[Doctor Stochastic]

Of course, I discovered in college that the world is really non-deterministic. Else things like this couldn't exist. Sans randomness, these Bose-Einstein condensates don't condense.

Naturally, Brownian motion shows that even a classical system is completely non-predictable (even in principle) if molecules exist.

[VadeRetro]

Naturally, Brownian motion shows that even a classical system is completely non-predictable (even in principle) if molecules exist.

Supposedly the classical physics "arrow of time" is non-reversible, but I always wondered if this isn't still in principle deterministic. In a sealed vaccuum container, you introduce three sealed bottles. Two contain vaccuums themselves, the third is full of gas. You open all the bottles and the gas from one rapidly fills the bigger container. Tah-dah! You cannot tell which bottle the gas came from, so the arrow of time is irreversible, etc.

I tend to think that God or even a really jazzy supercomputer could unravel it. The information is always there at any given time (in the position and momentum of each gas particle) to unravel the previous state of the gas. Never mind how you know the position and momentum of every gas particle. If you do, you know what it last bounced off of and when.

So you can get to the state of the machine a millisecond ago. Then you can use that to go back a millisecond from there. There is no creeping uncertainty in this process since we're using theoretical knowledge rather than physical measurements with error bars. So the information is still there in theory, but it's very much in theory.

Happily, the classical physics of little balls clacking around into each other is dead, so we can stop torturing ourselves over it.

[betty boop]

...quasiparticles are ephemeral energy excitations that come and go inside solid materials, somewhat like the crests of waves in an ocean do. Quasiparticles can collide and exchange velocity as billiard balls do and otherwise behave fleetingly like standard particles, he notes.

Fascinating, Doc. I'm bookmarking the article for further study. Thanks so very much for the link!

[betty boop]

Snoke says that the magnon-making study, while promising, lacks firm evidence that the magnetic waves exactly match each other as they should in a condensate.

Why should they be expected to exactly match? Shouldn't some allowance be made for Planck's constant?

Just wondering, Doc. Your thoughts?