Math Blog. Nerd.

[houglet]

I've finally put up a non-trivial post at my new math blog. It's about the research I've been doing this summer. Not the most accessible thing I've ever written but I swear I'll put up way more readable things in the (near-ish) future.

Comments

[cupacoffey]

What is an optical random potential and why do the Bose-Einstein condensates have to be in a potential to be "trapped" or whatever?

P.S. Hallelujah to stationary states of the simple harmonic oscillator.

the SHO is my BFF

[houglet]

An optical random potential is basically a laser shot through a diffuse piece of glass to create different intensities. The BEC interacts with it like it would with any alternating magnetic field.

The trapping potential... Well... So...
To make a glob of alkali metal gas (these are particularly suceptible to the evaporative cooling described below) get cold enough without liquifying first they trap the gas with lasers and make al the atoms slow down and stay in a little blob. This is the laser cooling part. This is cold enough to form a BEC so they then do evaporative cooling.
They turn of a magnetic field and keep all of the atoms with say... spin down. Then they quickly alternate the direction of the magnetic (trapping) field at a frequency that corresponds to the energy of the atoms they want to kick out. This causes the atoms of that energy to change the direction of their spins and fly out of the trap.

So the trap is needed to make it cold enough for a BEC to form.

[qiezi]

You might want to try the wavepacket approach to your BEC problem. Here's a new textbook whose whole "premise" is exactly this approach.

http://www.amazon.com/Introduction-Quantum-Mechanics-Time-Dependent-Perspective/dp/1891389238