Shadowing Practice: Physicist Brian Cox explains quantum physics in 22 minutes - Learn English Speaking with Video

I think it's important to say

that there aren't different rules of the game in the subatomic world and the world that we observe.

This world of common sense, let's say, that we perceive.

And it's pretty well understood, I would say it's well understood,

how the world that we see emerges from this rather strange but well -defined behaviour that we see in the subatomic world.

And it's not only a subatomic world, by the way, we have an increasing number of quantum technologies that are really based on this behaviour,

the quantum computers being a good example.

And so you see that this is not just something that you can say, well, we don't need to think about it really, because it's in the world of atoms,

because we're using that behaviour now in technologies and so

so it really does become a an important theory to try to to understand

why is it important that we seek to solve the mysteries of quantum physics

you could argue

that even today the interpretation of what the theory is telling

us about the nature of reality itself is not universally agreed upon

One of the big changes actually that's happened in teaching quantum mechanics in universities over the last few decades is

that it was always when I learned it, so back even in the 1990s, it was common to teach it historically.

So you go through the things that we've talked about, you go through the photoelectric effect and the structure of atoms,

you get to Niels Bohr and his early explanations of how atoms might work,

following on from Ernest Rutherford in Manchester detecting the atomic nucleus.

And so this idea that an atom is a nucleus, a dense positive charge, it wasn't known exactly what the structure was at

that time with electrons let's say orbiting in inverted commas around it

so that there's a picture of almost like a solar system

but it was known that doesn't work

because you have charged particles moving in the vicinity of other charged particles

and that means that they radiate and they would not be stable

and so there's all these things going on confusion

and then Bohr suggests that electrons can only take certain energies

which we now call orbitals around the atomic nucleus and all this stuff is going on.

And it used to be that we would teach it like that in university.

But if you do that, you pick up all the confusion, the confusion, decades and decades of confusion

that these great physicists felt in trying to come to terms with this counterintuitive picture of the world.

So now I think it's more common in universities to start with the theory as we understand it today and just say, well, this is the way the world works.

And perhaps the best introduction would be to think of a property of particles called spin.

So you might call these things a qubit.

So what is a qubit?

So you think of a coin which you would toss in the air and it can be either heads or tails.

So that's a kind of an intuitive picture of the world.

This thing is either heads or it is tails.

Now a quantum coin could indeed have the property

that it would be heads or tails but the difference between quantum mechanics

and classical theory is that an object like that a coin,

a quantum coin, can also be in what we call a superposition of heads and tails.

So that means that it can be in a state where it is let's say

if we observe the thing we'll talk about that a bit later

but it can be in a state where it could be 30 heads

and 70 tails or 40 heads and 60 tails

or any combination any mixture of heads and tails and

that is a perfectly legitimate description of the state of the configuration of this thing.

Just to give you a sense of a real physical object that would behave that way,

particles like electrons for example have a property called spin which can be up or down, it's like heads and tails.

But that's the key thing that objects like electrons can not only have definite values of some property,

some thing that you can measure but they can be in a mixture of those things and it's not a probability

theory in the sense that we would usually think of probability theories

so usually we'd say well there's a 50 chance it's going to rain tomorrow

and why do we say that where we would say such a thing it's

because we have incomplete knowledge of the system in this case the weather And so we have incomplete understanding of where,

I suppose, at the most basic level, all those water molecules are in the clouds and so on.

But we don't have enough knowledge to precisely calculate what is going to happen.

And so we assign probabilities to it, which that reflects our ignorance of the situation.

The key difference in quantum theory is that these probabilities are fundamental.

They are fundamental to the description of nature.

So it is not the case that if we have an electron in some kind of configuration,

then our theory predicts probabilities because we don't quite know exactly how this thing is configured.

The probabilities are intrinsic to the theory itself

and pretty much all of the the intellectual challenges

and the confusion around quantum mechanics comes from that very simple property

if you look at pretty much any book on quantum mechanics there is one experiment

which you can describe it's a very simple experiment

which encapsulates all the uh I was going to say weirdness

but it's all let's say all the properties of the quantum world it's called the double slit experiment

and by the way i'll strongly recommend i think it's almost

universally accepted the best description of the double slit experiment is

freely available it's in the Feynman lectures volume three first chapter

and and i've read quantum mechanics textbooks that um

that say go away

and read the first two chapters of the Feynman lectures on physics volume three

because it's all in there can't be done any better so i could recommend that if you find this interesting.

The double slit experiment is essentially, let's say you have something that will emit, let's say electrons, so particles,

electrons, electron gun that emits particles, and then you have a barrier that has two slits cut in it and a screen.

So that's the setup of the experiment.

So we have something that emits electrons, two slits, cutting a screen, and a detector, another screen, that the electrons will hit.

So you fire the electrons out.

So what will that look like?

Well if you think of the electrons as just little particles, little bullets let's say, that are emitted from this gun,

then you would imagine that the electrons can go through one slit or the other one, depending on how they come out, and you can imagine that they might get deflected around a little bit

when they go through the slits

but basically on the screen you would expect most of the electrons to appear opposite one

or the other of the slits with maybe a bit of a spread

because they rattle around a bit when they go through

so you get lots here lots here and pretty much none in the middle

but that's not what you see what you see is a

very clear pattern on the screen you see sort of stripes

a stripe on the screen where you get lots of electrons

and then a stripe where you get very few or none

and then another stripe where you get lots

and then a stripe where you get very few or none and then another stripe and then very few or none.

So you get this stripey pattern.

That pattern is exactly the same pattern that you would get if you sent waves through the slit.

Let's say water waves, any kind of waves, then it's easy to understand.

100

Because what's happening then, and this fellow, physicists knew this back in the 1700s,

101

right, is that you can consider each slit as a source of new waves.

102

And the waves come out, and waves have the property that they can interfere with each other.

103

So you can get the peak of one wave arriving at the screen from one slit, and a trough of a wave arriving at the screen from another slit

104

and if everything's lined up correctly the peak and the trough cancel out

105

and you get nothing

106

so you get this property where where something from each slit it's very easy to understand

107

if it's a big extended wavy thing

108

lines up in such a way that it cancels out

109

and then it could line up in such a way that it

110

reinforces and you get a big disturbance there and then it cancels out again and then it reinforces again.

111

So you can imagine this stripy pattern on the screen, that's what you get with waves.

112

The fact that you get it from particles is interesting, but here's another interesting thing.

113

You still get that pattern if you send one particle at a time through the slips.

114

So it is, and let me use my language carefully I was going to say it is as

115

if the electron can somehow explore both paths just like a wave can and then interfere with itself.

116

to control where it lands on the screen, as if is something that people might object to.

117

Many physicists would say no, it does.

118

So the statement is that the electron explores both roots at the same time,

119

at once, let's say, on its root from the electron gone through the slits to the screen.

120

So that's a very strange picture of reality.

121

We surely think of particles as following definite paths

122

and it might be that you don't know quite

123

which path it's going to take but surely you would say in reality it will go one route or the other route.

124

But that experiment which I emphasize has been done now many times, tells us that nature is not like that.

125

It tells us that the electron must,

126

in some sense, explore all routes on the way from the gun to the screen.

127

And so the question then becomes, well, what do I mean by in some sense? what you'll

128

see in the Feynman lectures is he gives you two pictures of how to think about physics.

129

One is he gives you the way that you would calculate what you're going to see on the screen.

130

And that's really simple, as Feynman points out.

131

So what you can do is you can assign,

132

calculate what's called a complex number for every route that the particle, the electron, can take from gun, through the slits, to the screen.

133

So every route, every path it can possibly take.

134

A complex number, for those that don't know about complex numbers, can be pictured as a little clock face.

135

So a complex number has a clock hand, there's a length of the clock hand, and there's the time on the clock face.

136

And you can calculate how those clock faces kind of evolve

137

and change and spin around from the moment the electrons emitted to the moment it hits the screen

138

and the prescription is very simple you can calculate what those clock faces look like what those complex numbers are

139

and every point on the screen you have to take them all every possible path to

140

that point and just add them up

141

and the length of the clock hand gives you the probability

142

to find the electron there it's actually the squared length of the clock hand

143

but whatever it's the length of the hand that's it

144

so you can see

145

that you have this property you can have interference you could have one clock arriving at 12 o 'clock

146

and one clock arriving at six o 'clock and they cancel out

147

and so on you just do that you calculate it then you get the right answer

148

so it's a very very simple prescription but i suppose the problem comes

149

when you say well what does it mean does it really mean is it just calculation

150

or is it is this just mathematics or does it really mean that the electron explores every possible route?

151

By that, I mean every possible route.

152

You might consider it going to the Andromeda galaxy and back.

153

Every possible route on its journey from when it's emitted to when it's detected.

154

And I think many physicists now would say that that is a correct description of reality.

155

The particle does.

156

But I just wanted to emphasize that the mathematics, the way that you make the calculation, is pretty simple.

157

It's a prescription for making a calculation and you get the right answer to the experiment.

158

The problem with quantum mechanics, I suppose, is when you try to interpret what the calculation means for the nature of reality.

159

I think it's important to say

160

that there aren't different rules of the game in the subatomic world

161

and the world that we observe this world of common sense let's say

162

that we perceive there aren't different rules

163

and it's pretty well understood I would say it's well understood how the the world

164

that we see emerges from the from this rather strange but well -defined behavior that we see in the subatomic world.

165

And it's not only the subatomic world, by the way.

166

This is now, maybe you could have argued 50 years ago that this is just our philosophy, it doesn't really matter, whatever.

167

But now we have an increasing number of quantum technologies that are really based on this behavior,

168

the quantum computers being a good example and so you see

169

that this is not just something

170

that you can say well we don't need to think about it really

171

because it's in the world of atoms and it's all a bit whatever

172

and we but and we can just do some calculations

173

because we're using that behavior now in technologies and so

174

so it really does become a an important theory to try to to understand Now, you go back a few decades,

175

then I think you could say that the interpretations of quantum mechanics are very interesting

176

and very important because we're talking about the nature of reality.

177

But you might say, well, it doesn't really matter so much practically, right?

178

Now, I have a lot of colleagues in physics who would, I think, rightly hate that description because what we're trying to do is understand reality, what physics is.

179

But now, particularly, I think, with the possibility of building quantum computers,

180

this attempt to understand how large systems of quantum mechanical objects behave is becoming extremely important

181

because a quantum computer is a device which is built out of qubits.

182

Remember a qubit, an example would be an electron which has this property that when you make an observation of the spin,

183

let's say, of this electron it behaves like a coin.

184

It can be up or down, heads or tails, however you want to describe it.

185

But that thing can also exist in a superposition, a combination of these things.

186

It's a perfectly valid configuration and you you use that.

187

That's the kind of property that you use in building a quantum computer.

188

You can also then ask the question, well what happens if I get another one, two electrons together?

189

These can be in what's called an entangled state.

190

So then you have a much richer structure of this physical system.

191

So an example of an entangled state, a very famous thing called a bell state, would be where you set these things up.

192

So the system of these two qubits, let's say they're up and down these spins, right?

193

So I can have the state up, down, plus, down, up, like that.

194

A complete description of this state, up, down, plus, down, up.

195

What does that mean?

196

So let's say I take one of these electrons and separate them.

197

It's a very famous paper written by Einstein, Podolsky and Rosen that first considered this in the 1930s, and they get very upset by the behaviour.

198

So we've got a system, a state, and it's up -down plus down -up, let's say.

199

And I separate these electrons.

200

I take one to, let's say, to Pluto and leave one on planet Earth.

201

So what's the description of this thing in that state?

202

Well, it's got, But in the way I described it, there's a 50 -50 chance that when I make a measurement of this electron,

203

the up or downness of it, then there's a 50 -50 chance it'll be either up or down.

204

And the same for the other one.

205

That's what that state means.

206

But if it's up, down, plus down, up, then it means that if I make a measurement of that one, if I say, well, OK, I know what that is.

207

It's up.

208

The other one has to be down.

209

up, down, or down, up.

210

It can't be up as well.

211

Same for the other one.

212

If I go to Pluto and have a look at this one, and it's down, then this one definitely is up, right?

213

So this is called quantum entanglement.

214

And the reason it bothered Einstein and others is it would appear that something is instantaneously changing.

215

And it's not just your knowledge of the system that's instantaneously changing it would seem

216

that the system itself is instantly configuring itself when you make some measurement

217

so you might say well this is nonsense there must be something else

218

and it turns out that as far as we can tell um

219

that a nobel prize was awarded for some of this research

220

a few years ago then no there's nothing hidden there this is this is the way

221

that the system is but you think about

222

that system of two qubits i think about it

223

so there are you've got these two things which can be up

224

or down there are four possible combinations of that of

225

that system you can have up down down up up up

226

or down down four for the two qubit system for a three qubit system you think about it ups

227

and downs you'll find out there are eight possible combinations

228

and all mixtures of them for four qubits then it's two to the power four there's 16 possible combinations.

229

We're talking about building quantum computers now in which we have 100,

230

200, 300 qubits, all in principle entangled together.

231

The number of possible descriptions of that system then, you have numbers that describe it.

232

If there are 100, it's 2 to the power of 100.

233

different configurations and any mixture of those things that are states of the system.

234

So pretty soon 2 to the power 100 for 100 qubits.

235

What's the number of atoms in the universe?

236

If you had 2 to the 500 you'd far exceed 500 qubits.

237

The number of numbers you need to describe that system exceeds the number of atoms in the observable universe.

238

But it's a thing

239

that we can build we can build just about we're not

240

far off being able to conceive at least of a network

241

of 500 qubits they're physical things they're kind of like

242

that big some of them right you go 500 them in this room um

243

so the the power that's hidden in the description of a system like

244

that is immense and the thing that a quantum computer does is it uses

245

that power some of that power some of that vast computational

246

or configurational power of the thing very very difficult to do

247

and we've not been able to do it particularly well at

248

the moment you'll read many papers online where obviously companies like

249

google microsoft ibm are investing a lot of money in these devices

250

because potentially they are that they can carry out computations

251

that no conceivable classical computer could make within the lifetime of the universe

252

because of this tremendous freedom in the description of the structure of the system

253

so quantum mechanics and quantum entanglement these properties of matter of nature are becoming very real

254

because we're getting we're beginning to be able to access this

255

this tremendously complicated configuration space to do useful things to make calculations that are useful to us.

📺 Mismo canal

Your genes affect your education. Here’s why that’s controversial. | Kathryn Paige Harden

IELTS PrepTOEFL PrepUniversity Students

Cornel West: How Intellectuals Betrayed the Poor | Big Think

IELTS PrepTOEFL PrepUniversity Students

A mind-blowing explanation of symmetry | Frank Wilczek for Big Think

IELTS PrepTOEFL PrepUniversity Students

Einstein’s beef with quantum physics, explained | Jim Al-Khalili for Big Think

IELTS PrepTOEFL PrepUniversity Students

How do elite performers automate their habits? | Wendy Wood

Business EnglishUniversity StudentsWorking Adults

Why softness beats stress | Giulia Enders

Business EnglishUniversity StudentsWorking Adults

Who decides what is socially “normal”? | Christine Emba

Daily ConversationUniversity StudentsWorking Adults

How our expectations shape what we see, hear, and feel

Business EnglishUniversity StudentsWorking Adults

Harvard negotiator explains how to argue | Dan Shapiro

Business EnglishUniversity StudentsWorking Adults

Curiosity Is a Superpower — If You Have the Courage to Use It | Big Think

Business EnglishDaily ConversationUniversity Students

How Einstein changed time forever | Jim Al-Khalili for Big Think

IELTS PrepTOEFL PrepUniversity Students

Keep your brain from declining after age 30

Business EnglishUniversity StudentsWorking Adults

A neuroscientist’s guide to reclaiming your brain | Nicole Vignola

Business EnglishUniversity StudentsWorking Adults

Expand your perception. Change your life. | Dr. Jill Bolte Taylor

Business EnglishUniversity StudentsWorking Adults

Why humans need fiction, according to neuroscience

IELTS PrepTOEFL PrepUniversity Students

Love is a skill, not a feeling | Alain de Botton: Full Interview

Daily ConversationUniversity StudentsWorking Adults

✨ Recomendar Video

109 oraciones

How ELECTRICITY works - working principle

Business EnglishUniversity StudentsWorking Adults

156 oraciones

How Quantum Batteries Break Every Rule of Charging

Business EnglishUniversity StudentsWorking Adults

105 oraciones

The Law of Resonance: You Never Meet Anyone by Chance

Business EnglishUniversity StudentsWorking Adults

67 oraciones

Elon Musk on Education

Business EnglishDaily ConversationUniversity Students

47 oraciones

Essence of linear algebra preview

Business EnglishUniversity StudentsWorking Adults

131 oraciones

Unit Conversion & Significant Figures: Crash Course Chemistry #2

Business EnglishUniversity StudentsWorking Adults

200 oraciones

Force Your Brain to Think Like a Genius | Richard Feynman

Business EnglishUniversity StudentsWorking Adults

162 oraciones

Crypto Agility Explained: Protect Data from Quantum Computing Threats

Business EnglishUniversity StudentsWorking Adults

279 oraciones

LET THERE BE... Voltage? | Maxwell's Equation #2 Explained for Beginners

Business EnglishUniversity StudentsWorking Adults

195 oraciones

What is This $3BN Machine Under New York?

Business EnglishUniversity StudentsWorking Adults

193 oraciones

Semiconductors explained in 16 mins | Chris Miller

Business EnglishUniversity StudentsWorking Adults

¿Qué aprenderás?

Con este video, mejorarás tu capacidad de seguir conversaciones técnicas en inglés, especialmente al hablar de temas científicos como la física cuántica. También practicarás la escucha activa para captar ideas complejas y aprenderás a estructurar explicaciones claras, ¡ideales para debates o presentaciones! Además, la técnica de shadowing (o "shadowspeaks") te ayudará a sincronizar tu pronunciación con la de un hablante nativo, logrando fluidez en poco tiempo.

Escucha estos sonidos

En el diálogo, nota cómo se unen palabras como "it's important to" (se dice casi "itsimpornto") o "we don't need" (se reduce a "wedon'tneed"). Observa también la conexión entre "quantum mechanics" y "in universities", donde el sonido final de "mechanics" se funde con el inicial de "in". Estas reducciones y enlaces son clave para entender el inglés hablado cotidiano y para que tu speech suene más natural.

Háblalo como un nativo

Para imitar el ritmo y el énfasis del hablante, presta atención a las palabras clave: "superposición", "qubit", "experimento de la doble rendija". Éstas se dicen con mayor énfasis y duración. Practica la técnica de shadowing: reproduce un fragmento corto, deténlo y repítelo inmediatamente, intentando igualar la velocidad y la entonación. Usa frases como "the probabilities are fundamental" para trabajar la fluidez. Recuerda: el shadow speak no es solo repetir, sino sentir el flujo del idioma. Con ejercicios diarios de 5 minutos, verás cómo tu pronunciación y confianza mejoran.

Aprende inglés con videos y aprovecha cada oportunidad para practicar. El shadowing es una herramienta poderosa: transforma conversaciones en clases prácticas y haz que el inglés se convierta en tu segunda lengua. ¡Empieza hoy y descubre cómo cada repetición te acerca a la fluidez!

Gramática en este vídeo

Las estructuras que más usa el hablante, con las palabras exactas del vídeo:

Estructura	En el vídeo
Oraciones condicionales if + oración, will/would + verbo — una condición y su resultado	if we observe the thing we'll talk
Voz pasiva be + participio pasado — importa lo que ocurre, no quién lo hace	are really based · wasn't known · was known
Present perfect have/has + participio pasado — una acción pasada que sigue importando ahora	we've talked · have charged · i've read
Oraciones de relativo who / which + oración — información extra sobre una persona o cosa	spin which can · device which is · electron which has

¿Qué es la Técnica de Shadowing?

Shadowing es una técnica de aprendizaje de idiomas respaldada por la ciencia, desarrollada originalmente para la formación de intérpretes profesionales y popularizada por el políglota Dr. Alexander Arguelles. El método es simple pero poderoso: escuchas audio en inglés nativo y lo repites en voz alta de inmediato, como una sombra que sigue al hablante con solo 1-2 segundos de retraso. A diferencia de la escucha pasiva o los ejercicios de gramática, el shadowing obliga a tu cerebro y músculos de la boca a procesar y reproducir simultáneamente patrones de habla reales. Las investigaciones muestran que mejora significativamente la precisión de la pronunciación, la entonación, el ritmo, el habla conectada, la comprensión auditiva y la fluidez al hablar, convirtiéndola en una de las metodologías más efectivas para la preparación del IELTS Speaking y la comunicación en inglés en el mundo real.

Técnica de shadowing: lee la guía completa paso a paso →

Shadowing Practice: Physicist Brian Cox explains quantum physics in 22 minutes - Learn English Speaking with Video

What science can’t answer, according to physicist Jim Al-Khalili | Big Think

Why successful people set habits, not just goals | Wendy Wood

Hit peak performance with the power of habit | Wendy Wood

What if quantum physics could eradicate illness? | Jim Al-Khalili for Big Think

Your genes affect your education. Here’s why that’s controversial. | Kathryn Paige Harden

Cornel West: How Intellectuals Betrayed the Poor | Big Think

A mind-blowing explanation of symmetry | Frank Wilczek for Big Think

Einstein’s beef with quantum physics, explained | Jim Al-Khalili for Big Think

How do elite performers automate their habits? | Wendy Wood

Why softness beats stress | Giulia Enders

Who decides what is socially “normal”? | Christine Emba

How our expectations shape what we see, hear, and feel

Harvard negotiator explains how to argue | Dan Shapiro

Curiosity Is a Superpower — If You Have the Courage to Use It | Big Think

How Einstein changed time forever | Jim Al-Khalili for Big Think

Keep your brain from declining after age 30

A neuroscientist’s guide to reclaiming your brain | Nicole Vignola

Expand your perception. Change your life. | Dr. Jill Bolte Taylor

Why humans need fiction, according to neuroscience

Love is a skill, not a feeling | Alain de Botton: Full Interview

How ELECTRICITY works - working principle

How Quantum Batteries Break Every Rule of Charging

The Law of Resonance: You Never Meet Anyone by Chance

Elon Musk on Education

Essence of linear algebra preview

Unit Conversion & Significant Figures: Crash Course Chemistry #2

Force Your Brain to Think Like a Genius | Richard Feynman

Crypto Agility Explained: Protect Data from Quantum Computing Threats

LET THERE BE... Voltage? | Maxwell's Equation #2 Explained for Beginners

What is This $3BN Machine Under New York?

Semiconductors explained in 16 mins | Chris Miller

¿Qué aprenderás?

Escucha estos sonidos

Háblalo como un nativo

Gramática en este vídeo

¿Qué es la Técnica de Shadowing?