Antony Garrett Lisi (born January 24, 1968) is an American theoretical physicist whose research focuses on differential geometry, mathematical physics, and quantum gravity. He is known for his 2007 proposal, An Exceptionally Simple Theory of Everything, which sought to unify gravity and the Standard Model of particle physics using the exceptional Lie group E8. The theory has been extensively criticized in the scientific community.
Lisi was born in Los Angeles and raised in San Diego, California. He graduated from Cate School in 1987. Lisi went on to receive two B.S. degrees with highest honors in physics and mathematics from the University of California, Los Angeles, in 1991. Lisi received a Ph.D. in physics from the University of California, San Diego, in 1999. Lisi then left academia.
In July 2006, Lisi was awarded an FQXi grant to conduct research in quantum mechanics and unification. In June 2007, Lisi thought that the algebraic structure he had constructed in an attempt to unify the Standard Model of particle physics with general relativity partially matched part of the algebraic structure of the E8 Lie group. In July 2007.
Lisi's paper, "An Exceptionally Simple Theory of Everything", was posted to the arXiv on 6 November 2007. His theory was discussed on major physics blogs and reported by media sources in several countries. Lisi presented his theory at the TED Conference on 28 February 2008, and has since presented several academic talks and colloquia. The theory has been extensively criticized in the scientific community. Back in 2008, Scientific American stated, "Today the theory is being largely but not entirely ignored".
In July 2009, at a FQXi conference in the Azores, Lisi made a public bet with Frank Wilczek that superparticles would not be detected by 8 July 2015. After a one-year extension to allow for more data collection from the Large Hadron Collider, Frank Wilczek conceded the superparticle bet to Lisi in 2016.
In 2011 and 2012, Lisi co-hosted Invention USA (with Reichart von Wolfsheild), a two-season, reality TV series on the History channel. Lisi was replaced as co-host by Scotty Ziegler in the second season.
Lisi founded the Pacific Science Institute (PSI), an organization established to support independent scientific research and collaboration outside traditional academic institutions. Its first site on Maui was acquired in 2013 and made available to visiting researchers. A second site in Utah was established in 2021.
Lisi has worked as an independent researcher in theoretical physics, focusing on differential geometry and Lie algebras and their applications to gravity and particle physics. His research has explored geometric frameworks for combining general relativity with the Standard Model of particle physics.
His research has been supported by the Foundational Questions Institute (FQXi).
On 8 May 2006, in an arXiv preprint, "Quantum mechanics from a universal action reservoir," Lisi proposed that the path integral formulation of quantum mechanics can be derived from information theory and the existence of a universal action reservoir.
An Exceptionally Simple Theory of Everything
Lisi's main work in theoretical physics is his Exceptionally Simple Theory of Everything. It proposes a unified field theory combining a grand unification theory of particle physics with Albert Einstein's general relativistic description of gravitation, using the largest simple exceptional Lie algebra, E8. Lisi stated that gravity, the Standard Model bosons and fermions can be unified as parts of an E8 superconnection. The theory, called E8 Theory, also predicts the existence of many new particles. He then designed a web application, the Elementary Particle Explorer, for visualizing the charge structure of the elementary particles in the standard model, in grand unified theories, and in E8 Theory.
Lisi's theory has been extensively criticized in the scientific community. Lisi acknowledges that his theory is incomplete. In a Scientific American post, Lisi stated, "(the 3 generation) … issue remains the most significant problem, and until it is solved the theory is not complete and cannot be considered much more than a speculative proposal. Without fully describing how the three generations of fermions work, the theory and all predictions from it remain tenuous."
In June 2010, Lisi posted "An explicit embedding of gravity and the Standard Model in E8", and in 2015 an update and generalization, "Lie group cosmology", in which he claims to have solved the 3 generations problem. The 2015 paper remains unpublished.
In 2015, Lisi proposed a cosmological model based on Lie groups. His paper examined how de Sitter spacetime can be embedded in Lie groups and how deforming Lie group geometry can give rise to a superconnection.
Lisi's later research has focused on triality, a symmetry in certain Lie groups and Clifford algebras. In his 2024 preprint C, P, T, and Triality, he proposed extending charge conjugation, parity and time-reversal symmetries with a triality transformation. He introduced the CPTt group as a mathematical framework for relating the three generations of fermions, developing an idea also present in his earlier work on E8.
Lisi's research has examined the relationships among division algebras, Clifford algebras, spinors, triality, and exceptional Lie algebras. His work focuses on mathematical structures including complex numbers, quaternions, octonions, and related composition algebras to investigate the symmetries and representations underlying theoretical physics. He has studied how these algebras relate to Clifford algebras and their associated symmetry groups, and how triality connects vector and spinor representations.
Algebraic structures in theoretical physics