High-temperature free-energy fluctuations in the SYK model

The Gaussian q-body Sachdev–Ye–Kitaev (SYK) model describes randomly interacting Majorana fermions. For fixed even q≥4, what is the limiting distribution of N^(q/2−1)(log Z_N−E log Z_N), where Z_N is the partition function? The target takes even N to infinity at a fixed, sufficiently small positive inverse temperature.

Why it matters and what counts as progress

Why it matters: The fluctuation law describes sample-to-sample variation beyond the average free energy in a quantum-disorder model studied in statistical physics and holography.

What counts as progress: Establish the limiting distribution, its nonzero variance and a valid high-temperature range under the stated normalization. A result in this regime does not establish the low-temperature behavior.

How the problem developed

  1. 4 May 2026 · Free energy limit [1]

    David Gamarnik, Francisco Pernice, Alexander Schmidhuber and Alexander Zlokapa Reported rigorous annealed and quenched free-energy limits for the SYK model at sufficiently high but constant temperature.

  2. 13 Oct 2026 · Central limit theorem [2]

    Yoshinori Kamijima, Shuta Nakajima, Ryoichiro Noda and Kôhei Sasaya Proved a high-temperature central limit theorem for centered log partition functions in the Gaussian q-body SYK model, for fixed even q≥4 and sufficiently small inverse temperature; the paper describes Lean formalization of the main arguments.

AI contribution

Sources

  1. Gamarnik, Pernice, Schmidhuber and Zlokapa, The free energy limit of the SYK model at high temperature
  2. Original paper v1: statement, prior work and AI contribution
  3. Full manuscript and limitations
  4. Authors’ Lean development, conditional on Proposition 4.2
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