Physicists Discover First Non-Relativistic Black Hole Without Light Limits

Physicists have constructed the first mathematical black hole solution within a strictly non-relativistic gravitational framework, completely bypassing traditional speed-of-light limitations. The discovery points to a new way of understanding thermodynamic behavior in spacetimes where standard Einstein-style relativity does not apply.

How Non-Relativistic Gravity Shapes Spacetime Geometry

Traditional black holes rely heavily on the geometry of Einstein gravity, where a finite speed of light creates a strict boundary known as an event horizon. In non-relativistic physics, however, light cones open up completely and shatter standard relativistic notions of causality. To explore whether black hole thermodynamics could exist without an underlying Lorentzian geometry, a team of researchers investigated three-dimensional Galilean Anti-de Sitter gravity, a theory available published on the arXiv preprint server in November 2026. Authored by Luis Avilés, Oscar Fuentealba, Diego Hidalgo, and Pablo Rodríguez, the study formulates the gravitational system as a topological gauge theory invariant under the doubly extended Newton-Hooke group in three spacetime dimensions.

Because a conventional metric horizon ceases to be a meaningful physical concept in this regime, the authors adopted an alternative gauge-theoretic characterization. They imposed a trivial holonomy condition along the contractible thermal cycle of the Euclidean continuation of the solution. This technical requirement ensures that thermal properties remain well-defined without needing a traditional event horizon.

Four Conserved Charges and an Unexpected Spin Bound

The resulting spacetime configuration features four distinct conserved charges governing its physical state: energy, angular momentum, spin, and rest mass. A striking feature of the mathematical solution is a strict constraint linking the intrinsic spin to the rest mass. Specifically, the authors report that the magnitude of the spin is bounded from above by the rest mass, expressed mathematically as the condition where the absolute value of the spin cannot exceed the product of the AdS radius and the rest mass.

When this upper bound is completely saturated, the system transitions into an extreme configuration characterized by a vanishing temperature. Under this zero-temperature regime, the topology of the solution shifts, and the magnitude of the angular momentum ultimately equates to the total energy of the configuration.

Testing the Laws of Thermodynamics Without Light Limits

To verify whether the system truly behaves like a thermodynamic black hole, the research team calculated the associated entropy using a specialized Chern-Simons formula. By evaluating the intensive quantities, including temperature, angular velocity, and the chemical potentials linked to the rest mass and spin charges, the authors checked the validity of the fundamental laws of physics in this exotic setting.

The analysis demonstrates that the first law of thermodynamics holds perfectly within the micro-canonical ensemble for this Galilean black hole. Furthermore, an asymptotic symmetry analysis reveals that the underlying symmetries of the theory expand into an infinite-dimensional structure analogous to an extended Maxwell algebra.

What Questions Remain Open for Galilean Holography?

While the work successfully establishes a concrete thermodynamic solution in non-relativistic gravity, several important theoretical questions remain. The authors note that it would be valuable to investigate whether this non-relativistic black hole admits a standard relativistic parent geometry from which it can be derived through a specific limit. Future studies are also expected to explore whether these asymptotic symmetries support a non-relativistic analog of the famous Cardy formula, potentially paving the way for new applications in non-relativistic holography and condensed matter systems.

The study was posted to the arXiv preprint server on November 5, 2026.