March 14, 2019 • 34 mins
Quantum Field Theory, explained!
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Episode Transcript
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Speaker 1 (00:06):
Hey, Daniel, you know how in science fictions are all
kinds of fields. You mean like big expansive lawns. No,
I mean like force fields or energy fields. Oh my god,
you know none of that is real, right? What the
force from Star Wars is not real? None of it. Absolutely,
none of that is real. Wait? Wait, what about like
(00:27):
energy fields? Those are real? Right? Energy fields are not real.
But there's something that's even weird or even cooler that
is real. Wait, cooler than star wars. Cooler than star
Wars are quantum fields. And that's a thing that is
real and is everywhere in the universe. I don't believe it.
I think you just made it up. We physicists did,
(00:48):
in fact, invent quantum fields. But it turns out because
it accurately predicts what happens in the universe, it might
just be real. Is that like field of dream Like
if you think of it, people will believe it. That's right,
quantum fields of quantum dreams. That's basically what being a
physicist is all about, having quantum dreams. And you're the
Kevin Costner in the situation him and I'm Daniel, and
(01:27):
welcome to our podcast. Daniel and Jorge explain the universe.
This is Daniel and Jorge. This is the podcast you're
looking for exactly um. Yeah. On this podcast, we try
to talk to you about everything in the universe. Things
that are big, things that are small, things that are
invisible but fill the entire universe, things that are everywhere,
(01:48):
things you had no idea existed, but determine everything about
your existence that's right. Today on the podcast, we'll talk
about quantum fields. What are they? Where are they? Who
are they? What are they good for? Absolutely nothing? Say
it again. Is it's just a family whose last name
(02:10):
is field, or it's a bunch of discrete playing fields
somewhere quantum fields, you're gonna have one field, you can
have two fields. You can't have two and a half fields.
They're quantized, but once you enter, you don't really know
where you're going or where you are now. A quantum
field theory is something you hear about, you might have heard.
(02:30):
It's part of modern physics. It's a theory that people
use to do calculations. It's really awesome, it's impressive. But
what isn't What is a quantum field? What is the
theory of quantum fields? What relationship does that have to
you or the rest of your life or anything at all. Well,
it's more than just a part of modern physics. It's
kind of like the foundation of our theory about the universe. Right,
(02:52):
that's right. It's kind of like the language of physics currently.
You know, it's quantum field theory is to modern physics
the way like English is to Shakespeare. You know. We
use the tools of quantum field theory to try to
talk about what's going on in the universe, and it's
remarkably successful. It's incredibly successful. When you guys want to
use pig latin, I thought that was the We only
do that when you come by, Jorge to try to
(03:13):
confuse you. Um. But it's like the foundation of modern physics.
And it's also super duper accurate. Like you guys are
pretty sure is it the right way to describe the universe? Yeah, Well,
on one hand, it's super duper accurate. Like we can
predict the way particles interact with fields, and we can
make predictions out to lots of decimal places, and then
(03:36):
we can go out and measure how those particles interact
with the fields, and it turns out those predictions are
correct to like one in millions and millions. So you know,
you have, on one hand, like a theoretical calculation that
you've written downs is like an idea that predicts an experiment,
and then you go out and you check it with
a super precise experiment and get the same answer, and uh,
you know it's so accurate that you think maybe this
(03:58):
is the true story of the universe. It's not just
like human ideas. This is like revealing the source code
kind of thing. So you're pretty close to saying quantum
fields are true. They're they're like the truth of the universe. Yes,
that's except that we also know they can't be the
final answer. Oh yeah, well well we'll get into it.
(04:20):
But I will admit I don't have a clear idea
of what a quantum field is um and we were
wondering how many of you out there had some ideas
about what it would be. So, as usual, I walked
around the u C Irvine campus and I asked a
bunch of very friendly, very accommentating, very willing to answer
random questions you see, Irvine undergrads, and I asked them
what is quantum field theory? Here's what people had to say.
(04:43):
I have no idea, but I have heard of before.
All right, Um, it's probably really to quantum mechanics UM.
I'm not sure exactly what it is, but I think
it describes the different factor of fields that you use
in quantum mechanics. UM. Maybe the way cell atomic particles
(05:07):
instracted with one another cool um, similar to quantum mechanics chemistry.
I don't know what it is, but I've heard of it.
It's something to do with general relativity. Is it trying
to marry that together with quantum theory? Are the waves
involved and residents of particles? Something like that? Maybe? All right,
(05:29):
some pretty pretty good answers. I feel like, though the
word quantum just give it away, you know, asked what
is the quantum Google book, you can just say, oh,
I think it's related to quantum particles, right, and you
would be sort of right, yeah, but that's not really
an answer, right, you know. Um? And and we know
one of those answers is actually not from a UC
(05:49):
Irvine undergraduate. That's from a fellow who wrote in and
said that he was disappointed with the quality of the
answers that the undergrads were giving. He thought he could
do better. So I said, all right, here's the next
question from the next podcast. Don't do any research and
record your answer. And he wrote back a very humbled
email and he said, Okay, you're right. It's harder than
(06:11):
I thought it was, but he was still willing to
do it, so I thought that was totally awesome. So
he sent us. He sent us his description of quantum
field theory. Do you think that we think in society
today we think for smarter than we are because we
have Google at our fingertips. You know, I feel like
you know everything because we kind of do. If we
just give us a second to tap it on our phones,
it's easier to access information. But sometimes that makes me
(06:33):
feel less smart because I feel like I have less
information actually in my head and I'm relying more and
more on these facilities that are outside my brain. You
know this, Even though the cognitive connection between me and
Google keeps increasing, I don't feel like that makes me smarter.
It just makes me plus Google smarter. What what about
the day that you get you connect your phone through
(06:54):
your brain or something, then you're sort of technically as
smart as Google. The day that I become Google. That's
the singularity, the Google's singularity. Yeah, we all connect our brains,
we all become one mega consciousness. The Google were smoking
over there today, Jorge, I want some pass that over.
It's the googlarity, the Google larity. I look forward to that.
(07:16):
But well, we know they're related to quantum theory, quantum
field um. So let's let's let's break it down. First
of all, what is a field to a physicist? Right? So,
a field is just it's like a fluid that feels
all of space. It's like it's something that's everywhere and
everywhere in space. You have a number, right, And it
comes from things like the electromagnetic field. People were puzzling
(07:40):
a hundred years or so ago, like how do to
magnets push each other apart without touching? Right? There was
this action at a distance mystery like that's sort of spooky,
like a yeah, right are they? How are they actually
pushing each other apart? You know? And this really puzzled
physicists for a while, and they came up with this
idea of a field, the idea that each magnet has
a magnetic field. It's this invisible thing that surrounds it,
(08:03):
which will push on any other magnet that enters that
magnetic field. Right, and the magnetic field is strongest near
the source of the magnet and then it drops off
just as you would expect because the magnet super far
away won't feel anything. And just came because they noticed
that how one magnet pulls or pushes on another sort
of depends on where you put them relative to each other, right,
(08:25):
Like where you put it around the other other one,
that's right. And so they came up they said, well, wait,
maybe every magnet generates in space this invisible thing. We'll
call it a magnetic field, and that's the thing that
does the pushing. And sort of a mystery that came
up immediately was like is the field a real thing?
Is it actually they're a physical thing that's that exists
(08:46):
in the universe, Like does it have substance and can
you play baseball on it? Or is it just a
way that we calculate things, you know, just like a
tool in our minds to help us understand things, Like
is it a thing like you said, it could be
like a fluid, or it could just be like a
mathematical construct exactly exactly. And that's the questions people are
(09:06):
still grappling with, right. One philosophical problem was how can
things that are not touching push and pull on each other?
And they answer that with okay, we just invent fields
all right? Now the question is our fields a real
thing or are they something else? You know, that's the
joy of philosophies that every time you answer a question,
it just creates another question which is just as deep.
But what do you mean by a field is like
(09:28):
a number? Because the way I learned about it in
engineering is that a field is basically something that gives
you a number depending on where you stand or where
you are in space. That's right, Every point in space
has a number associated with it with each field. So
for example, the magnetic field from a magnet, there's a
strength of that field. There's a field strength and every location.
(09:49):
So as you're saying, you can ask what is the
field strength here right next to the magnet and you
get a number. What is the field strength way over there,
far away from the magnet, and you get a smaller number.
So the magnetic fiel field has a number at every
point in space. And you can have different kinds of
fields you can feel that just have a number. Those
are called scale or fields. That's just a fancy way
of saying a number, or you can have vector fields.
(10:10):
You can have a field where at every point you
have an arrow that points in a certain direction. It's
like kind of like, are you saying it's a field
that's kind of like a map, like it tells you
what is it every position in space? Yeah? Or a
map is kind of like a field actually, um, yeah, exactly.
So you can think of for like a map is
how much magnetic field is there here? How much magnetic
(10:31):
field is there there? And you know everywhere in space
there is magnetic field and easither you're strong or it's weak. Right,
it can be if you're talking about like ordinary classical
fields like from a hundred and fifty years ago, then
they can be zero. Right, No magnets means there's a
field there, but the field value is zero. So the
question is is a field just like a map that
(10:51):
we hold in our hands it tells these things? Or
are we actually living on a map? Right? Like is
a field a real thing of substance? Yeah? And the
answer that question is we have no idea. And it's
sort of a philosophical question more than a scientific one. Right.
If you have a calculational tool a field that lets
you predict the outcome of experiments and that works really
(11:12):
really well. Doesn't matter if it's really physically true the
thing that's happening, um or just or just a the
way do you do these calculations? What's the difference? Right? Um?
You know, if we weren't here with those fields exist, right, well,
that's not really a question you can answer because if
we weren't here, there'd be nobody to answer the question
or do the experiment, right. So they're really tricky little
(11:35):
philosophical puzzles. And that's a whole area of philosophical exploration
that I'm totally not qualified to talk about, but I
often do anyway that do. That's the basis of our
entire podcast. That's the field of our podcast. Now, you know,
there's a huge conflict between philosophers of science and physicists
who think there's philosophers of science and spout off glibly
(11:59):
sometimes um an uninformed way in front of mass audiences
and then get taken down by actual philosophers of science.
So that's a common mistake to make, which is why
I wanted to put that qualifier out there. In the
world economic war kind of between the pilosophers and physicists
who venture into philosophy. Yes, exactly, exactly right. And there
(12:23):
are some physicists who really have learned about philosophy and
can speak knowledgeably about it. And then there are others
who think they can speak knowledge of me about it
but don't actually know anything. It sounds like an exciting fight,
ironically speaking. All right, so, um, so that's a field.
That's kind of what it is. It's kind of like
a map of space that tells you something. Um, And
(12:46):
then you can have particles in these fields, right, Like
a particle is part of the field, or something can
be on the field. Yes. One of the most interesting
thing about field theories or theories of fields is it
tells you that particles are not the most basic thing
in the universe. The particles are, in fact, just vibrations
of the field. Like particles are a real thing. Right,
(13:06):
We feel them, we see them, we are them. But
this tells us what they where they come from? Right
the rules. It tells us that if you want to
understand how particles move, you really have to understand these fields,
because the particles are just vibrations in those fields, but
vibrations of what of the fields? Right, Like the fields
are you know, a thing and they vibrate, which means
(13:28):
they have energy, right, and localized excitations of these fields. Right.
Imagine for example, a big rubber sheet that fills the
universe right, totally flat, but you could um poke it
and send a wave through it, right, and that wave
can travel. It's energy that's traveling by oscillating this field.
And that's what particles are. There are oscillations in fields.
(13:50):
But if I poke a sheet, it'll sort of dissipate,
It'll go outwards and dissipate. A particle kind of likes
to stay in one place. Well, I don't know what
particles like. You've done any interviews with particles, and you
can um, there's lots of waste of vibrated sheet, right,
you can vibrted sheet, so you get a localized packet
that's traveling. Right. It's easier to think about, for example,
(14:12):
in one dimension, like instead of a sheet, think of
a rope. Like if I'm holding a rope and you're
holding a rope, I can wiggle it to send you
like a little wiggle along the rope, so you can
get a message. Right, And you're saying a particle is
one of these wiggles. A particle is a localized excitation
of the quantum field exactly. And the crazy thing is
every particle has its own field. So like in the universe,
(14:35):
everywhere there's an electron field, and everywhere there's an electron
that's the electron field wiggling, wiggling, And there's also a
um cork field, right, an upcork field. Everywhere there's an
upcork The upcork field is wiggling. Like a particle is
something that's causing the field to vibrate or it's like
it is the vibration of the field. It is the
vibration exactly, That's what it is. Yeah, And so that's
(14:59):
what we're all made out of. Like you and I
are made out of protons and quirks and electrons, and
so we're all just like massive collections of little vibrations.
That's right. It's all actually vibrations. Man, those dudes, that's
not a vibrations were everything they were right in exactly.
And so for if you like to think of yourself
as made of particles, and you wonder like, well, what
(15:21):
are the particles made out of? Right, I mean, they
might be made out of smaller and smaller particles. But
at some point you get down to the smallest particle
and what's that particle made out of? And you think, oh,
universe stuff. Well, it turns out the universe stuff might
be quantum fields, right, that it's the quantum fields that
are oscillating that make a particle. Okay, So that's a
definition of a quantum field. It's it's the stuff of
the universe. We're done. Yeah, So a field is just
(15:44):
like a fluid field space. It could doesn't have to
become quantum. It could be like electromagnetic or in any
kind of field. But a quantum field is a field
that describes the motion of a quantum object, like a particle.
And so since we're dealing with particles and they move
really fast and they have quantum entical properties, we deal
with quantum fields. Okay, So a quantum field is what
(16:06):
describes the things that we're made out of, right, because
we're all made out of quantum particles, that's right, And
every particle that makes us up is actually just a
vibration of one of those fields, you know. And it's
a really different way to look at the universe. Like
when physicists started and they were thinking about quantum mechanics.
They were thinking about, like what happens to a particle?
You know what, what is this electron story? It starts
(16:28):
off over here and then it goes off over there.
And that's the way we're used to do in physics, right,
Like you think about a ball, what happens to this
ball as it rolls down the hill. It's very natural
to sort of follow the story of the ball. So
we tried to do that with us, follow the story.
The electron problem is quantum particles don't behave like that,
Like they don't have a path, right, It's not like
you're here and then you're here and then you're here.
(16:50):
Is all this uncertainty, But more than that, they're being
destroyed and created all the time. Like an electron doesn't
just fly through space. It flies through space, it turns
into aton and something else, then it turns back into
an electron, and then it creates this other thing which
exists for a bill of second and then comes back.
This is like frothing mass of stuff that's happening. And
the quantum mechanics we first developed couldn't describe that at
(17:12):
all because it was very difficult to describe the creation
or destruction of particles. So you sort of like reboot
your thinking completely and say, let's ignore the story of
one particle and just think about like the particles in general. Right,
let's think about all the particles. It's just like vibrations
of this sheet that fills the universe. And then we
don't have to worry about the story of particle A
and the story of particle B. Because, um, you're saying
(17:36):
an electron. If you think of it as a thing,
and that thing disappears and turns into something else, then
you're left wondering what happened to that thing? Yeah, Like
Kevin the electron, what is his story? He disappeared and
he came back. Is it's still Kevin? Right, Like in
the quantum field theory version, Like all the electrons are
Kevin because all the electrons are the same, right, Every
electron is identical. Right, there's no difference between this electron
(17:58):
and that electron. Where all Kevin, we're all made out
of Kevin. Turns out that's the answer to the life,
the universe and everything. Kevin. There's like twelve Kevin's listening
to this, going, I knew it. I hope we have
more than twelve Kevin's listening to this. Well, let's get
a little bit deeper into it. But first let's take
a quick break. Okay, so you're saying that the universe
(18:32):
is not empty. It's like it's filled with these quantum
fields that just kind of permeate everything. And they might
be imaginary or they might be real things, but they
premiate the entire universe. And we, like particles us matter,
are just kind of like um little vibrations in these fields,
that's right. And they lay on top of each other, right,
(18:53):
Every point in space can have an electron field and
an upcork field, and a down cork field, and a
Higgs boson on field and electromagnetic field. We have lots
of different kinds of fields, and you know, it might
turn out eventually that we figure out how they're all
really just part of one big field. But right now,
we have lots of different kinds of fields that all
sort of lay on top of each other. They're all
the same size, or all the size of the universe.
(19:15):
Every piece of space has all these fields, and some
of them are zero ish, you know, they're low, and
some of them have energy in them, which is why
you have the electron here. So if you have like
an electron on your left, that means the electron field
is excited there. And if you have an upcork on
your right, it means the upcork field is excited there
and the electron field is not. Right. But and they
can sort of talk to each other, right, Like an electron,
(19:37):
you could have a little vibration in the electron field
and then suddenly that disappears and it gets transferred to
a different field and becomes a different particle exactly. And
those are the forces. So quantum field theory can describe matter.
That's what we've been talking about. They could also describe
the forces like the electromagnetic field is a way for
charge particle fields to interact with each other. Right, you
(19:57):
have one electron over here, another electron over there. How
do they talk to each other? Well, turns out the
electron field and the photon field interact, and so one
electron can talk to another electron by shooting a ripple
through the photon field, which is like sending a photon
between one electron and the other through another field. Yes, exactly,
the fields coupled to each other, they interact otherwise would
(20:19):
be pretty boring universe, and in these fields fill the
entire universe. So are they related to space, like if
if space grows, these fields grow as well. Yes, exactly,
it's a basic part of space, right, you can't have
space without these fields. As far as we know. There's
no fieldless part of space, and every part of space
has these fields. It's like there's a hum at every
(20:40):
point in the universe. There's no quiet place in the
universe exactly. And you might be thinking, well, what if
you have an empty space, maybe all the fields are
just zero. Right, Well, that's the fascinating thing about quantum fields,
right because uncertainty principle, because there's a maximum amount of
information you can have. You can't have quantum field to
be exactly at zero. There's a minimum amount of inner
g they have to have, so they can bubble and
(21:02):
slosh in a way that gives you that uncertainty. Wait wait, wait, um,
there's there's kind of like an inherent energy in these
quantum fields. That's right, Like they're positive. I guess they're
they're not zero exactly. You can't have quantum fields exactly
at zero, and so there's always some energy there and
this is the energy of empty space, right, and that
(21:23):
energy means you have energy and you can create an
electron and depositron which then annihilate themselves back into a
photon or back into something else. So this energy is
always bubbling and frothing. And I feel like this kind
of makes it kind of makes anything possible. Right like before,
when you when you were is there something specific you
want to do? Accomplish with the punting field, you wanted
(21:44):
to do your dishes, get away with something I wanted
to get away with, or or imagine that I can
do you No, What I mean is in the sense
that before, if you were keeping track of all particles,
like if I was made out of the Kevin particles,
then there's sort of no way for me to suddenly
disappear and a you're over there. But now, because everything
is a quantum field, I could choose magically for some reason. Rights,
(22:08):
It's not like because we have quantum fields, there are
no rules, right, There are specific rules for how quantum
fields interact with each other and and how things propagate
through quantum fields, and you know, so we still have
laws of physics. It's not like we're tossing the laws
out the window and you do whatever you like. The
parents are out of town, right um, there's it's just
another way of looking at the universe. Okay, all right,
(22:29):
I guess what I mean is, you know stuff can
appear out of nowhere with these quantum fields. Yes, okay,
it's certainly true that a lot of your intuition is wrong,
and the quantum fields tell us that crazy things could happen,
And then we do the experiments and it's right, right,
quantum quantum field theory seems to be correct. It's a
(22:49):
pretty interesting view of the universe. You know, we think
of it as big and empty, but really there's sort
of like a like a little froth in the background
where a little like simmering bubbling. Yeah, exactly, there's no
place that's actually empty. Either's energy everywhere, and it's it's
filled with possibilities literally, and it's a it's a fascinating
way to look at the universe, and it's led to
a lot of insights. I mean, just like this mathematical
(23:11):
way of thinking about things has revealed things about the
universe we didn't know. For example, like what like the
Higgs boson. The Higgs boson was just an idea. Right
fifty years ago, Peter Higgs and several others said, huh,
what if there was another field? We'll call it the
Higgs field conveniently, And you know, where did you get
this idea? Where did this idea come from? Right? Who
(23:33):
wouldn't want to postulate a field that fills the universe?
And it is named after themselves? Right? Do you think
he named it after himself or people named it after him? Oh,
there's a whole controversy there about who named the Higgs fields,
And it comes down to um who submitted a paper first,
and whether a paper is dated based on the submission
date or the acceptance dage. You know, I mean like,
(23:56):
did Higgs write in his paper I'm going to call
this the Higgs field or did you say it's the
age or b? And then that somebody said, oh, that's
the field Higgs was talking about. Yes, somebody later referred
to it as the Higgs field because Higgs paper has
the earliest date on it. But he actually submitted his
paper after some other folks. Their paper had a later
date on it because the paper had the acceptance date
(24:18):
on it, not the submission date. So somebody later gave
Higgs credit, maybe inappropriately. Okay, so you're saying that these
fields are not just kind of need to think about,
but they've actually led to real discoveries and real understanding
of the universe. Yeah. It was a guy named Steve
Weinberg who read Higgs paper. He was looking at these
fields and he was thinking, thinking, there's a mystery here,
(24:40):
there's a pattern here that doesn't quite work, and that
comes from trying to unify the fields. We've talked on
other podcasts about how the electromagnetic field and the weak
nuclear field, Right, those two forces are actually parts of
the same thing, and they're very similar. But the difference
is that the photon, the thing that moves the electromagnetic field,
has no mass, right, It's it's massless. And the thing
(25:03):
that moves the weak nuclear force are the w n
z bosons. They're really heavy. So Weinberg was like, if
these are two parts of the same thing, how come
one has no mass and the other one has a
huge amount of mass? Right? What could do that mathematically?
Like theoretically, how could you make that happen? And the
what he found was the simplest way to do that,
(25:24):
the easiest, the clearest, like the without adding the minimal
number of moving pieces was to add one more field.
And so he read that paper by Higgs and he thought, Aha,
that is just the field we need. So he said,
if you add this field, and it explains this mystery
why photons have no mass and why the w z
have a lot of mass, But it, you know, creates
(25:45):
another field that feels the universe. So let's go see
if that's real. And but what's interesting is that there
were other people positing other fields, right, Like, he wasn't
the only one. He wasn't the only one. Other people
had similar ideas, and then there are other totally competing ideas,
you know, for ways to solve that mystery with other
different fields. Yeah, exactly. So like I could say, hey,
there's a horhe field that permius everything. Yeah, you could,
(26:08):
and I would be a physicist. Boom, you're a physicist
right here today on the podcast and deputize you. Yeah. Alright,
So if you wanted to propose a field, they would
have to solve a problem, right, like why this field
and not some other fields? And you'd have to provide
a way for us to check, like what in what
experiment could we see the Jorge particle, right, which is
(26:30):
an excitation of the Jorge field, right, and the same
as the Higgs boson is an excited state of the
Higgs field. Right. You have to provide some way for
us to do that, and Peter Higgs did. He's like, oh, well,
if you smash protons together this energy, you should see
a certain number of Higgs particles. All right, So, um,
i'll table that for my next career after we have
a podcast host in a world where cartoonists try to
(26:54):
be physicists. Before we keep going, let's take a short break. Um, okay.
So yeah, it's it's like it's like, really the basic
(27:14):
theory of everything, you know, matter, light, forces, energy, any
kind of everything out there, we describe it using quantum fields.
Almost everything is there? Yeah? Is there something we don't
describe with quantum fields? Yeah, And it's always the same thing.
It's the black sheep of physics. It's gravity. It's quantum
(27:35):
field theory describes matter, it describes electromagnetism, it describes the
weak nuclear force, it describes the strong nuclear force. It
even can incorporate special relativity, meaning we understand what happens
when electrons go super duper fast close to the speed
of light. Right, But quantum field theory is easiest when
space is flat. I mean, we can do quantum field
(27:57):
theory and curved spaces, but it gets really nasty in space.
Getting curved is exactly what general relativity says will happen.
So what quantum field you're saying, don't work in space
that is not flat, like, it only works in flat space.
Not exactly. We can do it, but it's not easy.
It's not a lot of fun. Why not? Why not? Um,
(28:21):
it's a no, it's a great question. It's a great question.
So the issue is more about figuring out how to
get quantum field theory, to explain that curvature, to generate
that curvature, to get a quantum field theory description of
how space gets curved. Like, I like your space curves
or contracts. What does that do to the quantum field?
Doesn't it just squishes it or bends it? Oh? Yeah,
(28:42):
you're right, it just squishes it. Thanks. We just solve
that problem, all right, Um, check that off the list
of modern physics mysteries. Nobel Prize please, Yeah, the squish function.
We'll decide this function. Um. I think also the larger
problem is that we don't know how to describe gravity
in terms of a quantum field. Right, electromagna autism and
all these other forces we can describe as oscillations in
(29:03):
the field. Right, and that fields associated with its own particle.
The photon is is the particles is associated with the
field for electromagnetism, the gluon is the particle associated with
the field. For the strong nuclear force. We have never
been able to describe gravity in terms of a quantum field,
like a gravitational field field space and has a particle
associated with the graviton. We try to do that. We
(29:27):
try to do those theories and write them down, but
you get crazy answers, you get infinities where you should
get reasonable numbers, and just doesn't work on and so
even if you came up with the gravity quantum field
and the graviton, it's still you're saying by itself, it's
not consistent even in flat space. That's right, it's um.
We can't make those theories work. I mean, people have tried,
and people are trying, and they're writing down theories of
(29:49):
quantum um gravity, but those theories don't make testable predictions
that make sense. You know, They predict infinities. You know,
what is the force between these two particles? Infinity? How
much mass does this thing have? Infinite? So it makes
predictions which your nonsense, and we haven't been able to
fix them mathematically. What if it does have infinite masks?
No wonder, I feel so sluggish today, I have infinite masks.
(30:12):
Um alright, So quantum fields they PerMIATE everything. They describe
everything that we know about almost except gravity, except gravity,
and and and they're amazingly accurate, like you're you're telling
me earlier. They can predict things up to like ten
(30:33):
decimal places. Yes, exactly, it's super accurate. Like if you
exclude gravity, we can do these experiments and we can
check them and we get bang on the right answer
to as far as we can measure. You know, it's
a kind of thing that makes me wonder if we
really have pulled back the curtain of nature and seeing
the way the world really works. You know, yeah, yeah,
that sort of makes me all wonder. You know, if
(30:54):
this is the way the universe works? What makes these fields? Like,
what's what's their origin? Where do they come from? You
just never satisfied, are you, Jorge? We explain matter in
terms of particles. We explained particles in terms of fields,
But you're like, I want more. What makes up the fields? Yeah?
How far? How far does the rabbit hole go? Yeah?
I mean we've explained the way matter works in terms
(31:16):
of particles, and particles work in terms of fields and so,
and then of course the next natural question is you
know what makes the fields? Are the fields actually just
something else? Right? Uh, the wiggling of strings or you know,
the dancing of tiny puppies or something. We don't know,
and we don't know. If we get that answer, if
there's not another question behind it, right, it goes even deeper.
(31:37):
Is there an end of this rabbit hole? We have
no idea. Frankly, I hope not. I think the answer
is clear. It's made to Glorian's obviously making absolutely. Yeah,
that was definitely a documentary. So you know, the next
time you are out walking around in the world and
you look up at the sky and you are amazed
at how beautiful things are, remember that deep down underneath
(31:59):
it's a hot, sasty, frothing mess of quantum fields, oscillating
and interacting and bouncing against each other and doing crazy
calculations just to make your everyday world work for you. Yeah,
I like to think of it more as happy fields,
maybe not so like nasty What if they're happy fields? Happy?
What's happy about these fields? They're like zinging and zinging
and interacting with each other, and they're like never resting,
(32:21):
you know, they're they're not like slow lingorious lazy fields.
You know, these are hyper fields. But it's interesting. I
think it sort of makes me think that maybe in
a way, we are all connected, you know, if we're
all just vibrations in these mysterious quantum fields of stuff,
(32:42):
we're all sort of part of all We're all connected,
you know, we're all part of part of the same
stuff that the universe is made out of. That's right, Me,
you and Kevin, who are all really the same, all
the Kens, all of them, all the Kevin's, We are
all the Kevin's. Basically, that's my new religion, the Church
of Kevin to the Church of the Flying Kevin Monster.
(33:02):
Now we are all oscillations in the same universe expanding fields.
That is true. All right, Well, I hope you enjoyed
that quantum field discussion. Thanks for tuning in, And if
you have some crazy concept in physics you'd like us
to break down, send it to us at Feedback at
Daniel and Jorge dot com. Or if your name is Kevin,
we have reserved an email address for you, which is
(33:24):
Kevin at Daniel and Jorge dot com. That's right, and
if you have secrets to the universe, Kevin, please send
them to us at that address. See you next time.
Thanks for listening. If you still have a question after
(33:45):
listening to all these explanations, please drop us a line.
We'd love to hear from you. You can find us
at Facebook, Twitter, and Instagram at Daniel and Jorge that's
one word, or email us at Feedback at Daniel and
Jorge dot com. One
Hey, Daniel, you know how in science fictions are all
kinds of fields. You mean like big expansive lawns. No,
I mean like force fields or energy fields. Oh my god,
you know none of that is real, right? What the
force from Star Wars is not real? None of it. Absolutely,
none of that is real. Wait? Wait, what about like
(00:27):
energy fields? Those are real? Right? Energy fields are not real.
But there's something that's even weird or even cooler that
is real. Wait, cooler than star wars. Cooler than star
Wars are quantum fields. And that's a thing that is
real and is everywhere in the universe. I don't believe it.
I think you just made it up. We physicists did,
(00:48):
in fact, invent quantum fields. But it turns out because
it accurately predicts what happens in the universe, it might
just be real. Is that like field of dream Like
if you think of it, people will believe it. That's right,
quantum fields of quantum dreams. That's basically what being a
physicist is all about, having quantum dreams. And you're the
Kevin Costner in the situation him and I'm Daniel, and
(01:27):
welcome to our podcast. Daniel and Jorge explain the universe.
This is Daniel and Jorge. This is the podcast you're
looking for exactly um. Yeah. On this podcast, we try
to talk to you about everything in the universe. Things
that are big, things that are small, things that are
invisible but fill the entire universe, things that are everywhere,
(01:48):
things you had no idea existed, but determine everything about
your existence that's right. Today on the podcast, we'll talk
about quantum fields. What are they? Where are they? Who
are they? What are they good for? Absolutely nothing? Say
it again. Is it's just a family whose last name
(02:10):
is field, or it's a bunch of discrete playing fields
somewhere quantum fields, you're gonna have one field, you can
have two fields. You can't have two and a half fields.
They're quantized, but once you enter, you don't really know
where you're going or where you are now. A quantum
field theory is something you hear about, you might have heard.
(02:30):
It's part of modern physics. It's a theory that people
use to do calculations. It's really awesome, it's impressive. But
what isn't What is a quantum field? What is the
theory of quantum fields? What relationship does that have to
you or the rest of your life or anything at all. Well,
it's more than just a part of modern physics. It's
kind of like the foundation of our theory about the universe. Right,
(02:52):
that's right. It's kind of like the language of physics currently.
You know, it's quantum field theory is to modern physics
the way like English is to Shakespeare. You know. We
use the tools of quantum field theory to try to
talk about what's going on in the universe, and it's
remarkably successful. It's incredibly successful. When you guys want to
use pig latin, I thought that was the We only
do that when you come by, Jorge to try to
(03:13):
confuse you. Um. But it's like the foundation of modern physics.
And it's also super duper accurate. Like you guys are
pretty sure is it the right way to describe the universe? Yeah, Well,
on one hand, it's super duper accurate. Like we can
predict the way particles interact with fields, and we can
make predictions out to lots of decimal places, and then
(03:36):
we can go out and measure how those particles interact
with the fields, and it turns out those predictions are
correct to like one in millions and millions. So you know,
you have, on one hand, like a theoretical calculation that
you've written downs is like an idea that predicts an experiment,
and then you go out and you check it with
a super precise experiment and get the same answer, and uh,
you know it's so accurate that you think maybe this
(03:58):
is the true story of the universe. It's not just
like human ideas. This is like revealing the source code
kind of thing. So you're pretty close to saying quantum
fields are true. They're they're like the truth of the universe. Yes,
that's except that we also know they can't be the
final answer. Oh yeah, well well we'll get into it.
(04:20):
But I will admit I don't have a clear idea
of what a quantum field is um and we were
wondering how many of you out there had some ideas
about what it would be. So, as usual, I walked
around the u C Irvine campus and I asked a
bunch of very friendly, very accommentating, very willing to answer
random questions you see, Irvine undergrads, and I asked them
what is quantum field theory? Here's what people had to say.
(04:43):
I have no idea, but I have heard of before.
All right, Um, it's probably really to quantum mechanics UM.
I'm not sure exactly what it is, but I think
it describes the different factor of fields that you use
in quantum mechanics. UM. Maybe the way cell atomic particles
(05:07):
instracted with one another cool um, similar to quantum mechanics chemistry.
I don't know what it is, but I've heard of it.
It's something to do with general relativity. Is it trying
to marry that together with quantum theory? Are the waves
involved and residents of particles? Something like that? Maybe? All right,
(05:29):
some pretty pretty good answers. I feel like, though the
word quantum just give it away, you know, asked what
is the quantum Google book, you can just say, oh,
I think it's related to quantum particles, right, and you
would be sort of right, yeah, but that's not really
an answer, right, you know. Um? And and we know
one of those answers is actually not from a UC
(05:49):
Irvine undergraduate. That's from a fellow who wrote in and
said that he was disappointed with the quality of the
answers that the undergrads were giving. He thought he could
do better. So I said, all right, here's the next
question from the next podcast. Don't do any research and
record your answer. And he wrote back a very humbled
email and he said, Okay, you're right. It's harder than
(06:11):
I thought it was, but he was still willing to
do it, so I thought that was totally awesome. So
he sent us. He sent us his description of quantum
field theory. Do you think that we think in society
today we think for smarter than we are because we
have Google at our fingertips. You know, I feel like
you know everything because we kind of do. If we
just give us a second to tap it on our phones,
it's easier to access information. But sometimes that makes me
(06:33):
feel less smart because I feel like I have less
information actually in my head and I'm relying more and
more on these facilities that are outside my brain. You
know this, Even though the cognitive connection between me and
Google keeps increasing, I don't feel like that makes me smarter.
It just makes me plus Google smarter. What what about
the day that you get you connect your phone through
(06:54):
your brain or something, then you're sort of technically as
smart as Google. The day that I become Google. That's
the singularity, the Google's singularity. Yeah, we all connect our brains,
we all become one mega consciousness. The Google were smoking
over there today, Jorge, I want some pass that over.
It's the googlarity, the Google larity. I look forward to that.
(07:16):
But well, we know they're related to quantum theory, quantum
field um. So let's let's let's break it down. First
of all, what is a field to a physicist? Right? So,
a field is just it's like a fluid that feels
all of space. It's like it's something that's everywhere and
everywhere in space. You have a number, right, And it
comes from things like the electromagnetic field. People were puzzling
(07:40):
a hundred years or so ago, like how do to
magnets push each other apart without touching? Right? There was
this action at a distance mystery like that's sort of spooky,
like a yeah, right are they? How are they actually
pushing each other apart? You know? And this really puzzled
physicists for a while, and they came up with this
idea of a field, the idea that each magnet has
a magnetic field. It's this invisible thing that surrounds it,
(08:03):
which will push on any other magnet that enters that
magnetic field. Right, and the magnetic field is strongest near
the source of the magnet and then it drops off
just as you would expect because the magnet super far
away won't feel anything. And just came because they noticed
that how one magnet pulls or pushes on another sort
of depends on where you put them relative to each other, right,
(08:25):
Like where you put it around the other other one,
that's right. And so they came up they said, well, wait,
maybe every magnet generates in space this invisible thing. We'll
call it a magnetic field, and that's the thing that
does the pushing. And sort of a mystery that came
up immediately was like is the field a real thing?
Is it actually they're a physical thing that's that exists
(08:46):
in the universe, Like does it have substance and can
you play baseball on it? Or is it just a
way that we calculate things, you know, just like a
tool in our minds to help us understand things, Like
is it a thing like you said, it could be
like a fluid, or it could just be like a
mathematical construct exactly exactly. And that's the questions people are
(09:06):
still grappling with, right. One philosophical problem was how can
things that are not touching push and pull on each other?
And they answer that with okay, we just invent fields
all right? Now the question is our fields a real
thing or are they something else? You know, that's the
joy of philosophies that every time you answer a question,
it just creates another question which is just as deep.
But what do you mean by a field is like
(09:28):
a number? Because the way I learned about it in
engineering is that a field is basically something that gives
you a number depending on where you stand or where
you are in space. That's right, Every point in space
has a number associated with it with each field. So
for example, the magnetic field from a magnet, there's a
strength of that field. There's a field strength and every location.
(09:49):
So as you're saying, you can ask what is the
field strength here right next to the magnet and you
get a number. What is the field strength way over there,
far away from the magnet, and you get a smaller number.
So the magnetic fiel field has a number at every
point in space. And you can have different kinds of
fields you can feel that just have a number. Those
are called scale or fields. That's just a fancy way
of saying a number, or you can have vector fields.
(10:10):
You can have a field where at every point you
have an arrow that points in a certain direction. It's
like kind of like, are you saying it's a field
that's kind of like a map, like it tells you
what is it every position in space? Yeah? Or a
map is kind of like a field actually, um, yeah, exactly.
So you can think of for like a map is
how much magnetic field is there here? How much magnetic
(10:31):
field is there there? And you know everywhere in space
there is magnetic field and easither you're strong or it's weak. Right,
it can be if you're talking about like ordinary classical
fields like from a hundred and fifty years ago, then
they can be zero. Right, No magnets means there's a
field there, but the field value is zero. So the
question is is a field just like a map that
(10:51):
we hold in our hands it tells these things? Or
are we actually living on a map? Right? Like is
a field a real thing of substance? Yeah? And the
answer that question is we have no idea. And it's
sort of a philosophical question more than a scientific one. Right.
If you have a calculational tool a field that lets
you predict the outcome of experiments and that works really
(11:12):
really well. Doesn't matter if it's really physically true the
thing that's happening, um or just or just a the
way do you do these calculations? What's the difference? Right? Um?
You know, if we weren't here with those fields exist, right, well,
that's not really a question you can answer because if
we weren't here, there'd be nobody to answer the question
or do the experiment, right. So they're really tricky little
(11:35):
philosophical puzzles. And that's a whole area of philosophical exploration
that I'm totally not qualified to talk about, but I
often do anyway that do. That's the basis of our
entire podcast. That's the field of our podcast. Now, you know,
there's a huge conflict between philosophers of science and physicists
who think there's philosophers of science and spout off glibly
(11:59):
sometimes um an uninformed way in front of mass audiences
and then get taken down by actual philosophers of science.
So that's a common mistake to make, which is why
I wanted to put that qualifier out there. In the
world economic war kind of between the pilosophers and physicists
who venture into philosophy. Yes, exactly, exactly right. And there
(12:23):
are some physicists who really have learned about philosophy and
can speak knowledgeably about it. And then there are others
who think they can speak knowledge of me about it
but don't actually know anything. It sounds like an exciting fight,
ironically speaking. All right, so, um, so that's a field.
That's kind of what it is. It's kind of like
a map of space that tells you something. Um, And
(12:46):
then you can have particles in these fields, right, Like
a particle is part of the field, or something can
be on the field. Yes. One of the most interesting
thing about field theories or theories of fields is it
tells you that particles are not the most basic thing
in the universe. The particles are, in fact, just vibrations
of the field. Like particles are a real thing. Right,
(13:06):
We feel them, we see them, we are them. But
this tells us what they where they come from? Right
the rules. It tells us that if you want to
understand how particles move, you really have to understand these fields,
because the particles are just vibrations in those fields, but
vibrations of what of the fields? Right, Like the fields
are you know, a thing and they vibrate, which means
(13:28):
they have energy, right, and localized excitations of these fields. Right.
Imagine for example, a big rubber sheet that fills the
universe right, totally flat, but you could um poke it
and send a wave through it, right, and that wave
can travel. It's energy that's traveling by oscillating this field.
And that's what particles are. There are oscillations in fields.
(13:50):
But if I poke a sheet, it'll sort of dissipate,
It'll go outwards and dissipate. A particle kind of likes
to stay in one place. Well, I don't know what
particles like. You've done any interviews with particles, and you
can um, there's lots of waste of vibrated sheet, right,
you can vibrted sheet, so you get a localized packet
that's traveling. Right. It's easier to think about, for example,
(14:12):
in one dimension, like instead of a sheet, think of
a rope. Like if I'm holding a rope and you're
holding a rope, I can wiggle it to send you
like a little wiggle along the rope, so you can
get a message. Right, And you're saying a particle is
one of these wiggles. A particle is a localized excitation
of the quantum field exactly. And the crazy thing is
every particle has its own field. So like in the universe,
(14:35):
everywhere there's an electron field, and everywhere there's an electron
that's the electron field wiggling, wiggling, And there's also a
um cork field, right, an upcork field. Everywhere there's an
upcork The upcork field is wiggling. Like a particle is
something that's causing the field to vibrate or it's like
it is the vibration of the field. It is the
vibration exactly, That's what it is. Yeah, And so that's
(14:59):
what we're all made out of. Like you and I
are made out of protons and quirks and electrons, and
so we're all just like massive collections of little vibrations.
That's right. It's all actually vibrations. Man, those dudes, that's
not a vibrations were everything they were right in exactly.
And so for if you like to think of yourself
as made of particles, and you wonder like, well, what
(15:21):
are the particles made out of? Right, I mean, they
might be made out of smaller and smaller particles. But
at some point you get down to the smallest particle
and what's that particle made out of? And you think, oh,
universe stuff. Well, it turns out the universe stuff might
be quantum fields, right, that it's the quantum fields that
are oscillating that make a particle. Okay, So that's a
definition of a quantum field. It's it's the stuff of
the universe. We're done. Yeah, So a field is just
(15:44):
like a fluid field space. It could doesn't have to
become quantum. It could be like electromagnetic or in any
kind of field. But a quantum field is a field
that describes the motion of a quantum object, like a particle.
And so since we're dealing with particles and they move
really fast and they have quantum entical properties, we deal
with quantum fields. Okay, So a quantum field is what
(16:06):
describes the things that we're made out of, right, because
we're all made out of quantum particles, that's right, And
every particle that makes us up is actually just a
vibration of one of those fields, you know. And it's
a really different way to look at the universe. Like
when physicists started and they were thinking about quantum mechanics.
They were thinking about, like what happens to a particle?
You know what, what is this electron story? It starts
(16:28):
off over here and then it goes off over there.
And that's the way we're used to do in physics, right,
Like you think about a ball, what happens to this
ball as it rolls down the hill. It's very natural
to sort of follow the story of the ball. So
we tried to do that with us, follow the story.
The electron problem is quantum particles don't behave like that,
Like they don't have a path, right, It's not like
you're here and then you're here and then you're here.
(16:50):
Is all this uncertainty, But more than that, they're being
destroyed and created all the time. Like an electron doesn't
just fly through space. It flies through space, it turns
into aton and something else, then it turns back into
an electron, and then it creates this other thing which
exists for a bill of second and then comes back.
This is like frothing mass of stuff that's happening. And
the quantum mechanics we first developed couldn't describe that at
(17:12):
all because it was very difficult to describe the creation
or destruction of particles. So you sort of like reboot
your thinking completely and say, let's ignore the story of
one particle and just think about like the particles in general. Right,
let's think about all the particles. It's just like vibrations
of this sheet that fills the universe. And then we
don't have to worry about the story of particle A
and the story of particle B. Because, um, you're saying
(17:36):
an electron. If you think of it as a thing,
and that thing disappears and turns into something else, then
you're left wondering what happened to that thing? Yeah, Like
Kevin the electron, what is his story? He disappeared and
he came back. Is it's still Kevin? Right, Like in
the quantum field theory version, Like all the electrons are
Kevin because all the electrons are the same, right, Every
electron is identical. Right, there's no difference between this electron
(17:58):
and that electron. Where all Kevin, we're all made out
of Kevin. Turns out that's the answer to the life,
the universe and everything. Kevin. There's like twelve Kevin's listening
to this, going, I knew it. I hope we have
more than twelve Kevin's listening to this. Well, let's get
a little bit deeper into it. But first let's take
a quick break. Okay, so you're saying that the universe
(18:32):
is not empty. It's like it's filled with these quantum
fields that just kind of permeate everything. And they might
be imaginary or they might be real things, but they
premiate the entire universe. And we, like particles us matter,
are just kind of like um little vibrations in these fields,
that's right. And they lay on top of each other, right,
(18:53):
Every point in space can have an electron field and
an upcork field, and a down cork field, and a
Higgs boson on field and electromagnetic field. We have lots
of different kinds of fields, and you know, it might
turn out eventually that we figure out how they're all
really just part of one big field. But right now,
we have lots of different kinds of fields that all
sort of lay on top of each other. They're all
the same size, or all the size of the universe.
(19:15):
Every piece of space has all these fields, and some
of them are zero ish, you know, they're low, and
some of them have energy in them, which is why
you have the electron here. So if you have like
an electron on your left, that means the electron field
is excited there. And if you have an upcork on
your right, it means the upcork field is excited there
and the electron field is not. Right. But and they
can sort of talk to each other, right, Like an electron,
(19:37):
you could have a little vibration in the electron field
and then suddenly that disappears and it gets transferred to
a different field and becomes a different particle exactly. And
those are the forces. So quantum field theory can describe matter.
That's what we've been talking about. They could also describe
the forces like the electromagnetic field is a way for
charge particle fields to interact with each other. Right, you
(19:57):
have one electron over here, another electron over there. How
do they talk to each other? Well, turns out the
electron field and the photon field interact, and so one
electron can talk to another electron by shooting a ripple
through the photon field, which is like sending a photon
between one electron and the other through another field. Yes, exactly,
the fields coupled to each other, they interact otherwise would
(20:19):
be pretty boring universe, and in these fields fill the
entire universe. So are they related to space, like if
if space grows, these fields grow as well. Yes, exactly,
it's a basic part of space, right, you can't have
space without these fields. As far as we know. There's
no fieldless part of space, and every part of space
has these fields. It's like there's a hum at every
(20:40):
point in the universe. There's no quiet place in the
universe exactly. And you might be thinking, well, what if
you have an empty space, maybe all the fields are
just zero. Right, Well, that's the fascinating thing about quantum fields,
right because uncertainty principle, because there's a maximum amount of
information you can have. You can't have quantum field to
be exactly at zero. There's a minimum amount of inner
g they have to have, so they can bubble and
(21:02):
slosh in a way that gives you that uncertainty. Wait wait, wait, um,
there's there's kind of like an inherent energy in these
quantum fields. That's right, Like they're positive. I guess they're
they're not zero exactly. You can't have quantum fields exactly
at zero, and so there's always some energy there and
this is the energy of empty space, right, and that
(21:23):
energy means you have energy and you can create an
electron and depositron which then annihilate themselves back into a
photon or back into something else. So this energy is
always bubbling and frothing. And I feel like this kind
of makes it kind of makes anything possible. Right like before,
when you when you were is there something specific you
want to do? Accomplish with the punting field, you wanted
(21:44):
to do your dishes, get away with something I wanted
to get away with, or or imagine that I can
do you No, What I mean is in the sense
that before, if you were keeping track of all particles,
like if I was made out of the Kevin particles,
then there's sort of no way for me to suddenly
disappear and a you're over there. But now, because everything
is a quantum field, I could choose magically for some reason. Rights,
(22:08):
It's not like because we have quantum fields, there are
no rules, right, There are specific rules for how quantum
fields interact with each other and and how things propagate
through quantum fields, and you know, so we still have
laws of physics. It's not like we're tossing the laws
out the window and you do whatever you like. The
parents are out of town, right um, there's it's just
another way of looking at the universe. Okay, all right,
(22:29):
I guess what I mean is, you know stuff can
appear out of nowhere with these quantum fields. Yes, okay,
it's certainly true that a lot of your intuition is wrong,
and the quantum fields tell us that crazy things could happen,
And then we do the experiments and it's right, right,
quantum quantum field theory seems to be correct. It's a
(22:49):
pretty interesting view of the universe. You know, we think
of it as big and empty, but really there's sort
of like a like a little froth in the background
where a little like simmering bubbling. Yeah, exactly, there's no
place that's actually empty. Either's energy everywhere, and it's it's
filled with possibilities literally, and it's a it's a fascinating
way to look at the universe, and it's led to
a lot of insights. I mean, just like this mathematical
(23:11):
way of thinking about things has revealed things about the
universe we didn't know. For example, like what like the
Higgs boson. The Higgs boson was just an idea. Right
fifty years ago, Peter Higgs and several others said, huh,
what if there was another field? We'll call it the
Higgs field conveniently, And you know, where did you get
this idea? Where did this idea come from? Right? Who
(23:33):
wouldn't want to postulate a field that fills the universe?
And it is named after themselves? Right? Do you think
he named it after himself or people named it after him? Oh,
there's a whole controversy there about who named the Higgs fields,
And it comes down to um who submitted a paper first,
and whether a paper is dated based on the submission
date or the acceptance dage. You know, I mean like,
(23:56):
did Higgs write in his paper I'm going to call
this the Higgs field or did you say it's the
age or b? And then that somebody said, oh, that's
the field Higgs was talking about. Yes, somebody later referred
to it as the Higgs field because Higgs paper has
the earliest date on it. But he actually submitted his
paper after some other folks. Their paper had a later
date on it because the paper had the acceptance date
(24:18):
on it, not the submission date. So somebody later gave
Higgs credit, maybe inappropriately. Okay, so you're saying that these
fields are not just kind of need to think about,
but they've actually led to real discoveries and real understanding
of the universe. Yeah. It was a guy named Steve
Weinberg who read Higgs paper. He was looking at these
fields and he was thinking, thinking, there's a mystery here,
(24:40):
there's a pattern here that doesn't quite work, and that
comes from trying to unify the fields. We've talked on
other podcasts about how the electromagnetic field and the weak
nuclear field, Right, those two forces are actually parts of
the same thing, and they're very similar. But the difference
is that the photon, the thing that moves the electromagnetic field,
has no mass, right, It's it's massless. And the thing
(25:03):
that moves the weak nuclear force are the w n
z bosons. They're really heavy. So Weinberg was like, if
these are two parts of the same thing, how come
one has no mass and the other one has a
huge amount of mass? Right? What could do that mathematically?
Like theoretically, how could you make that happen? And the
what he found was the simplest way to do that,
(25:24):
the easiest, the clearest, like the without adding the minimal
number of moving pieces was to add one more field.
And so he read that paper by Higgs and he thought, Aha,
that is just the field we need. So he said,
if you add this field, and it explains this mystery
why photons have no mass and why the w z
have a lot of mass, But it, you know, creates
(25:45):
another field that feels the universe. So let's go see
if that's real. And but what's interesting is that there
were other people positing other fields, right, Like, he wasn't
the only one. He wasn't the only one. Other people
had similar ideas, and then there are other totally competing ideas,
you know, for ways to solve that mystery with other
different fields. Yeah, exactly. So like I could say, hey,
there's a horhe field that permius everything. Yeah, you could,
(26:08):
and I would be a physicist. Boom, you're a physicist
right here today on the podcast and deputize you. Yeah. Alright,
So if you wanted to propose a field, they would
have to solve a problem, right, like why this field
and not some other fields? And you'd have to provide
a way for us to check, like what in what
experiment could we see the Jorge particle, right, which is
(26:30):
an excitation of the Jorge field, right, and the same
as the Higgs boson is an excited state of the
Higgs field. Right. You have to provide some way for
us to do that, and Peter Higgs did. He's like, oh, well,
if you smash protons together this energy, you should see
a certain number of Higgs particles. All right, So, um,
i'll table that for my next career after we have
a podcast host in a world where cartoonists try to
(26:54):
be physicists. Before we keep going, let's take a short break. Um, okay.
So yeah, it's it's like it's like, really the basic
(27:14):
theory of everything, you know, matter, light, forces, energy, any
kind of everything out there, we describe it using quantum fields.
Almost everything is there? Yeah? Is there something we don't
describe with quantum fields? Yeah, And it's always the same thing.
It's the black sheep of physics. It's gravity. It's quantum
(27:35):
field theory describes matter, it describes electromagnetism, it describes the
weak nuclear force, it describes the strong nuclear force. It
even can incorporate special relativity, meaning we understand what happens
when electrons go super duper fast close to the speed
of light. Right, But quantum field theory is easiest when
space is flat. I mean, we can do quantum field
(27:57):
theory and curved spaces, but it gets really nasty in space.
Getting curved is exactly what general relativity says will happen.
So what quantum field you're saying, don't work in space
that is not flat, like, it only works in flat space.
Not exactly. We can do it, but it's not easy.
It's not a lot of fun. Why not? Why not? Um,
(28:21):
it's a no, it's a great question. It's a great question.
So the issue is more about figuring out how to
get quantum field theory, to explain that curvature, to generate
that curvature, to get a quantum field theory description of
how space gets curved. Like, I like your space curves
or contracts. What does that do to the quantum field?
Doesn't it just squishes it or bends it? Oh? Yeah,
(28:42):
you're right, it just squishes it. Thanks. We just solve
that problem, all right, Um, check that off the list
of modern physics mysteries. Nobel Prize please, Yeah, the squish function.
We'll decide this function. Um. I think also the larger
problem is that we don't know how to describe gravity
in terms of a quantum field. Right, electromagna autism and
all these other forces we can describe as oscillations in
(29:03):
the field. Right, and that fields associated with its own particle.
The photon is is the particles is associated with the
field for electromagnetism, the gluon is the particle associated with
the field. For the strong nuclear force. We have never
been able to describe gravity in terms of a quantum field,
like a gravitational field field space and has a particle
associated with the graviton. We try to do that. We
(29:27):
try to do those theories and write them down, but
you get crazy answers, you get infinities where you should
get reasonable numbers, and just doesn't work on and so
even if you came up with the gravity quantum field
and the graviton, it's still you're saying by itself, it's
not consistent even in flat space. That's right, it's um.
We can't make those theories work. I mean, people have tried,
and people are trying, and they're writing down theories of
(29:49):
quantum um gravity, but those theories don't make testable predictions
that make sense. You know, They predict infinities. You know,
what is the force between these two particles? Infinity? How
much mass does this thing have? Infinite? So it makes
predictions which your nonsense, and we haven't been able to
fix them mathematically. What if it does have infinite masks?
No wonder, I feel so sluggish today, I have infinite masks.
(30:12):
Um alright, So quantum fields they PerMIATE everything. They describe
everything that we know about almost except gravity, except gravity,
and and and they're amazingly accurate, like you're you're telling
me earlier. They can predict things up to like ten
(30:33):
decimal places. Yes, exactly, it's super accurate. Like if you
exclude gravity, we can do these experiments and we can
check them and we get bang on the right answer
to as far as we can measure. You know, it's
a kind of thing that makes me wonder if we
really have pulled back the curtain of nature and seeing
the way the world really works. You know, yeah, yeah,
that sort of makes me all wonder. You know, if
(30:54):
this is the way the universe works? What makes these fields? Like,
what's what's their origin? Where do they come from? You
just never satisfied, are you, Jorge? We explain matter in
terms of particles. We explained particles in terms of fields,
But you're like, I want more. What makes up the fields? Yeah?
How far? How far does the rabbit hole go? Yeah?
I mean we've explained the way matter works in terms
(31:16):
of particles, and particles work in terms of fields and so,
and then of course the next natural question is you
know what makes the fields? Are the fields actually just
something else? Right? Uh, the wiggling of strings or you know,
the dancing of tiny puppies or something. We don't know,
and we don't know. If we get that answer, if
there's not another question behind it, right, it goes even deeper.
(31:37):
Is there an end of this rabbit hole? We have
no idea. Frankly, I hope not. I think the answer
is clear. It's made to Glorian's obviously making absolutely. Yeah,
that was definitely a documentary. So you know, the next
time you are out walking around in the world and
you look up at the sky and you are amazed
at how beautiful things are, remember that deep down underneath
(31:59):
it's a hot, sasty, frothing mess of quantum fields, oscillating
and interacting and bouncing against each other and doing crazy
calculations just to make your everyday world work for you. Yeah,
I like to think of it more as happy fields,
maybe not so like nasty What if they're happy fields? Happy?
What's happy about these fields? They're like zinging and zinging
and interacting with each other, and they're like never resting,
(32:21):
you know, they're they're not like slow lingorious lazy fields.
You know, these are hyper fields. But it's interesting. I
think it sort of makes me think that maybe in
a way, we are all connected, you know, if we're
all just vibrations in these mysterious quantum fields of stuff,
(32:42):
we're all sort of part of all We're all connected,
you know, we're all part of part of the same
stuff that the universe is made out of. That's right, Me,
you and Kevin, who are all really the same, all
the Kens, all of them, all the Kevin's, We are
all the Kevin's. Basically, that's my new religion, the Church
of Kevin to the Church of the Flying Kevin Monster.
(33:02):
Now we are all oscillations in the same universe expanding fields.
That is true. All right, Well, I hope you enjoyed
that quantum field discussion. Thanks for tuning in, And if
you have some crazy concept in physics you'd like us
to break down, send it to us at Feedback at
Daniel and Jorge dot com. Or if your name is Kevin,
we have reserved an email address for you, which is
(33:24):
Kevin at Daniel and Jorge dot com. That's right, and
if you have secrets to the universe, Kevin, please send
them to us at that address. See you next time.
Thanks for listening. If you still have a question after
(33:45):
listening to all these explanations, please drop us a line.
We'd love to hear from you. You can find us
at Facebook, Twitter, and Instagram at Daniel and Jorge that's
one word, or email us at Feedback at Daniel and
Jorge dot com. One
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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