Positronium (Ps) is an unstable exotic atom bound state consisting of an electron and its anti-particle, a positron. The orbit and energy levels of the two constituent leptons are analogous to, but significantly different than those of the hydrogen atom. May also use for similar systems such as muonium.
Questions tagged [positronium]
31 questions
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votes
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Does positronium have a stable crystalline phase?
I wonder if there is a way to stabilize and store positronium in a way that the mass of storage device is negligible to the antimatter fuel
It is known that excited Ps atoms with high n (rydberg or rydberg-like) have estimated lifetimes of the order…
lurscher
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12
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4 answers
What kind of matter is positronium?
What kind of matter is positronium? Normal matter, antimatter, exotic matter or something else?
We know:
Matter is made up of electrons, protons and neutrons.
Antimatter is made up of positrons, antiprotons and antineutrons.
But positronium is…
10
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3 answers
Why does positronium decay into 2 photons more often than into 3 photons?
I cannot find the answer to the above question.
I know that para-positronium is created with a probability of $25\%$ and decays into 2 photons, while ortho-positronium is created with a probability of $75\%$ and decays into 3 photons.
I also know…
Johanna Anna
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How did Ernest Sternglass’ phenomenologically incorrect model of the neutral pion predict its mass and lifetime so accurately?
In 1961, Ernest Sternglass published a paper where, using what seems to be to be a combination of relativistic kinematics and Bohr’s old quantisation procedure, he looked at the energy levels of a set of metastable electron-positron states, and…
tomdodd4598
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Size of positronium
Positronium consists of an electron and a positron. By what factor is a positronium atom bigger than a hydrogen atom?
The solution has been explained to me. The characteristic length when solving for the energy levels of the hydrogenic atom is the…
Tarrare
- 73
5
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How to treat semi-relativistic bound states?
I’m interested in semi-relativistic bound state, positronium, bottomonium, charmonium, etc.
One way to treat such bound states in relativistic QFT is Bethe-Salpeter equation:
$$(\Box+m^2)(\Box +m^2) \chi_{P}(x_{1},x_{2})+\int d^4z_1 d^4z_2…
Siam
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2 answers
Positronium energy level in QED
I'd like to know if it is possible to compute positronium mass and lifetime from a QED approach.
I'm searching for some literature on how to treat resonances in QED (or general QFT) ; most of the articles I've found are about corrections to these…
Mirajane
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4
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Why do the electron and positron creation operators anti-commute?
I am learning QFT and is baffled by a minor problem.
The electron and the positron should be distinguishable, as they have different charges. So why do their creation operators anti-commute? They should commute with each other, just like the…
S. Kohn
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Why is the speed of light in vacuum frequency-independent?
I recently came across this paper: Mainland & Mulligan, Foundations of Physics 50(5), 457–480, "Polarization of Vacuum Fluctuations: Source of the Vacuum Permittivity and Speed of Light" (2020). They calculate the speed of light in vacuum in the…
A. P.
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4
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materials that repel positrons?
In this article is discussed at some length positron formation in metallic surfaces.
Positrons have work functions that describe how much energy they have to receive in order to be extracted from the surface (just like the photoelectric effects…
user56771
- 873
4
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positronium BEC stability
After reading this article regarding Positronium BEC formation (for lasing purposes), there is a mention in there regarding Ps "up" atoms not annihilating with "down" atoms, the article is pretty vague about it and does not give much details, but i…
lurscher
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3
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Why positronium can annihilate in vacuum?
I thought that the annihilation process of positronium cannot take place without a third-party particle. This can be directly derived from energy & momentum conservation:
energy conservation: $$h\omega=E_e+E_p+E_{third}$$
momentum conservation:…
Janek_Kozicki
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Would cooling matter and antimatter to as close to Absolute Zero as possible allow them to coexist?
I was reading about Bose-Einstein condensates and how they affect matter and energy, and I wondered if "draining" that amount of energy from an atom of hydrogen and positronium would potentially allow you to form H2 gas out of the two types of…
mcchucklezz
- 778
3
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2 answers
Stability of the hydrogen atom and positronium
I am trying to get a better understanding of why positronium decays while a hydrigen atom is stable. In the case of positronium, I can write an elementary process were the leptons annihilate into two photons. But for the case of an hydrogen atom, I…
Whelp
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How would a cloud of ortho-positronium atoms behave near a magnetic dipole?
The force on a macroscopic magnetic dipole with dipole moment $\mathbf{m}$ in an inhomogeneous magnetic field $\mathbf{B}(\mathbf{r})$ is given by
$$\mathbf{F} =\nabla (\mathbf{m} \cdot \mathbf{B}(\mathbf{r})).$$
If there was a cloud of…
uhoh
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