ICM 2026 Invited Section Lecture - Tom Hutchcroft

ICM 2026 Invited Section Lecture - Tom Hutchcroft

🎙 Tom Hutchcroft 👥 60K 📅 September 21, 2026 ⏱ 44 min 👁 8 📄 literature review 🧭 2026-09-21
Available in: English (current) Français

Keywords

percolationcritical exponentsupper critical dimensionbranching random walklong-range

Summary

The speaker, Tom Hutchcroft, gives an invited lecture at ICM 2026 reviewing critical long-range percolation. He starts by introducing phase transitions and critical phenomena, emphasizing universality and the role of dimension. After defining percolation on the hypercubic lattice, he discusses the critical probability and the conjecture about cluster existence at criticality. He then focuses on quantitative aspects, introducing critical exponents and the concept of upper critical dimension, which for percolation is six. He compares percolation to branching random walk, illustrating with animations that in high dimensions (≥7) percolation exhibits mean-field behavior, as proven by Hara and Slade under certain conditions. In two dimensions, exact rational exponents are known via conformal field theory, while in six dimensions logarithmic corrections are conjectured. He also discusses the structure of large critical clusters, which are tree-like in high dimensions and converge to the continuum random tree. Finally, he introduces long-range percolation with power-law distributions, highlighting its richer phase diagram and the existence of phase transitions even in one dimension.

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Critical Evaluation

Value of the Information & Strength of the Argument

The talk provides a high-value synthesis of a complex topic, connecting rigorous results with physical intuition. The argumentation is well-structured: he uses clear analogies (e.g., comparing percolation to branching random walk) and visual aids to illustrate dimensional dependence. He carefully distinguishes established theorems from conjectures, and outlines the historical development and current frontiers, enhancing credibility.

Scientific Rigor, Source Quality, Title Accuracy

The scientific rigor is strong: the speaker cites key works by Kesten, Harris, Hara and Slade, Fitzner, and others, and accurately reports the current state of proofs and open problems. The title is faithful to the content—an invited lecture on long-range percolation. No comments were provided, so no public reception analysis is included.

123 words

Title / Content Match

The title accurately reflects the format (invited lecture) and the speaker, while the content focuses on critical long-range percolation, matching expectations.

Quality & Reliability

9/10

The lecture is an expert review by a leading probabilist, presenting well-established results and recent progress with appropriate rigor.

Key Moments

Cited Sources

  • Kesten, H. (1980). The critical probability of bond percolation on the square lattice equals 1/2 — Mentioned as the theorem determining the exact critical probability for square lattice percolation.
  • Harris, T. E. (1960). A lower bound for the critical probability in a certain percolation process — Referenced in the context of proving absence of infinite clusters at criticality in two dimensions.
  • Hara, T. & Slade, G. (1990). Mean-field critical behaviour for percolation in high dimensions — Cited as proving mean-field critical exponents for percolation in dimensions d≥7 under certain conditions.
  • Fitzner, R. & van der Hofstad, R. (work on hypercubic lattice) — Mentioned as improving the bound to d≥11 for the standard hypercubic lattice.
  • Aizenman, M. (1986) - study of scaling limits and number of clusters — Referenced regarding the polynomial number of macroscopic clusters in high dimensions.
  • Aldous, D. - construction of continuum random tree — Mentioned as the scaling limit for critical clusters in high dimensions.
  • Bauerschmidt, R., Brydges, D., & Slade, G. - work on self-avoiding walk — Cited as an example where renormalization group arguments were made rigorous.
  • Newman, C. M. & Schulman, L. S. (1986) - one-dimensional long-range percolation — Mentioned for proving phase transitions in one-dimensional long-range percolation.
  • S. M. ... (physicist) and Gutmann, A. - conjectures for six-dimensional percolation — Cited for non-rigorous derivations of logarithmic corrections at the upper critical dimension.

Contribution & Novelties

The talk does not present new original research but offers a clear, up-to-date synthesis of the field, highlighting recent breakthroughs such as the convergence of critical clusters to the continuum random tree and the latest results on the mean-field regime. Its value lies in clarifying the dimensional-dependent behavior and the open problems, especially in dimensions 3–6.

Pour aller plus loin :

  • Percolation theory — Provides a broad overview of the model and its history.
  • Upper critical dimension — Explains the concept with examples and relevance to this topic.
  • Branching random walk — The reference model used for comparison with percolation.
  • Continuum random tree — Discusses scaling limits of random trees, relevant to the cluster structure.

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Radar Profile

The radar profile shows a high level of technical depth and reliability, with slightly lower scores on quantity, reflecting a focused review rather than an exhaustive survey. Overall, the content is rigorous and well-supported.

Reliability 9/10