Piet Lammers is awarded the Claude-Antoine Peccot prize by Collège de France - IHES
Piet Lammers IHES

Piet Lammers is awarded the Claude-Antoine Peccot prize by Collège de France

Piet Lammers has been awarded the Claude-Antoine Peccot prize by Collège de France and will give a series of Peccot lectures in 2024. This prestigious distinction is reserved for mathematicians under the age of 30 who have made significant contributions to their field. The courses focus on the Peccot Lecturers’ recent work.

Piet Lammers was a postdoctoral researcher at IHES between September 2020 and August 2023, working in collaboration with permanent professor and 2022 Fields medalist Hugo Duminil-Copin, who is also a professor at the University of Geneva.

Starting in September 2023 Lammers will hold a CNRS junior professorship — a tenure-track position recently created by CNRS — at the Laboratoire de Probabilités, Statistique et Modélisation (Sorbonne Université / Université Paris Cité / CNRS).

Over his three years at IHES, Lammers made important contributions to the understanding of the XY model — a variation of the Ising model in which spins can take any direction in the plane. While important progress has recently been made in the understanding of the Ising model, it has been challenging to study the XY model mathematically. This makes this research line particularly interesting.

Piet Lammers’ contributions have recently appeared in a series of three articles [1-3] that advance the understanding of the XY model by establishing new connections with height functions. These are random integer-valued functions on the square lattice, and they constitute his main domain of expertise.

The Peccot Lectures that Piet Lammers will give in 2024 will provide a general overview of this research line and a perspective on its possible developments, while also delving into each one of his three key papers.

“I am very happy to be given this opportunity and I look forward to taking up the challenge of explaining my results to a highly respected audience from a heterogeneous background”, said Piet Lammers when receiving the news of the prize. “Being at IHES and working with Hugo made a profound difference for me. It was incredibly inspirational and gave me the confidence to work on difficult problems — which is an essential quality for doing research in mathematics”, he added.

IHES warmly congratulates Piet on this honor, which recognizes the importance and novelty of his contributions.


Piet Lammers

Piet Lammers did his undergraduate studies in Liberal Arts and Science at University College Utrecht, in the Netherlands, which allowed him to attend courses in different fields, before moving to the University of Cambridge to specialize in mathematics during his postgraduate studies. It is there that he discovered his love for probability theory, which led him to do a PhD under the supervision of Prof. James Norris. During the PhD he started working on height functions and, after a recommendation of Prof. Nathanaël Berestycki (who was at the University of Cambridge at the time) he collaborated with Martin Tassy, then a postdoctoral researcher at Dartmouth College. Piet Lammers spent three years at IHES as a postdoctoral researcher working in collaboration with Hugo Duminil-Copin.


[1] Lammers, P. Height function delocalisation on cubic planar graphs. Probab. Theory Relat. Fields 182, 531–550 (2022). https://doi.org/10.1007/s00440-021-01087-9
[2] Lammers, P. A dichotomy theory for height functions, arXiv:2211.14365
[3] Lammers, P. Bijecting the BKT transition, arXiv:2301.06905

Other references:

[4] https://link.springer.com/article/10.1007/s00220-022-04550-3
[5] https://arxiv.org/abs/2110.09498
[6] Fröhlich J. and Spencer T. The Kosterlitz-Thouless transition in two-dimensional Abelian spin systems and the Coulomb gas, Communications in Mathematical Physics 81 (1981), no. 4, 527–602.


Photo: ©Patrick Imbert (Collège de France)