Long-Range Interactions and the Origin of Black Hole Entropy

by Prof. Nicolo Defenu (ETH Zurich)

Monday 15 Jun 2026, 11:30 → 12:30 Asia/Kolkata

AG69 and on Zoom

In our quest to understand the emergence of structure in complex quantum systems, we investigate the thermodynamic properties of a paradigmatic disordered model. The Sachdev–Ye–Kitaev (SYK) model has established itself as a cornerstone framework for probing the quantum nature of black holes, most notably through its finite residual entropy at zero temperature. In this talk, I will present a systematic study of a chain of SYK dots coupled via power-law decaying interactions, and demonstrate how the range of these couplings governs the fate of this residual entropy.

Tuning from the strongly non-local to the local limit, the black-hole phase of the isolated SYK model gives way to a long-range Fermi-liquid regime, which in turn crosses over into a conventional non-Fermi-liquid phase as interactions become short-ranged. These findings establish the interaction range as a natural tuning parameter in black hole thermodynamics and quantum information, and point toward a broader organising principle for non-Fermi-liquid physics in systems with long-range interactions.