Congratulations to Dominik Schneble and the rest of his group in the basement at Stony Brook. After two and a half years of trying, with one laser problem after another, Dominik’s group (with whom my research is very closely affiliated) have finally succeeded in creating the first Bose-Einstein condensate at Stony Brook. At 5:55 AM Saturday, after a solid week of 24 hour shifts attempting to make the condensate after their laser was finally released from customs, the group observed the characteristic absorption pattern indicative of a BEC in flight. This was done just in time, too. Daniel Pertot, a German exchange student, had left the lab at around 8 AM, noting in the log that “this is not working. I’m going home.” Just ten minutes later, a large note simply said “BEC?!”. At this point, Daniel was called and returned to witness the condensate before he returned to Germany, ending his tenure at Stony Brook with research worthy of a masters thesis.

For those of you not in the know, a Bose-Einstein condensate is what happens when you take a cloud of cold atoms, and cool them down below a certain critical temperature. At this critical temperature, the system “condenses” so that a macroscopic percentage of the atoms occupy the ground state of the trap. In some sense, the atoms all become a “super atom” occupying the same state.

The theory surrounding Bose-Einstein condensation originated with the work of Satyendra Nath Bose, an Indian physicist whose work would lead to many other people receiving the Nobel Prize in Physics. Bose’s work was expanded upon by Einstein, who noted that the same statistics which Bose had worked out for light could also be applied to some atoms. Einstein postulated the actual existence of the condensate based upon Bose’s work around 1924. However, it was not until achieved experimentally until 1995, when Eric Cornell and Carl Wiemann at the University of Colorado at Boulder created a BEC using rubidium atoms cooled to 170 nanoKelvin.

The great experimental difficulty surrounding Bose-Einstein condensates revolves around their remarkably low critical temperatures. The methods of laser cooling and trapping that are currently used are based around the notion that the frequency of light shifts with a moving atom, so that atoms moving relative to light experience a greater impulse, causing them to slow down, creating a so-called “optical molasses”. Bill Phillips and other physicists (Stony Brook’s Hal Metcalf was another early contributer) developed these methods, as well as methods of using magnets to couple with the magnetic moements of the atoms, confining them to a central location to help achieve the critical density. The critical temperatures for most of these gases is in the hundreds of nanoKelvin range — for purposes of comparison, liquid helium-4 condenses at around 5.2 Kelvin, a full 10000000 times hotter. Thus, the methods of “evaporative cooling”, the optical molasses, and other tools had to be developed.

The interest in BECs is their peculiar behavior. They behave as massive single particles, but because they have internal interactions various nonlinear effects arise that are not observed in typical single-body systems. Included among these are quantized vortices that are typically observed in superfluids. There is also a great deal of interest in BECs because their self-interactions can be controlled to some extent, allowing AMO experimental physicists to produce BEC replicas of the Hubbard model, Mott insulators, and other phenomena of solid state physics in an incredibly pure and controllable state. This, of course, is where my research interest comes in.

So congratulations again, Dominik & Co.!