The paper demonstrates that the Brown-York tensor—a measure of energy-momentum on spacetime boundaries—naturally emerges from an entropic principle linking gravity to a measure of disorder. The method is uniform for any surfaces, including lightlike ones. Doesn't this resemble a hologram, where the whole bulk world is encoded on the boundary?
Gravity isn’t fundamental—it’s a shadow cast by entropy, the measure of disorder. Back in the 1970s, Jacob Bekenstein and Stephen Hawking found that black holes store disorder on their surface, as if information is smeared across the shell. Now physicists have derived Einstein’s equations—the rules by which mass bends spacetime—from entropy density. The same recipe describes energy at boundaries—like the pressure at a black hole’s edge—even for surfaces zipping along at light speed. Before, the math broke down there; now everything snaps into place: chaos inside births geometry outside. Tests with an extra field, a kind of invisible medium, confirmed that this entropic glue holds universally. In an unexpected twist, at lightlike boundaries, energy behaves like a frictionless fluid—it flows but never loses shape.
🎯 A black hole stores information about its disorder on its surface—as if all data is written on the shell, not inside.