University, and
the Simons Laufer Mathematical Sciences Institute (SLMath, formerly
MSRI). I did my PhD with Felix Otto.
The common theme in my work is interaction. Many simple
objects — particles, spins, random height functions, market orders —
can produce surprisingly stable macroscopic behaviour, and I try to
understand when this happens, how fast it happens, and how robust
the resulting laws are: a noisy microscopic system, on the right
scale, behaves like the solution of a heat equation; random height
functions concentrate on predictable limit shapes; the trades of
many small agents aggregate into a market price.
Lately the same theme has pulled me into AI for mathematics. With
my student Maciej Głuchowski I developed
AGRADE, an automated, multi-agent AI grading tool currently piloted in
the UCLA Mathematics Department. A network of language models,
structured to critique and repair one another, can be far more
reliable than any one of them on its own — which is, in a different
language, the same question that drives much of my mathematical
work: how does reliable macroscopic behaviour emerge from many
unreliable interacting parts?
Current PhD students.
Edward Athaide,
Maciej Głuchowski.
Former PhD students.
Tianqi Wu, Andrew Krieger, Younghak Kwon.