A theory of everything | Garrett Lisi

Summary

In this engaging talk, the speaker explores the elegance of particle physics, drawing a parallel between the branching nature of coral and quantum mechanics' concept of reality branching into multiple possibilities. Without delving into complex equations, the presentation dives into the Large Hadron Collider's role in particle discovery and introduces the audience to the fundamental particles and forces that govern our universe. The speaker then presents a unifying theory, suggesting that the known patterns of elementary particles could emerge from a more symmetrical structure, potentially encapsulated by the E8 Lie group, a complex geometric shape with deep mathematical roots. The idea that this mathematical beauty could underpin the fabric of the universe is both fascinating and humbling.

Takeaways

• 🌊 The presenter likens the branching nature of coral to the concept of quantum mechanics, suggesting that reality branches into different possibilities, much like the polyps of a coral.
• 🧬 The script explains the fundamental particles and forces in the universe, emphasizing the importance of balance in their interactions and how they relate to geometric patterns.
• 🔬 The Large Hadron Collider (LHC) at CERN is highlighted as a tool for exploring these subatomic particles, with its capabilities to accelerate protons and antiprotons to near light speed for collision experiments.
• 🌐 The concept of 'Everything that can happen, does' is attributed to quantum mechanics, illustrating the probabilistic nature of reality at the quantum level.
• 🤔 The script ponders the existence of the Higgs particle, which is believed to give mass to other particles, and its significance in the search for a unified theory of physics.
• 🔍 The presentation delves into the idea of unification in particle physics, suggesting that the known pattern of charges could emerge from a more symmetric pattern, hinting at the possibility of undiscovered particles.
• 🌀 The E8 Lie group, an 8-dimensional geometric structure, is introduced as a potential framework for unifying all known particles and forces, including gravity, into a single, coherent model.
• 🔮 The potential of the E8 model to predict new particles is discussed, with the LHC's role in either confirming or refuting this theory through experimental evidence.
• 🏄‍♂️ The presenter shares a personal anecdote about living a balanced life, emphasizing the importance of pursuing passions and maintaining a harmonious work-life balance.
• 🌴 The beauty of the natural world, particularly the island of Maui, is used as a metaphor for the beauty found in mathematical descriptions of the universe.
• 🎲 The risks and uncertainties inherent in theoretical physics are acknowledged, drawing parallels to the unpredictable nature of start-up companies and the need for resilience in the face of failure.

Q & A

What is the main theme of the speaker's talk about particle physics?

The main theme is to describe the beauty of particle physics without equations, using the analogy of a hyperintelligent coral to explain complex concepts like quantum mechanics and the potential underlying geometric structures of the universe, such as E8.

How does the speaker use coral as an analogy to explain quantum mechanics?

The speaker compares the branching of coral polyps, which are genetically identical, to the concept of reality branching into different possibilities in quantum mechanics, illustrating how each branch is experienced separately, much like how we experience only one reality among many possible ones.

What is the significance of the Large Hadron Collider (LHC) mentioned in the script?

The LHC is significant as it is a particle accelerator used to study the fundamental particles of the universe. It allows scientists to observe high-energy collisions of protons and antiprotons, which can result in the creation of new particles and provide insights into the fundamental forces and symmetries of nature.

What is the concept of 'everything that can happen, does' in the context of quantum mechanics?

This concept reflects the idea that at the quantum level, all possible outcomes of a quantum event are realized in some branch of reality, according to the mathematics of quantum mechanics.

How does the speaker describe the unification of forces in terms of particle charges?

The speaker describes the unification of forces by plotting the charges of particles in multi-dimensional charge spaces. For example, the electroweak model unifies the electromagnetic and weak forces based on hypercharge and weak charge, while the strong force is represented by color charge.

What is the role of the Higgs particle in the context of the electroweak model?

The Higgs particle is responsible for giving mass to other particles, which breaks the symmetry of the electroweak model and makes the weak force appear weak. It also keeps the photons of electromagnetism massless.

What is the significance of the E8 Lie group in the speaker's theory?

The E8 Lie group represents a highly symmetrical geometric structure that could potentially describe all known elementary particles and their interactions. It is considered a candidate for a theory of everything, unifying all fundamental forces and particles.

How does the speaker relate the E8 pattern to the particles we observe?

The speaker suggests that the E8 pattern could be the underlying structure of space-time, with the symmetries of the E8 shape corresponding to the particles we observe. The way the shape twists as it moves over space-time would determine the type of particle manifested.

What is the speaker's personal approach to balancing life with the uncertainty of theoretical physics research?

The speaker balances life by dividing it equally among physics, love, and surfing, which are his three 'charge directions.' This approach allows him to maintain happiness and sanity, regardless of the outcomes of his research.

What is the speaker's view on the relationship between mathematics and the natural world?

The speaker believes that nature is inherently mathematical, as stated by Galileo, and that the most beautiful mathematical structures, such as E8, could potentially describe the fundamental interactions of the universe at the smallest scales.

How does the speaker describe the process of discovery in theoretical physics?

The speaker describes the process as an adventure with risks and uncertainties, similar to investing in start-up companies. Theoretical physicists develop ideas knowing that most will not hold true for nature, but the pursuit of understanding is still deeply rewarding.

Outlines

00:00

🌊 The Coral Metaphor for Quantum Mechanics

The speaker begins with a light-hearted introduction, using the coral as a metaphor to explain the complex concept of quantum mechanics. They describe corals as hyperintelligent beings that naturally understand the idea of branching realities, similar to how quantum mechanics describes the universe as continually branching into different possibilities. The famous Schrödinger's cat thought experiment is humorously referenced to illustrate this quantum phenomenon, where the cat is both alive and dead in separate realities. The speaker emphasizes the difficulty humans have in grasping this concept due to our experience of a singular reality, setting the stage for a deeper dive into particle physics without equations.

05:01

🔬 The Geometry of Particle Physics

The speaker transitions into discussing the Large Hadron Collider (LHC) at CERN and its role in understanding subatomic particles. They explain how protons and antiprotons are accelerated and collide, producing energy that transforms into various particles. The LHC's immense scale and power consumption are highlighted to emphasize the grandeur of the scientific endeavor. The talk then delves into the known particles, such as electrons, neutrinos, up and down quarks, and their antiparticles, detailing their properties and roles in the atomic structure. The speaker introduces the concept that physics is about understanding what can and cannot happen based on the balance of interactions between elementary particles.

10:01

🌐 The Unified Electroweak Model and Beyond

The speaker explores the unified electroweak model, which combines the electromagnetic and weak forces, and explains how the Higgs particle gives mass to other particles, affecting the symmetry of the model. They describe the strong force and gravity, each associated with different kinds of charges, and how these forces interact with matter. The speaker then presents the idea that all known particles and their interactions can be visualized in a multi-dimensional charge space, revealing patterns that indicate the allowed interactions. The possibility of new particles and forces that could fit into this pattern is introduced, hinting at the potential for expanding our understanding of the universe.

15:04

🌌 The E8 Theory and the Search for a Grand Unified Model

The speaker introduces the E8 theory, a geometric model that could potentially unify all known forces and particles into a single framework. They discuss the idea of using higher dimensions to create a more symmetric pattern that includes the known particle physics as a subset, allowing for the prediction of new particles. The speaker explains how the E8 pattern, part of a larger exceptional Lie group, could describe the fabric of the universe, including gravity and quantum mechanics. They acknowledge the risks and uncertainties of theoretical physics, likening it to a start-up company where not all ventures succeed, but the pursuit of knowledge is a thrilling adventure.

20:07

🏄‍♂️ Balancing Life, Love, and Physics

In the final paragraph, the speaker reflects on the personal side of being a theoretical physicist, emphasizing the importance of balance in life. They share their own lifestyle choices, living a nomadic existence on the island of Maui, which allowed them to focus on their passion for physics, love, and surfing. The speaker humorously acknowledges the challenges and the beauty of their unconventional life, expressing gratitude for the opportunity to share their ideas at TED. The conversation concludes with a Q&A session where the speaker attempts to clarify the E8 theory and its implications for understanding the fundamental nature of the universe.

Keywords

💡Particle Physics

Particle physics is a branch of physics that studies the elementary particles and forces that make up the universe. It is the main theme of the video, as the speaker attempts to describe the beauty of this field without using equations. The video discusses how particle physics uses mathematical models to understand the fundamental nature of reality, including the behavior of subatomic particles and the forces that govern them.

💡Quantum Mechanics

Quantum mechanics is the physics theory that describes the behavior of particles at the smallest scales of energy levels. It is a key concept in the video, as it introduces the idea of reality branching into different possibilities, akin to the branching of a coral. The speaker uses the famous Schrödinger's cat thought experiment to illustrate the quantum mechanical concept of superposition, where a particle can exist in multiple states simultaneously.

💡Coral

In the video, coral serves as an analogy to explain the concept of quantum mechanics. Each coral head is made up of genetically identical polyps that bud and branch out, similar to how quantum mechanics describes reality branching into different possibilities. The speaker uses this analogy to help the audience grasp the idea of multiple realities existing in parallel.

💡Elementary Particles

Elementary particles are the fundamental constituents of matter that cannot be broken down into smaller components. The video discusses various types of elementary particles, such as electrons, neutrinos, quarks, and their antiparticles. These particles and their interactions are central to understanding the physical universe at the most basic level.

💡Large Hadron Collider (LHC)

The Large Hadron Collider is the world's largest and most powerful particle accelerator, used to study the smallest known particles. In the video, the LHC is mentioned as a tool for physicists to explore the properties of subatomic particles by accelerating protons and antiprotons to nearly the speed of light and observing the resulting collisions.

💡Higgs Particle

The Higgs particle, also known as the Higgs boson, is a fundamental particle in the Standard Model of particle physics, which is believed to give other particles mass. The video mentions the Higgs particle as a crucial element in understanding why some particles have mass and others do not, and the LHC's role in potentially discovering this particle.

💡E8

E8 refers to the largest of the five exceptional Lie groups in mathematics, which are continuous transformation groups. In the video, the speaker suggests that the pattern of elementary particles and their interactions could be described by the geometry of the E8 Lie group. This idea proposes a deep connection between the fundamental structure of the universe and a beautiful mathematical object.

💡Unified Electroweak Model

The unified electroweak model is a part of the Standard Model of particle physics that unifies the electromagnetic and weak nuclear forces into a single force under certain conditions. The video explains how the Higgs mechanism breaks the symmetry of this model, giving rise to the distinct characteristics of these two forces in our everyday experience.

💡Charge Space

In the context of the video, charge space is a conceptual framework used to represent the different types of charges that particles can have, such as electric charge, weak charge, and color charge. The speaker uses this concept to describe how particles interact with each other through various forces, and how these interactions are balanced in terms of charge.

💡Symmetry Breaking

Symmetry breaking is a concept in physics where a system transitions from a symmetric state to a less symmetric one. In the video, the speaker discusses how the Higgs particle causes symmetry breaking in the electroweak model, leading to the differentiation between the electromagnetic and weak forces. The idea is also extended to the possibility of a more symmetric underlying structure that could explain the known particle physics as a broken symmetry.

💡Galileo

Galileo Galilei, an Italian astronomer, physicist, and engineer, is mentioned in the video for his famous quote about the 'book of nature' being written in the language of mathematics. The speaker uses this quote to emphasize the belief that mathematics is the key to understanding the fundamental laws of the universe, a belief that drives the search for a theory of everything, such as the E8 model discussed in the video.

Highlights

The speaker aims to describe the beauty of particle physics without equations, using the analogy of a hyperintelligent coral to explain quantum mechanics.

Coral polyps are used as a metaphor to illustrate the concept of quantum branching, where reality continually branches into different possibilities.

Erwin Schrödinger's cat paradox is introduced to explain the quantum mechanics principle that everything that can happen, does, in some branch of reality.

The Large Hadron Collider (LHC) at CERN is described as a tool for exploring subatomic particles through high-energy collisions.

The LHC's operation consumes five times the power of Monterey city, emphasizing the scale of the scientific endeavor.

The speaker discusses the known subatomic particles, including electrons, neutrinos, up and down quarks, and their antiparticles.

The fundamental forces of nature are outlined: electromagnetic, weak, strong, and gravity, each with its associated particles and charges.

The Higgs particle, responsible for giving mass to other particles, is highlighted as a key objective of LHC research.

The concept of unified electroweak model is introduced, showing the relationship between electric charge, hypercharge, and weak charge.

The speaker presents the idea that the known pattern of charges could emerge from a more symmetric pattern, suggesting the existence of new forces and particles.

The E8 Lie group, a complex geometric structure, is proposed as a potential framework for unifying all known particles and forces.

The E8 pattern is described as having gaps that correspond to the possible existence of new particles, expanding our understanding of particle physics.

Galileo's quote about the 'book of nature' being written in the language of mathematics is used to emphasize the role of math in understanding the universe.

The speaker's personal journey of living a balanced life between physics, love, and surfing is shared, illustrating the importance of balance in the pursuit of knowledge.

The speaker's nomadic lifestyle and the beauty of living on Maui are mentioned, showing the connection between personal fulfillment and scientific pursuit.

The Q&A session with Chris Anderson explores the implications of the E8 theory for understanding the fundamental nature of the universe.

Transcripts

Whoa, dude.

(Laughter)

Check out those killer equations. Sweet.

Actually, for the next 18 minutes I'm going to do the best I can

to describe the beauty of particle physics without equations.

It turns out there's a lot we can learn from coral.

A coral is a very beautiful and unusual animal.

Each coral head consists of thousands of individual polyps.

These polyps are continually budding and branching

into genetically identical neighbors.

If we imagine this to be a hyperintelligent coral,

we can single out an individual and ask him a reasonable question.

We can ask how exactly he got to be in this particular location

compared to his neighbors --

if it was just chance, or destiny, or what?

Now, after admonishing us for turning the temperature up too high,

he would tell us that our question was completely stupid.

These corals can be kind of mean, you see,

and I have surfing scars to prove that.

But this polyp would continue and tell us

that his neighbors were quite clearly identical copies of him.

That he was in all these other locations as well,

but experiencing them as separate individuals.

For a coral, branching into different copies

is the most natural thing in the world.

Unlike us, a hyperintelligent coral

would be uniquely prepared to understand quantum mechanics.

The mathematics of quantum mechanics

very accurately describes how our universe works.

And it tells us our reality is continually branching into different possibilities,

just like a coral.

It's a weird thing for us humans to wrap our minds around,

since we only ever get to experience one possibility.

This quantum weirdness was first described

by Erwin Schrödinger and his cat.

The cat likes this version better.

(Laughter)

In this setup, Schrödinger is in a box with a radioactive sample

that, by the laws of quantum mechanics, branches into a state

in which it is radiated and a state in which it is not.

(Laughter)

In the branch in which the sample radiates,

it sets off a trigger that releases poison and Schrödinger is dead.

But in the other branch of reality, he remains alive.

These realities are experienced separately by each individual.

As far as either can tell, the other one doesn't exist.

This seems weird to us,

because each of us only experiences an individual existence,

and we don't get to see other branches.

It's as if each of us, like Schrödinger here,

are a kind of coral branching into different possibilities.

The mathematics of quantum mechanics tells us

this is how the world works at tiny scales.

It can be summed up in a single sentence:

Everything that can happen, does.

That's quantum mechanics.

But this does not mean everything happens.

The rest of physics is about describing what can happen and what can't.

What physics tells us is that everything comes down to geometry

and the interactions of elementary particles.

And things can happen only if these interactions are perfectly balanced.

Now I'll go ahead and describe how we know about these particles,

what they are and how this balance works.

In this machine, a beam of protons and antiprotons

are accelerated to near the speed of light

and brought together in a collision, producing a burst of pure energy.

This energy is immediately converted into a spray of subatomic particles,

with detectors and computers used to figure out their properties.

This enormous machine --

the Large Hadron Collider at CERN in Geneva --

has a circumference of 17 miles and, when it's operating,

draws five times as much power as the city of Monterey.

We can't predict specifically

what particles will be produced in any individual collision.

Quantum mechanics tells us all possibilities are realized.

But physics does tell us what particles can be produced.

These particles must have just as much mass and energy

as is carried in by the proton and antiproton.

Any particles more massive than this energy limit aren't produced,

and remain invisible to us.

This is why this new particle accelerator is so exciting.

It's going to push this energy limit seven times

beyond what's ever been done before,

so we're going to get to see some new particles very soon.

But before talking about what we might see,

let me describe the particles we already know of.

There's a whole zoo of subatomic particles.

Most of us are familiar with electrons.

A lot of people in this room make a good living pushing them around.

(Laughter)

But the electron also has a neutral partner called the neutrino,

with no electric charge and a very tiny mass.

In contrast, the up and down quarks have very large masses,

and combine in threes to make the protons and neutrons inside atoms.

All of these matter particles come in left- and right-handed varieties,

and have antiparticle partners that carry opposite charges.

These familiar particles

also have less familiar second and third generations,

which have the same charges as the first but have much higher masses.

These matter particles all interact with the various force particles.

The electromagnetic force interacts with electrically charged matter

via particles called photons.

There is also a very weak force

called, rather unimaginatively, the weak force ...

(Laughter)

that interacts only with left-handed matter.

The strong force acts between quarks

which carry a different kind of charge, called color charge,

and come in three different varieties: red, green and blue.

You can blame Murray Gell-Mann for these names -- they're his fault.

Finally, there's the force of gravity,

which interacts with matter via its mass and spin.

The most important thing to understand here

is that there's a different kind of charge associated with each of these forces.

These four different forces interact with matter

according to the corresponding charges that each particle has.

A particle that hasn't been seen yet, but we're pretty sure exists,

is the Higgs particle, which gives masses to all these other particles.

The main purpose of the Large Hadron Collider

is to see this Higgs particle, and we're almost certain it will.

But the greatest mystery is what else we might see.

And I'm going to show you one beautiful possibility

towards the end of this talk.

Now, if we count up all these different particles

using their various spins and charges,

there are 226.

That's a lot of particles to keep track of.

And it seems strange

that nature would have so many elementary particles.

But if we plot them out according to their charges,

some beautiful patterns emerge.

The most familiar charge is electric charge.

Electrons have an electric charge,

a negative one,

and quarks have electric charges in thirds.

So when two up quarks and a down quark are combined to make a proton,

it has a total electric charge of plus one.

These particles also have antiparticles, which have opposite charges.

Now, it turns out the electric charge

is actually a combination of two other charges:

hypercharge and weak charge.

If we spread out the hypercharge and weak charge

and plot the charges of particles in this two-dimensional charge space,

the electric charge is where these particles sit

along the vertical direction.

The electromagnetic and weak forces interact with matter

according to their hypercharge and weak charge,

which make this pattern.

This is called the unified electroweak model,

and it was put together back in 1967.

The reason most of us are only familiar with electric charge

and not both of these is because of the Higgs particle.

The Higgs, over here on the left, has a large mass

and breaks the symmetry of this electroweak pattern.

It makes the weak force very weak by giving the weak particles a large mass.

Since this massive Higgs sits along the horizontal direction in this diagram,

the photons of electromagnetism remain massless

and interact with electric charge along the vertical direction

in this charge space.

So the electromagnetic and weak forces

are described by this pattern of particle charges

in two-dimensional space.

We can include the strong force by spreading out its two charge directions

and plotting the charges of the force particles in quarks

along these directions.

The charges of all known particles

can be plotted in a four-dimensional charge space,

and projected down to two dimensions like this so we can see them.

Whenever particles interact, nature keeps things in a perfect balance

along all four of these charge directions.

If a particle and an antiparticle collide,

it creates a burst of energy and a total charge of zero

in all four charge directions.

At this point, anything can be created

as long as it has the same energy and maintains a total charge of zero.

For example, this weak force particle and its antiparticle

can be created in a collision.

In further interactions, the charges must always balance.

One of the weak particles could decay into an electron and an antineutrino,

and these three still add to zero total charge.

Nature always keeps a perfect balance.

So these patterns of charges are not just pretty.

They tell us what interactions are allowed to happen.

And we can rotate this charge space in four dimensions

to get a better look at the strong interaction,

which has this nice hexagonal symmetry.

In a strong interaction, a strong force particle,

such as this one,

interacts with a colored quark, such as this green one,

to give a quark with a different color charge -- this red one.

And strong interactions are happening millions of times

each second in every atom of our bodies,

holding the atomic nuclei together.

But these four charges corresponding to three forces

are not the end of the story.

We can also include two more charges corresponding to the gravitational force.

When we include these,

each matter particle has two different spin charges,

spin-up and spin-down.

So they all split and give a nice pattern in six-dimensional charge space.

We can rotate this pattern in six dimensions

and see that it's quite pretty.

Right now, this pattern matches our best current knowledge

of how nature is built at the tiny scales of these elementary particles.

This is what we know for certain.

Some of these particles are at the very limit

of what we've been able to reach with experiments.

From this pattern

we already know the particle physics of these tiny scales --

the way the universe works at these tiny scales is very beautiful.

But now I'm going to discuss some new and old ideas

about things we don't know yet.

We want to expand this pattern using mathematics alone,

and see if we can get our hands on the whole enchilada.

We want to find all the particles and forces

that make a complete picture of our universe.

And we want to use this picture to predict new particles

that we'll see when experiments reach higher energies.

So there's an old idea in particle physics

that this known pattern of charges,

which is not very symmetric,

could emerge from a more perfect pattern that gets broken --

similar to how the Higgs particle breaks the electroweak pattern

to give electromagnetism.

In order to do this, we need to introduce new forces

with new charge directions.

When we introduce a new direction,

we get to guess what charges the particles have along this direction,

and then we can rotate it in with the others.

If we guess wisely, we can construct the standard charges

in six charge dimensions as a broken symmetry

of this more perfect pattern in seven charge dimensions.

This particular choice corresponds to a grand unified theory

introduced by Pati and Salam in 1973.

When we look at this new unified pattern,

we can see a couple of gaps where particles seem to be missing.

This is the way theories of unification work.

A physicist looks for larger, more symmetric patterns

that include the established pattern as a subset.

The larger pattern allows us to predict the existence of particles

that have never been seen.

This unification model predicts the existence

of these two new force particles,

which should act a lot like the weak force, only weaker.

Now, we can rotate this set of charges in seven dimensions

and consider an odd fact about the matter particles:

the second and third generations of matter

have exactly the same charges in six-dimensional charge space

as the first generation.

These particles are not uniquely identified by their six charges.

They sit on top of one another in the standard charge space.

However, if we work in eight-dimensional charge space,

then we can assign unique new charges to each particle.

Then we can spin these in eight dimensions

and see what the whole pattern looks like.

Here we can see the second and third generations of matter now,

related to the first generation by a symmetry called "triality."

This particular pattern of charges in eight dimensions

is actually part of the most beautiful geometric structure in mathematics.

It's a pattern of the largest exceptional Lie group, E8.

This Lie group is a smooth, curved shape with 248 dimensions.

Each point in this pattern corresponds to a symmetry

of this very complex and beautiful shape.

One small part of this E8 shape can be used to describe

the curved space-time of Einstein's general relativity,

explaining gravity.

Together with quantum mechanics,

the geometry of this shape could describe everything

about how the universe works at the tiniest scales.

The pattern of this shape living in eight-dimensional charge space

is exquisitely beautiful,

and it summarizes thousands of possible interactions

between these elementary particles,

each of which is just a facet of this complicated shape.

As we spin it, we can see many of the other intricate patterns

contained in this one.

And with a particular rotation,

we can look down through this pattern in eight dimensions along a symmetry axis

and see all the particles at once.

It's a very beautiful object,

and as with any unification,

we can see some holes where new particles are required by this pattern.

There are 20 gaps where new particles should be,

two of which have been filled by the Pati-Salam particles.

From their location in this pattern, we know that these new particles

should be scalar fields like the Higgs particle,

but have color charge and interact with the strong force.

Filling in these new particles completes this pattern,

giving us the full E8.

This E8 pattern has very deep mathematical roots.

It's considered by many to be the most beautiful structure in mathematics.

It's a fantastic prospect that this object of great mathematical beauty

could describe the truth of particle interactions

at the smallest scales imaginable.

And this idea that nature is described by mathematics is not at all new.

In 1623, Galileo wrote this:

"Nature's grand book, which stands continually open to our gaze,

is written in the language of mathematics.

Its characters are triangles, circles and other geometrical figures,

without which it is humanly impossible to understand a single word of it;

without these, one is wandering around in a dark labyrinth."

I believe this to be true,

and I've tried to follow Galileo's guidance

in describing the mathematics of particle physics

using only triangles, circles and other geometrical figures.

Of course, when other physicists and I actually work on this stuff,

the mathematics can resemble a dark labyrinth.

But it's reassuring that at the heart of this mathematics

is pure, beautiful geometry.

Joined with quantum mechanics,

this mathematics describes our universe as a growing E8 coral,

with particles interacting at every location in all possible ways

according to a beautiful pattern.

And as more of the pattern comes into view using new machines

like the Large Hadron Collider,

we may be able to see whether nature uses this E8 pattern or a different one.

This process of discovery is a wonderful adventure to be involved in.

If the LHC finds particles that fit this E8 pattern,

that will be very, very cool.

If the LHC finds new particles, but they don't fit this pattern --

well, that will be very interesting, but bad for this E8 theory.

And, of course, bad for me personally.

(Laughter)

Now, how bad would that be?

Well, pretty bad.

(Laughter)

But predicting how nature works is a very risky game.

This theory and others like it are long shots.

One does a lot of hard work knowing that most of these ideas

probably won't end up being true about nature.

That's what doing theoretical physics is like:

there are a lot of wipeouts.

In this regard, new physics theories are a lot like start-up companies.

As with any large investment,

it can be emotionally difficult to abandon a line of research

when it isn't working out.

But in science, if something isn't working,

you have to toss it out and try something else.

Now, the only way to maintain sanity

and achieve happiness in the midst of this uncertainty

is to keep balance and perspective in life.

I've tried the best I can to live a balanced life.

(Laughter)

I try to balance my life equally between physics, love and surfing --

my own three charge directions.

(Laughter)

This way, even if the physics I work on comes to nothing,

I still know I've lived a good life.

And I try to live in beautiful places.

For most of the past ten years I've lived on the island of Maui,

a very beautiful place.

Now, it's one of the greatest mysteries in the universe to my parents

how I managed to survive all that time

without engaging in anything resembling full-time employment.

(Laughter)

I'm going to let you in on that secret.

This was a view from my home office on Maui.

And this is another,

and another.

And you may have noticed that these beautiful views are similar,

but in slightly different places.

That's because this used to be my home and office on Maui.

(Laughter)

I've chosen a very unusual life.

But not worrying about rent

allowed me to spend my time doing what I love.

Living a nomadic existence has been hard at times,

but it's allowed me to live in beautiful places

and keep a balance in my life that I've been happy with.

It allows me to spend a lot of my time hanging out with hyperintelligent coral.

But I also greatly enjoy the company of hyperintelligent people.

So I'm very happy to have been invited here to TED.

Thank you very much.

(Applause)

Chris Anderson: Stay here one second.

(Applause)

I probably understood two percent of that,

but I still absolutely loved it.

So I'm going to sound dumb.

Your theory of everything --

Garrett Lisi: I'm used to coral.

CA: That's right.

The reason it's got a few people at least excited

is because, if you're right, it brings gravity and quantum theory together.

So are you saying that we should think of the universe, at its heart --

that the smallest things that there are,

are somehow an E8 object of possibility?

I mean, is there a scale to it, at the smallest scale, or ...?

GL: Well, right now the pattern I showed you

that corresponds to what we know about elementary particle physics --

that already corresponds to a very beautiful shape.

And that's the one that I said we knew for certain.

And that shape has remarkable similarities --

and the way it fits into this E8 pattern, which could be the rest of the picture.

And these patterns of points that I've shown for you

actually represent symmetries of this high-dimensional object

that would be warping and moving and dancing

over the space-time that we experience.

And that would be what explains all these elementary particles that we see.

CA: But a string theorist, as I understand it,

explains electrons in terms of much smaller strings vibrating --

I know, you don't like string theory -- vibrating inside it.

How should we think of an electron in relation to E8?

GL: Well, it would be one of the symmetries of this E8 shape.

So what's happening is, as the shape is moving over space-time, it's twisting.

And the direction it's twisting as it moves is what particle we see.

So it would be --

CA: The size of the E8 shape, how does that relate to the electron?

I feel like I need that for my picture. Is it bigger? Is it smaller?

GL: As far as we know, electrons are point particles,

so this would be going down to the smallest possible scales.

So the way these things are explained in quantum field theory is,

all possibilities are expanding and developing at once.

And this is why I use the analogy to coral.

And --

in this way, the way that E8 comes in

is it will be as a shape that's attached at each point in the space-time.

And, as I said, the way the shape twists --

the directional along which way the shape is twisting

as it moves over this curved surface --

is what the elementary particles are, themselves.

So through quantum field theory,

they manifest themselves as points and interact that way.

I don't know if I'll be able to make this any clearer.

(Laughter)

CA: It doesn't really matter.

It's evoking a kind of sense of wonder,

and I certainly want to understand more of this.

But thank you so much for coming. That was absolutely fascinating.

(Applause)