For the first time, Northwestern University physicists have coaxed a single positron — the antimatter counterpart of an electron — into an exquisitely controlled quantum state.
How did they know at any given point that it was still there? Wouldn’t they have to interact with it to be sure, causing an explosion and annihilating it? The explosion would be incredibly small with just one particle. Is the lack of explosion their only evidence that they had contained it? I’m stumped as to what it actually means to have one particle like this. How can you even know what temperature it is without interacting with it? And how do you interact with it without destroying it?
The particle does not have to interact directly with matter to be observable.
Apparently they built what they called a “one-positron quantum cyclotron”, meaning they made their single positron “fly in a circle” with magnetic fields to trap it.
That way you have a moving charge, which you can manipulate with electromagnetic radiation, microwaves in this case, the same way as you could with normal matter. That also means you can make your particle emit electromegnetic radiation that will tell you it is still there without touching anything.
Still kind of mindblowing, that they can reliably detect anything coming from a single positron though.
How did they know at any given point that it was still there? Wouldn’t they have to interact with it to be sure, causing an explosion and annihilating it? The explosion would be incredibly small with just one particle. Is the lack of explosion their only evidence that they had contained it? I’m stumped as to what it actually means to have one particle like this. How can you even know what temperature it is without interacting with it? And how do you interact with it without destroying it?
The particle does not have to interact directly with matter to be observable.
Apparently they built what they called a “one-positron quantum cyclotron”, meaning they made their single positron “fly in a circle” with magnetic fields to trap it.
That way you have a moving charge, which you can manipulate with electromagnetic radiation, microwaves in this case, the same way as you could with normal matter. That also means you can make your particle emit electromegnetic radiation that will tell you it is still there without touching anything.
Still kind of mindblowing, that they can reliably detect anything coming from a single positron though.