Thursday, June 11, 2020

BEC In Space

 Not as amusing as Pigs In Space, but still quite impressive.

The ISS is useful after all! :) Physicists have created the first controlled Bose-Einstein condensate in low earth orbit, thus eliminating the issue of gravitational effects[1] that affects the stability of the condensate.

A review of the work can be found here.

As discussed, Bose–Einstein condensation requires low temperatures, at which atoms hardly move. However, when a BEC is released from a magnetic trap so that experiments can be carried out, repulsive interactions between the atoms cause the cloud to expand. Within a few seconds, the BEC becomes too dilute to be detected. The expansion rate can be reduced by decreasing the depth of the trap, and, thereby, the density of atoms in the trap.

On Earth, the planet’s gravitational pull restricts the shape of possible magnetic traps in such a way that a deep trap is needed to confine a BEC (Fig. 1a,b). By contrast, Aveline and colleagues found that the extremely weak gravity (microgravity) on the International Space Station allowed rubidium BECs to be created using shallow traps. As a result, the authors could study the BECs after about one second of expansion, without needing to manipulate the atoms further.

But this is more than just an achievement on the scientific level. It is also a technological feat because of the numerous requirements that are needed to be able to have an experiment on the ISS, as stated in the review:

Aveline and colleagues’ technological achievement is remarkable. Their apparatus needed to satisfy the strict mass, volume and power-consumption requirements of the International Space Station, and be robust enough to operate for years without needing to be serviced. The authors’ Earth-orbiting BECs provide new opportunities for research on quantum gases, as well as for atom interferometry, and pave the way for missions that are even more ambitious.

If you have ever designed an experiment, you know of all the issues involved, not just the scientific ones. This includes engineering, robustness, economics/costs, etc. So I can't imagine what they had to come up with to be able to send something up there and basically run this with very little to no involvement from the astronauts onboard.

Very well done indeed!


[1] D.C. Aveline et al. Nature v.582, p.193 (2020).

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