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Q & A: Positronium

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Most recent answer: 01/25/2015
Q:
Hello! I have these two ideas but I don't know if they are possible or not. The first one: What will happen if we attach an electron to a positron and then attach another electron to them and then another positron and it continues until it appears in a shape that we can see it with our unaided eyes? Wouldn't it be an unbreakable material? Is that theoretically possible? The second one: What will happen if we make an atom that in its nucleus we used my first idea instead of protons and neutrons and instead of electrons in electron shells we used protons? (one of my physics teacher told me that 1837 electrons equals 1 proton… so we use 1837 electrons and positrons electron for each proton and neutron in the nucleus) Is it possible?
- Sepehr Azaran (age 17)
Ahwaz.Khouzestan.Iran
A:

It depends what you mean by to attach. As you know, positron and electron are antiparticles of each other. So, if they coincide in space, they will sometimes undergo a reaction called annihilation to give two photons. However, you still can replace the proton in the atom with a positron to form an exotic atom called positronium. This is similar to a hydrogen atom in many ways because there is an equal amount of electrostatic attraction, but surely with different energy levels. So it is possible, however, this is quite unstable.

Electron orbitals need to be of negative energy (bound state in quantum jargon). You therefore obviously want the nucleus to have a negative net charge, so that it will attract the protons around. But this is also not the case, if you put equal numbers of positrons and electrons there, since they have equal but opposite charges. And you cannot use electrons exclusively, because then the nucleus would be unstable. Having a single extra electron could have worked, but by using thousands of such fermions, you cannot make a small nucleus that you are dreaming of, because they will not want to be in the same state and resist against it. 


(published on 01/25/2015)

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