From Transistors to Quantum Computers

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From Transistors to Quantum Computers

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Taking you through all the physics from how transistors work, to how a quantum computer works and how to make one in practice including quantum cooling to near absolute zero

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6:00
1

How Does a Transistor Work?

by Veritasium 466,560 views

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Supported by TechNYou: http://bit.ly/19bBX5G
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How does a transistor work? Our lives depend on this device. When I mentioned to people that I was doing a video on transistors, they would say "as in a transistor radio?" Yes! That's exactly what I mean, but it goes so much deeper than that. After the transistor was invented in 1947 one of the first available consumer technologies it was applied to was radios, so they could be made portable and higher quality. Hence the line in 'Brown-eyed Girl' - "going down to the old mine with a transistor radio."

But more important to our lives today, the transistor made possible the microcomputer revolution, and hence the Internet, and also TVs, mobile phones, fancy washing machines, dishwashers, calculators, satellites, projectors etc. etc. A transistor is based on semiconductor material, usually silicon, which is 'doped' with impurities to carefully change its electrical properties. These n and p-type semiconductors are then put together in different configurations to achieve a desired electrical result. And in the case of the transistor, this is to make a tiny electrical switch. These switches are then connected together to perform computations, store information, and basically make everything electrical work intelligently.

Special thanks to PhD Comics for awesome animations: http://bit.ly/16ZXcVY

And thanks to Henry Reich and Vanessa Hill for reviews of earlier drafts of this video.

Music: Kevin MacLeod (incompetech.com) Decisions
8:49
2

Transistors & The End of Moore's Law

by 2veritasium 151,253 views

How does a transistor work? And when will Moore's Law break down?
Supported by TechNYou - check out their great series on the scientific method: http://bit.ly/19bBX5G

Thanks to A/Prof Morello and UNSW. Find out more here: http://bit.ly/17wZ7lt
6:47
3

How Does a Quantum Computer Work?

by Veritasium 592,211 views

For more on spin, check out: http://youtu.be/v1_-LsQLwkA
This video was supported by TechNYou: http://bit.ly/19bBX5G
A quantum computer works in a totally different way from a classical computer. Quantum bits or 'qubits' can exist in a superposition state of both zero and one simultaneously. This means that a set of two qubits can be in a superposition of four states, which therefore require four numbers to uniquely identify the state. So the amount of information stored in N qubits is two to the power of N classical bits.

Thank you to Andrea Morello and UNSW. For more info, check out: http://bit.ly/17wZ7lt
8:44
4

What is Quantum Mechanical Spin?

by 2veritasium 61,434 views

This video extends How Do Quantum Computers Work: http://youtu.be/g_IaVepNDT4
Prof. Morello explains why spin does not mean the particle is actually spinning. Subatomic particles like the electron, neutron, and proton have spin, which means they act like tiny bar magnets. This can be used in quantum computing applications.

We thank the UNSW School of Physics Demonstration Unit for providing the double pendulum.
9:57
5

Quantum Cooling to (Near) Absolute Zero

by 2veritasium 189,406 views

Getting down to liquid helium temperatures (4K) may be fairly straight forward, but cooling below that requires taking advantage of quantum phenomena. In this video Associate Professor Andrea Morello from the University of New South Wales explains how 'zero-point motion' makes it possible to use Helium-3 and Helium-4 in a dilution fridge to get down to only thousandths of degrees above absolute zero.
It is this technique which is used to cool the MiniGrail at Leiden so that it can act as a gravitational wave antenna.
For more on Dr. Morello, see: http://bit.ly/17wZ7lt
7:51
6

How To Make a Quantum Bit

by Veritasium 177,420 views

Transistors to Quantum Computer Playlist:
This episode supported by audible.com: http://bit.ly/ZJ5Q6z
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Silicon-28 sphere: http://bit.ly/10J1G2o

We have looked at how a transistor works, the fundamental unit of classical computers, and how a quantum computer works in theory, taking advantage of quantum superposition to hold exponentially more information than classical computers. Now we look at the practical side of making a quantum bit, or qubit. How do you put it in a state where it is stable? How do you read and write information on it? These processes are described for a solid state qubit - a phosphorous atom in a silicon crystal substrate. Both the electron and the nucleus of the phosphorous atom can be used as qubits.

Thanks to A/Prof. Andrea Morello: http://bit.ly/17wZ7lt

Thanks to Henry Reich (MinutePhysics) for pushing me to make the explanations and visualizations clearer.