Monday, October 27, 2008

Emergent Relativity

When I posted the link to the paper on Quantum Criticality and Black Holes, I had a nagging feeling in the back of my mind of reading something on a similar topic a while back. I couldn't quite remember where, and I also couldn't completely rule out that I was simply imagining it.

And viola! I wasn't! Last night when I was about to go to sleep, I suddenly remembered that it might have been something written by Robert Laughlin! So while that kinda ruined my ability to go to sleep immediately, I'm glad that I remembered this morning to look it up, and I found it. It was a speech to honor C.N. Yang's 80th birthday titled "Emergent Relativity".

In it he argued that Relativity is an emergent phenomenon. You'll have to read the paper to figure out how he can make such a claim. But here, he also made the connection between black holes and quantum criticality, just like Sachdev and company.

Of course, Laughlin and other condensed matter physicists such as Anderson and Pines, have always argued for the emergent phenomena as the dominating behavior of our universe. They have continued to argue against the reductionist method of elementary particle physics and string theory/etc. as being the "fundamental" knowledge.

Still, what I definitely like about this Laughlin paper is this particular passage that many people, and sometime even among physicists, often forget:

I believe that physics is an experimental science, and that theory acquires authority by confronting and conforming to experiment, not the other way around. Dealing with a rich experimental record day after day has the additional benefit of giving one a healthy respect for the natural world's ability to surprise and a healthy disrespect for the belief that all things can be calculated from first principles.

Them's fightin' words! :)



Peter Morgan said...

Do you know of the book, "Universe in a helium droplet", Oxford University Press 2003, by Grigori Volovik, available in final draft form from his web-site, There's quite a bit of work trying to make connections between local Lorentz invariance in liquid Helium systems and in QFT.

Stupac2 said...

I'm in a seminar with him right now, and that certainly does sound like something he'd say. It's called "Seminar on theoretical physics" but so far we've only talked about experiments. To be fair it's certainly easier to talk about Fitch-Cronin than the whole universe of CP violation (my topic), but still, it shows his bias. I wonder how it will compare to Lenny Susskind next term.

Ben Lillie said...

It's not just black holes: people have been able to construct super-fluid systems where the excitations have full non-abelian gauge symmetries. Volovik's book is a nice overview. As an approach to fundamental physics, it runs into some serious problems -- e.g. the last time I looked (which was years ago) in the their models fermions and bosons had different speeds of light. Fundamental issues aside, what people have accomplished in actual super-fluid systems is absolutely astounding.