She Says Spacetime Points Are Just Where Fields Meet

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Lucrezia Ravera (0:25)

Physical space-time is really where Fields meet. There are Fields everywhere. That's marvelous and also a bit scary maybe.

Curt Jaimungal (0:34)

Why is it scary?

This is Lucrezia Ravera, a physicist at the Polytechnic University of Turin. She's rewriting quantum mechanics in bundled differential geometry, where the wave function becomes something called a co-cyclic object.

Lucrezia Ravera (0:46)

The time, t, and the space x variables disappear from the picture.

Curt Jaimungal (0:51)

With Jordan François, she's developing the dressing field method. What it does is pull out what's physical without fixing a gauge.

These are cutting-edge techniques. And don't worry if you don't follow all the technicalities. The point isn't to drink from the fire holes, it's to just get wet.

Lucrezia Ravera (1:08)

I tend to have a geometric mind, maybe it's part of just my personality.

Curt Jaimungal (1:13)

On this channel, I, Curt Jaimungal, interview researchers regarding their theories of reality with rigor and technical depth. Today, Lucrezia explains what relationalism is, and how you can't make sense of physics unless you realize that the fields co-define one another, and how this upends our traditional view of space-time.

Lucrezia Ravera (1:32)

The manifold is not there anymore.

Curt Jaimungal (1:35)

Lucrezia, what excites you about physics? How did you get started in it?

Lucrezia Ravera (1:40)

Yeah, well, I'm a curious person, and I like problem solving, so it's one of my skills. I like solving problem, understanding things, and I'm very, very curious, so everything starts from there actually, because physics is precisely the way in which I get to do this. I had at a certain point in my life several options. I was interested in many disciplines, but then I went for physics.

And in fact, I started, for curiosity, I started with my bachelor and master degree in string theory. And precisely because for at least to me, that was entirely new. I did just one course on string theory. So that was entirely new for me. And I was very curious about it.

And after that, I did move on to super gravity with my PhD. And there also, it was again pushed by curiosity to learn new things. And therefore to experiment theoretically, of course, but with new theories. And there, I did super gravity in a geometric way. It is called the geometric approach to super gravity in super space. And this was so because I tend to have a geometric mind, a geometric mindset. And so it was very nice to me to get to know super gravity with this approach. And then I did gravity, alternative theories of gravity, gauge field theory. And finally, my current research that I'm developing now, that is the Dresden film method.

Curt Jaimungal (3:18)

Oh, great. You mentioned you have various curiosities. So what else besides physics?

Lucrezia Ravera (3:24)

Well, precisely because of the fact that you get to try to understand how nature works, to get to understand something about reality. And so that's what's different. I was also intrigued by, for instance, philosophy, in particular, philosophy of physics.

And then also by other disciplines like arts and things like that. But then physics, one, because it's there, that you really have to push yourself, to ask yourself questions, possibly the right questions, which is key, and to try to understand how the world works. At the beginning, I wasn't sure if experimental physics or theoretical physics, it just came to me that choice as the best for me that I could figure in that moment. But after a course, and it was on analytics, analytic mechanics, I said, and I saw for the first time Einstein's equations, also the Einstein notation for generativity, I say, okay, now I want to do theoretical physics. So because, yeah, yes.

Curt Jaimungal (4:27)

You mentioned that you have a geometric mindset.

Lucrezia Ravera (4:30)

Yeah.

Curt Jaimungal (4:30)

What's the difference between a geometric mindset and a visual one?

Lucrezia Ravera (4:34)

That's a hard question because I tend to inflate a bit the two because, okay, maybe because I'm thinking more of a differential geometric mind which and differential geometry has also, at least to me, I don't know if it is because of my mindset, but I think it tends to be very visual also. Like I think of differential geometry, differential geometry of fibrous space. And so you have to, so you have a geometric properties, is a mathematics, is a side of mathematics in which you think with, you deal with the geometry, but also it's very visual. So the, all the objects at play, the mathematics at play has, you got to visualize it somehow. And so that's what I, when I say geometric mind, I mean both when I have to think of physics in mathematical terms, so in the language of physics that is indeed mathematics. And when I do computation, when I have to visualize what's happening somehow, of course, there are things that we cannot truly visualize, but we can have the hints, visual hints somehow, and that's what I mean.