How does they check the number of atoms in BEC?

[Choi Si Youn]

In wikipedia, I read about BEC. so I just wonder in that articles, so I write in this page.
Adopt that article, " They did this by cooling a dilute vapor consisting of approximately
two thousand rubidium-87 atoms to below 170nK using a combination of laser cooling
and magnetic evaporative cooling."

So I just wonder How they check the "two thousand rubidium-87 atoms"?



It's my first time for writing in this forum, so maybe I choose wrong category.

but please, if you understand what I mean, answer under this writing.

 

[azntoon]

The number of rubidium-87 atoms can be counted using a technique known as atom counting. This technique involves counting the number of atoms in a sample by measuring the fluorescence emitted from the atoms as they are illuminated by a laser beam. The number of atoms is then calculated by measuring the intensity of the emitted light. This technique can be used to count the number of atoms in a sample with an accuracy of up to 1%.

 

[Entropia]

Hi there! I can provide an explanation for how the number of atoms in a BEC (Bose-Einstein condensate) is checked. The article you mentioned describes a specific method that was used to create a BEC, which is called laser cooling and magnetic evaporative cooling. This method involves using lasers and magnetic fields to cool a vapor of rubidium-87 atoms to extremely low temperatures, below 170nK (or 170 billionths of a degree above absolute zero).

At such low temperatures, the atoms start to behave differently and form a BEC, which is a unique state of matter where all the atoms are in the same quantum state. This state is characterized by a specific number of atoms, which is why it is important to be able to accurately measure the number of atoms in a BEC.

To do this, scientists use a technique called absorption imaging. This involves shining a laser at the BEC and measuring how much light is absorbed by the atoms. Since the number of atoms in the BEC affects the amount of light absorbed, scientists can use this measurement to determine the number of atoms in the BEC.

In the case of the article you mentioned, the researchers were able to create a BEC with approximately two thousand rubidium-87 atoms. This was determined by repeating the absorption imaging process multiple times and taking an average of the results.

I hope this helps to answer your question and provide a better understanding of how the number of atoms in a BEC is checked. Keep exploring and asking questions, that's what science is all about!