Lisi is known for "An Exceptionally Simple Theory of Everything," a paper proposing a unified field theory based on the E8 Lie group, combining particle physics with Einstein's theory of gravitation. The theory is incomplete and not widely accepted by the physics community.
Born in Los Angeles and raised in San Diego, California, Lisi graduated from the Cate School (south of Santa Barbara, California) in 1986. He learned to surf in San Diego, where he traveled between surf breaks in an old VW Bus. 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.
After getting his Ph.D., Lisi left academia and moved to Maui – expressing his dissatisfaction with the state of theoretical physics:
I got my PhD and looked at my options. I love differential geometry, general relativity, and particle physics. But the only options available then for a postdoc in those combined areas were in string theory, and I thought string theory was overly speculative. There are many really impressive aspects of strings – anomaly cancelation in particular – but there are other things that just seem wild and physically unsubstantiated. I had gotten lucky by investing my graduate stipend in a little company many thought was going out of business (AAPL), so I decided to go to Maui, learn to windsurf, and work on physics on my own.
On Maui, Lisi volunteered as a staff member at a local Sudbury school, and split his time between working on his own physics research and surfing.
While living in a customized van with his girlfriend, Crystal Baranyk, Lisi taught physics classes at University of Hawaii – Maui College. After two years on Maui, Lisi says he was offered a tenure track teaching position at the local college, but turned it down (even though he was nearly broke) because it wouldn't have given him enough time for his physics research. At the same time, he submitted a grant application to the newly formed Foundational Questions Institute (FQXi). Lisi says the decision to turn down the job offer and hope for FQXi funding was "a hell of a gamble."
On July 31, 2006, Lisi was awarded an FQXi grant to develop his research in quantum mechanics and unification. The grant allowed Lisi to devote his full attention to physics and create his personal research wiki, Deferential Geometry. On June 9, 2007, Lisi realized that the algebraic structure he had constructed to unify the standard model of particle physics with general relativity partially matched part of the algebraic structure of the E8 Lie group.
On July 21, 2007, Lisi traveled to the inaugural FQXi conference in Reykjavík, Iceland. He was invited to give several academic talks. On invitation from Lee Smolin, Lisi visited the Perimeter Institute for Theoretical Physics in October, and posted his paper, "An Exceptionally Simple Theory of Everything," to the arXiv on November 6, 2007. Discussions of Lisi's theory developed rapidly over most major physics blogs, and the story of Lisi's theory and personal history was reported by many online and traditional media sources around the world.
Lisi presented at the TED Conference on February 28, 2008, and has since presented several academic talks and colloquia.
On July 8, 2009, at a FQXi conference in the Azores, Lisi made a public bet with Frank Wilczek that superparticles would not be detected by July 8, 2015.
In July 2010, mathematicians and physicists met with Lisi at the Banff International Research Station in Alberta, Canada, for a week to discuss his theory.
On Aug 16, 2016, after a one-year extension to allow for more data collection from the Large Hadron Collider, Frank Wilczek conceded the superparticle bet to Lisi.
On May 8, 2006, in an arXiv preprint, "Quantum mechanics from a universal action reservoir," Lisi proposes that the path integral formulation of quantum mechanics can be derived from information theory and the existence of a universal action reservoir.
Lisi is an early practitioner of open notebook science. Lisi created his "personal wiki notebook in theoretical physics" – the Deferential Geometry website – by using TiddlyWiki and jsMath. Lisi uses this wiki to organize his research notes in theoretical physics, referring to this as "open source physics."
Lisi's main work in theoretical physics is his Exceptionally Simple Theory of Everything, which 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. In a paper posted to the physics arXiv on November 6, 2007, and in a popular article published in Scientific American in December, 2010, Lisi describes his proposal that gravity, the standard model bosons and fermions can be unified as parts of an E8 superconnection. This unified field theory attempts to describe all fundamental interactions observed in nature, as a possible theory of everything, unifying Albert Einstein's general relativity with the standard model of particle physics. The theory, called E8 Theory, also predicts the existence of many new particles.
Lisi 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 applauded but also criticized in the scientific community. He has addressed the criticism, while acknowledging that the theory is incomplete. In a Scientific American post, Lisi himself 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.
Since then, he continues working on the theory. 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."
Garrett Lisi is an adventure sports enthusiast – surfing, snowboarding, and kitesurfing at the expert level as well as participating in many other adventure sports. In an interview for Wired News, Lisi says:
Surfing and snowboarding are what I do for fun – to get out and play in nature. We live in a beautiful universe, and I wish to enjoy it and understand it as best I can. And I try to live a balanced life. Surfing is simply the most fun I know how to have on this planet. And physics, and science in general, is the best way of understanding how everything works. So this is what I spend my time doing. I do what I love, and follow my interests. Shouldn't everyone?
Lisi brings some of his physics to his sports activities. During graduate school and years in Maui, most of Lisi's surfboards were adorned with the wave equation as decorative art. And when riding an extra-long carving board, for alpine snowboarding, in Colorado and Tahoe, Lisi always wears a long white lab coat. He has also become a sponsored team rider for an Oregon surfboard manufacturer, 42 Surfboards.
Although concentrating on surfing, kitesurfing and snowboarding, Lisi participates in a wide variety of adventure sports. On his online journal, Lisi describes his experiences surfing, snowboarding, windsurfing, sailing, kitesurfing, mountain biking, skateboarding, motorcycling, cliff diving, rock climbing, hang gliding, paragliding, backpacking, water skiing, wakeboarding, flying, sky diving, and scuba diving. Lisi is working on a film about young scientists who combine cutting-edge research with adventure sports.
In 2011 and 2012, Lisi co-hosted (with Reichart Von Wolfsheild) Invention USA, a History channel documentary television series.
Lisi proposes the creation of a more casual kind of science institute – a science hostel – which he says "would essentially be large houses in beautiful locations where theorists could live and work." Citing his experience living in Maui and the mountains of Tahoe and Colorado, Lisi says that for theoretical research it is good to have opportunities for hiking and things to do outside in attractive environments. Describing the idea more formally, Lisi says:
The physical requirements for conducting scholarly research have changed dramatically with the rise of the internet. It is now viable for researchers with laptop computers to work autonomously – with access to current articles and communication channels on par with the resources available at large universities. These new circumstances motivate the creation of a new kind of research enterprise: a Science Hostel. By providing places to live and work with other researchers, in beautiful locations, a Science Hostel could increase creative productivity and overall quality of life for scholars in the internet age.
In 2014 Lisi founded the Pacific Science Institute as the first science hostel.