Basic questions about E=mc^2 energy conversion

[Tldrknhndsm]

In nature how and where is energy converted to matter, where do the necessary conditions exist, is the process well understood, pure theory, or not understood at all?

 

[PeroK]

The relativistic energy-momentum equations, of which $E= mc^2$ is a special case, form the basis of all high energy particle collisions and dynamics. This includes particle scattering, creation and decay.

Most of the particles in the standard model are short lived and quickly decay into smaller particles, with the reduction in rest mass being released as kinetic energy.

 

[Hill]

(https://en.wikipedia.org/wiki/Pair_production)

 

[Dale]

In nature how and where is energy converted to matter

There is no such thing as free floating energy just flitting around the universe waiting to get converted to matter. Energy is always associated with the state of some field. One field with a certain amount of energy can be changed into another field or fields with the same amount of energy.

 

[Vanadium 50]

To take it a step further, if you think of energy as some kind of "stuff", you will draw all sorts of incorrect conclusions. Best to move off that position as soon as possible.

 

[haushofer]

In nature how and where is energy converted to matter, where do the necessary conditions exist, is the process well understood, pure theory, or not understood at all?

It depends on what you mean by "understanding something well".

 

[Herman Trivilino]

In nature how and where is energy converted to matter, where do the necessary conditions exist, is the process well understood, pure theory, or not understood at all?

In the equation $E_o=mc^2$ the $m$ stands for mass, not matter. It is one of the consequences of the Einstein mass-energy equivalence that mass is not a measure of the quantity of matter.

Edit: The concept is well-understood in both theory and practice. It has been confirmed in a great variety of situations and is now accepted as fact. Note that of course that wasn't always the case, it took years or perhaps even decades for the concept to gain overwhelming acceptance.

 

[pervect]

In nature how and where is energy converted to matter, where do the necessary conditions exist, is the process well understood, pure theory, or not understood at all?

I would say that energy is converted to matter in particle creation, just as matter is converted to energy in particle anti-particle annihiliation.

I don't know all the necessary conditions offhand - there are various quantities that are conserved in the process, some fundamental ones like energy and momentum, some exotic things - "flavour" conservation comes to mind, but I'm not sure my understanding of it as a literally conserved quantity is really accurate. You might repost to the particle physics forum if you need a better answer.

I would say the process is well understood , the current understanding is embodied in what we call the "standard model of particle physics". Experiments are of course being done to test the model, but the model is well understood, quite accurate, and widely accepted.

On a related note, relativity talks about the relationship between energy and mass (and also momentum). This isn't quite what you asked about, your question as interpreted literally is about particle physics as you asked about conversion from energy to matter. But it's possible that your intention was to ask about the relation between energy and mass instead. Several posters have already talked about this, if that was closer to your original question. I would add that if this was your question, it's best to add momentum into the question, as it's related, as I implied earlier.

 

[PeterDonis]

I would say that energy is converted to matter in particle creation, just as matter is converted to energy in particle anti-particle annihiliation.

For suitable definitions of "energy" and "matter", basically that "energy" means "massless fields" and "matter" means "fields with rest mass", this is true.

The problem is that that definition of "energy", at least, doesn't really correspond to anything you will find in the actual physics literature. What you find in the actual physics literature corresponds to what @Dale said in post #4.

 

[Sagittarius A-Star]

I would say that energy is converted to matter in particle creation, just as matter is converted to energy in particle anti-particle annihiliation.

I think here the word "matter" could be replaced by "rest-energy, that is needed for the interaction with the Higgs-field".

 

[PeterDonis]

I think here the word "matter" could be replaced by "rest-energy, that is needed for the interaction with the Higgs-field".

Rest energy isn't "needed for the interaction" with the Higgs field, it is produced by the interaction with the Higgs field.

Also, if you call it "rest energy", that's energy, and you're no longer talking about "converting energy to matter", since you're saying matter is energy, not something different.

 

[Sagittarius A-Star]

Rest energy isn't "needed for the interaction" with the Higgs field, it is produced by the interaction with the Higgs field.

In a particle creation, no energy is produced or lost in the system.

Also, if you call it "rest energy", that's energy, and you're no longer talking about "converting energy to matter"

Yes, I say that energy can be only converted to energy.

 

[PeterDonis]

In a particle creation, no energy is produced or lost in the system.

True, but that doesn't contradict what i said or support your claim about the Higgs field. The Higgs interaction produces rest energy, but not from nowhere; it produces it from energy that, before the electroweak phase transition and the start of the Higgs interaction that gives certain fields rest mass, was stored in massless fields. (And, btw, that Higgs interaction is not "particle creation".)

Yes, I say that energy can be only converted to energy.

That is one way of looking at it, but not the only way.