At the University of Colorado, an institution called CULLA, and I'm also associated with

the physics department there.

Very good.

So the lecture today is a kind of introduction to a subject which is an analogy of optomechanics,

the topic of our school.

I called it optomechanics and I'll discuss why I called it optomechanics a little bit

later.

But essentially this is the analogy of optomechanics where instead of having something that you

usually consider optical light, we replace that with microwave electrical signals that

run through wires and cables and transmission lines, and there's still mechanics involved.

So the image on the slide is a kind of electromechanical device.

It's some superconducting circuits with mechanically compliant vibrating things.

And today what I wanted to do is give you the machinery just to talk about something

like this to do the kind of basic calculations.

But before I do that, I'll describe a little bit about what I think is sort of distinct

and interesting about electromechanics.

And to do that, I'll think about why it was that optomechanics kind of became a topic.

Why did we become interested in it?

And at least from my perspective, I think part of that has to do with the special role

that mechanics and mechanical oscillation plays in the physical sciences, in measuring

the physical sciences.

In particular, if you think about the commercially available optomechanical instrument,

you can go out and buy, is the atomic force microscope.

The sharp tip sitting at the end of some flexible cantilever that you scan over a surface,

what happens is you transduce the feeble and very small scale forces of some surface into

a deflection of a cantilever that you read out very sensitively by bouncing a laser beam

off the back of that cantilever.

And in principle, you need have no more noise in the readout than is just present in the

quantum fluctuations of the light itself.

This is kind of an astounding fact.

So this notion that mechanical oscillators allow us to couple things which are hard and

awkward to measure to something that we like to work with like a laser light field,

that's sort of been a powerful idea.

And that's the commercially available instrument, but our speaker this morning,

Wynand Wazinski, used very sensitive cantilevers to measure tiny, tiny little forces of

normal metal rings in magnetic field, the kind of forces associated with the persistent

currents in those normal metal rings.

And I think that idea, that kind of nanometre concept was probably inspired by work that

a group at IBM has been doing for many years to try to build a magnetic resonance imaging

device with nanometer length scales where the kind of transduction, the conversion of

information about nuclear spin density to something that you could hope to measure is

done by the force, really, really feeble forces.

And you can take this idea further if you look a little bit more broadly.

You can see that if you want to understand something about the phase diagram of superfluid

helium, when it's superfluid, what fraction is superfluid, you can make a little kind

of tortuous oscillator where superfluid sloshes around inside of that object, which you then

read out electrically.

And again, it's the kind of mechanical structure that gives us access to something that would

be awkward to measure in some other way.

I'll get a little bit bigger, and in the end, we're interested in fundamental force of