Ted Jacobson & David Mattingly

July 2026

Who they are

Ted Jacobson (b. 1954) is an American theoretical physicist at the University of Maryland, known for foundational work connecting thermodynamics and gravity. Together with David Mattingly, he published “Gravity with a dynamical preferred frame” in Physical Review D in 2001, introducing what’s now called Einstein-aether theory.

What they’re known for on this site

Einstein-Aether Theory is a real, peer-reviewed modified-gravity framework — not PBT’s own invention — that adds a dynamical, timelike unit vector field ($u^\mu$, “the aether”) to general relativity’s spacetime metric. Because this aether is dynamical (it responds to and affects the gravitational field, rather than sitting as a fixed, undetectable background), it can introduce a locally preferred direction without reintroducing the kind of fixed rest frame the Michelson-Morley experiment already ruled out. This is the real, published framework PBT’s own aether field is built on top of.

Catalog status: Unproven Systems At Large

Einstein-aether theory is a legitimate, peer-reviewed research program in modified gravity — real physicists at real institutions have published on it for over two decades — but it remains unconfirmed, and its own coupling constants are tightly squeezed toward zero by real constraints (most significantly GW170817’s gravitational-wave speed measurement).

Mentioned on this site

• Einstein-Aether Theory
• Reference Guide

Where this touches PBT

This is the single most direct real, peer-reviewed foundation for PBT’s own aether-field mathematics — PBT’s papers explicitly build their $u^\mu$ field on Jacobson and Mattingly’s framework, and rely on their published reasoning for why a dynamical aether isn’t pre-refuted by 19th-century aether-drag experiments, rather than offering independent reasoning of their own.