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Q&A: Carver Mead revolutionized computers. Can he do the same for physics?


Carver Mead doesn’t admire complicated things. As far as he is concerned, the bigger challenge is to take a complex system and find a way to simplify it without overlooking any important part of it.

At a time when integrated circuits for computers are diligently painted by the hands of skilled lithographers, microelectronics pioneer Caltech designed a blueprint that makes it easy for anyone to install thousands of transistors on a microcontroller chip. His early 1970s innovation – called very large scale integration, or VLSI – recently won him the prestigious 2022 Kyoto Prize.

VLSI has played an important role in the semiconductor revolution. This has fueled the exponential increase in the number of transistors that can be placed on a chip, which can reduce computer hardware while expanding their capabilities.

After wizarding with the movements of electrons around a microchip, Mead became interested in the basic laws of physics that govern their motion. He took it upon himself to reformulate the rules of electricity and magnetism, which are now taught in the way they were back when they were proposed by James Clerk Maxwell in 1865.

Using more than a century’s worth of modern physics experiments, Mead created a more holistic picture of electromagnetic phenomena. His method is based on quantum physics, which treats electrons, photons and other building blocks of matter as waves and particles.

Mead called the result “collective electrodynamics” and used that term as the title of a “little green book” on the subject he published in 2001. Now a professor emeritus at Caltech, he continues to work on it and other projects.

He spoke to The Times about his journey from computer technology to basic physics.

Can you describe the principles of collective electrodynamics?

Think of the electron as a wave, with a frequency equal to its energy and a wavelength relative to its momentum. A superconductor consists of a large density of electrons, combined with each other so that they form a giant quantum collective state called condensate. It’s like a big electron.

If we make a wire from a superconductor, the expansion of the condensate wave along the wire is called electrical current, and the frequency of the condensate wave is called voltage.

The components of electromagnetism are of quantum origin.

So you say physics is necessary for a change?

Quantum physics was unknown in Maxwell’s day, so the quantum origin of electromagnetic interaction is invisible. Unfortunately, electromagnetic theory is still taught in the ancient way.

What is the biggest difference between the collective electrodynamics and the classical method?

The importance of potential. Electrical engineering, which makes up our modern world, is built on the idea of ​​potential. Many physicists don’t really understand potential – they think it’s a mathematical trick. But really, it’s a very deep concept.

In an electrical circuit, electrons condensate on a wire like water flowing through a pipe. We call the flow of this electric current, and its pressure is called the electric potential, or voltage.

Does collective electrodynamics offer new insights that you can’t get in the basic theory of electricity and magnetism?

For standard items, you get the same answer for both. But there are things that are easier to explain in my approach.

For example, take the quantized flux. That describes how an object flows in a region of discrete quantity. In the ’70s, scientists observed that the magnetic flux around the tiny donut of a superconductor behaved in this way. If you have a set of these, you get a permanent magnet. That’s what a permanent magnet is – a set of small superconducting loops, one in each atom. And they all lined up.

Extending it to two magnets, you can calculate what they do to each other and you get the energy beautiful. By thinking of it as a quantum system, collective electrodynamics gives you the correct answer in a more straightforward way than the classical method. And that’s a deep basic thing you can measure.

Some find it very interesting. But remembering this, the book doesn’t have enough explanation, so people have a hard time following it. Once or twice a year, I get an email from someone saying, “I took what you said in your little green book, and it changed my life.” And then it will be quiet for a year or two.

Are you planning to expand it further?

Yes, I have a hard time working on that.

Do you think it will help to train the next generation of physicists in this new, holistic way?

We make new things in physics all the time. Let’s say, as an estimate, we have a doubling of knowledge every five or 10 years. After some of this, it is no longer possible to educate people, because there are so many new things.

So you really only have two options. One is that you can become narrower and narrower, where you learn more about less and less until you know everything about left. Or you can go back and find that the new knowledge we have allows for a much deeper way to understand the field, and its relationship concepts.

There is a widespread idea that new science brings new innovations. Is this always true?

This is almost unreal.

Most of the things that happen are not the main zeitgeist. It’s what makes people creative and go and try it, and most of it doesn’t work. Most of the things I’ve done don’t work, but sometimes I get one to work. And it feels so good!

What other kinds of innovations have you worked on?

I spend a lot of time working on the best organizational information systems. The most commonly programmed computer – like your laptop or smartphone – that we use today is very wasteful of its resources. It does a simple thing, and it uses a lot of energy to do every simple thing.

We started creating ways in which you could use silicon technology with transistors to mimic the things the animal brain does. If you study the nervous systems of animals, organization is very different from a general purpose computer, and it is much more energy efficient-our brain only needs about 20 watts to run.

Being an emeritus professor allows me time to think more deeply about things, keep up the effort like a little green book, and think about things like what happens to the brain.

This interview was edited for length and clarity.





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