Form of energy at time of big bang

[Twodogs]

Physics describes energy in various forms and each with an appropriate unit of measure. I am curious as to what can be said about the 'form' of energy in the universe's first seconds.
Online references locate the Big Bang singularity at an estimated 13.787±0.020 billion years ago with the temperature of the universe immediately after the Big Bang estimated to be around 10 billion degrees Celsius (18 billion degrees Fahrenheit)

And there is this...
Electroweak Epoch, from $10^{-36}$ seconds to $10^{–12}$ seconds:
As the strong nuclear force separates from the other two, particle interactions create large numbers of exotic particles, including W and Z bosons and Higgs bosons (the Higgs field slows particles down and confers mass on them, allowing a universe made entirely out of radiation to support things that have mass).

Perhaps is difficult and not exacting to describe energy with terms like temperature or radiation in this exceedingly brief period of the early universe, but Question: What was the form of energy in the first micro seconds, or is it somewhat nondescript?

Thanks for thoughts on this

 

[jedishrfu]

The Big Bang starts as a nondescript singularity where all matter is compressed to a single point and the four primary forces are merged into a single force.

Moments into the expansion quarks appear then subatomic particles while the forces separate into the ones we understand today.

Since we base our notions of energy around the four forces it's meaningless to say in which form the energy resides at the moment of singularity.

There is a book by Weinberg: The First Three Minutes that details to moments following the Big Bang when spacetime is created.


@PeterDonis can explain it better.

 

[PeterDonis]

The Big Bang starts as a nondescript singularity where all matter is compressed to a single point

Not really, no. The "singularity" itself is not part of spacetime, and viewing it as "all matter compressed to a single point" is not very useful. And the proper referent of the term "Big Bang" is something else; see below.

the four primary forces are merged into a single force.

This has to do with the temperature being high enough, and doesn't really depend on whether or not there is an initial singularity, or even on being in the early universe. Note that not all models have an initial singularity; for example, in "eternal inflation" models there is none.

The reason I point these things out will be clear below.

I am curious as to what can be said about the 'form' of energy in the universe's first seconds.

The "Big Bang", when that term is properly used, actually does not refer to an "initial singularity" (since, as I noted above, not all models even have one). It refers to the hot, dense, rapidly expanding state that is the earliest state for which we have reasonably good evidence. So your question really is two questions: first, what was that state in terms of particle, or more properly quantum field, content? And second, what came before it?

The first question is easy to answer: the hot, dense, rapidly expanding "Big Bang" state had all of the quantum fields in the Standard Model (quarks, leptons, and gauge bosons) in very high temperature states, meaning all of them contained a very large energy density. Note that these were the pre-electroweak phase transition fields, so they were all massless, the boson fields (gauge and Higgs) were somewhat differently arranged from how they are today, and "high temperature" just means "a temperature well above the electroweak phase transition temperature".

As the universe expanded and cooled from this point, the electroweak phase transition happened once the temperature decreased to an appropriate point. That did two things: it "rearranged" the electroweak and Higgs bosons somewhat, and it gave some of the boson fields (the W+, W-, and Z, and also the Higgs, although that gets into some complications that I don't want to dig into here) and all of the fermion fields (quarks and leptons) mass. That changed how energy got distributed between the fields as the universe cooled further.

The second question, what came before the hot, dense, rapidly expanding "Big Bang" state, depends, at a high level, on whether you adopt an inflation model or not. In inflation models, that "Big Bang" state is produced at the end of inflation. Prior to that, during inflation, all of the Standard Model fields are in their vacuum states, and the inflaton field is in a "false vacuum" state with a huge energy density, and since that field's energy density acts like a cosmological constant, there is rapid exponential expansion during inflation. But at some point the inflaton field transitions from that "false vacuum" state to its true vacuum state, and all that huge energy density gets transferred to the Standard Model fields; that is what produces the "Big Bang" state.

If you don't adopt an inflation model, I'm not sure what other options there are for explaining where the "Big Bang" state came from. Mathematically speaking, one could just assert that that was the state right after an "initial singularity", but physically, I don't know that anyone is really satisfied with that kind of model.

 

[Twodogs]

Thanks for walking through that. I imagine it took huge effort of a lot of folks to model what occurred in the first moments of the universe. There is a website entitled, Big Bang Timeline (google search) that breaks down the first micro seconds, field and particle formation. For example the "Quark Epoch - from 10^-12 to 10^-6 seconds wherein, "Quarks, electrons and neutrinos form in large numbers as the universe cools off to below 10 quadrillion degrees, and the four fundamental forces assume their present forms. Quarks and antiquarks annihilate each other upon contact, but, in a process known as baryogenesis, a surplus of quarks (about one for every billion pairs) survives, which will ultimately combine to form matter."

I don't know if that is current information, but there and in your description one gets a strange and inexplicable impression of all this energy being "poured" into a preexisting molds of field and particle forms; like the universe knew how it was going to sort itself out into enduring forms i.e., protons with a half-life of 1.67 x 10^34 years. Are physicists at all curious as to the why of this. Thanks. (And can't deal with LaTex at the moment)

 

[PeterDonis]

all this energy being "poured" into a preexisting molds of field and particle forms

Sort of. The Standard Model, which is what the things I said and the things you read are based on, is not believed to be a fundamental theory--that is, its "menu" of quantum fields is not believed to be the "lowest level" of fields, or whatever, that exists. One of the things about quantum field theory that is not emphasized very much is that you can build quantum field theories on top of other quantum field theories, in multiple levels--or, to put it another way, at different energy scales very different "menus" of quantum fields can turn out to be the best descriptions of what is going on. The Standard Model itself has two "menus" of fields--the one before electroweak symmetry breaking and the one after. So it's hard to say that any particular "menu" of fields is "preexisting".

Are physicists at all curious as to the why of this.

Yes; it's a major motivation for searches for a "theory of everything", which is supposed to be the most fundamental level that all the other stuff is built on. But no such theory has yet been found. String theorists like to say that string theory is it, but there is no evidence that it is.

 

[Twodogs]

Thank you.
The purpose of my initial question was to understand whether 'energy' must always manifest in a particular 'form' in the observable physical universe. That is, can energy exist/manifest in some form-free state or, rather, is form a necessary, concomitant part if energy?

Looking at the timeline of the first second it would seem that, if energy exists in a form-free state, it did so for an exceedingly brief fraction of a second.

And being reminded of how this cosmological drama played out, it is very curious that the first steps of formation seem to have been guided by a fixed menu of possible field and particle forms. That does suggest that the physical universe is emergent and informed by a more fundamental substrate. Of course, we only have our universe to look at. Perhaps, after all, dice are involved.

 

[DaveC426913]

Thank you.
The purpose of my initial question was to understand whether 'energy' must always manifest in a particular 'form' in the observable physical universe. That is, can energy exist/manifest in some form-free state or, rather, is form a necessary, concomitant part if energy?

The best description I have heard for energy is that it is not a thing; it is an accounting system for some traits that things have. Objects can can have vibrational energy, kinetic energy and potential energy, heat energy etc. and you can convert one form to another. A bouncing ball is just one example of a system that converts between forms of energy.

 

[PeterDonis]

The purpose of my initial question was to understand whether 'energy' must always manifest in a particular 'form' in the observable physical universe.

This is much too vague to even be answerable.

A better question would be, what is "energy" to begin with? @DaveC426913 in post #7 gave a good heuristic answer to that. To add to that answer, "energy" is always associated with some kind of physical system. In the early universe models you have been asking about, it is associated with quantum fields. More technically, "energy" is an observable in QM: it's a property of quantum systems that you can measure.

the first steps of formation seem to have been guided by a fixed menu of possible field and particle forms

No, the "menu" was not "fixed". See my post #5.

 

[gmax137]

The best description I have heard for energy is that it is not a thing; it is an accounting system for some traits that things have.

I'm certainly not qualified to chime in here on an "A" level thread, but that's how I see it.

What convinced me of this notion is the realization that kinetic energy is frame dependent. The v in the v^2 term depends on your choice of reference. If someone has a more sophisticated take, I'd like to hear it.

 

[Twodogs]

Sort of. The Standard Model, which is what the things I said and the things you read are based on, is not believed to be a fundamental theory--that is, its "menu" of quantum fields is not believed to be the "lowest level" of fields, or whatever, that exists. One of the things about quantum field theory that is not emphasized very much is that you can build quantum field theories on top of other quantum field theories, in multiple levels--or, to put it another way, at different energy scales very different "menus" of quantum fields can turn out to be the best descriptions of what is going on. The Standard Model itself has two "menus" of fields--the one before electroweak symmetry breaking and the one after. So it's hard to say that any particular "menu" of fields is "preexisting".

Building quantum field theories on top of other quantum field theories is a new notion.
But, the intense energy and pressure in the early universe would not have had guidance from whatever our field theories propose in sorting itself into fields and then particles and antiparticles. I guess we observe only the dynamical forms that endured and its is curious that they turned out to be so fruitful in the complexity of their combinations.

Yes; it's a major motivation for searches for a "theory of everything", which is supposed to be the most fundamental level that all the other stuff is built on. But no such theory has yet been found. String theorists like to say that string theory is it, but there is no evidence that it is.

This is much too vague to even be answerable.

A better question would be, what is "energy" to begin with? @DaveC426913 in post #7 gave a good heuristic answer to that. To add to that answer, "energy" is always associated with some kind of physical system. In the early universe models you have been asking about, it is associated with quantum fields. More technically, "energy" is an observable in QM: it's a property of quantum systems that you can measure.


No, the "menu" was not "fixed". See my post #5.

Well, mass/energy seems to be the fundamental stuff of nature it is curious that @DaveC426913 was reluctant co call energy a thing As I recall, it took an incredible amount of careful lab work to discover energy as a thing, quite surprising really, a need for a new name, en-ergos, a noun, a conserved property found to be that which animates the multitude of action verbsmeasured by transfer (moving piston to temp of fluid stirred by paddle

This is much too vague to even be answerable.
A better question would be, what is "energy" to begin with? @DaveC426913 in post #7 gave a good heuristic answer to that. To add to that answer, "energy" is always associated with some kind of physical system. In the early universe models you have been asking about, it is associated with quantum fields. More technically, "energy" is an observable in QM: it's a property of quantum systems that you can measure.


No, the "menu" was not "fixed". See my post #5.

This is much too vague to even be answerable.

A better question would be, what is "energy" to begin with? @DaveC426913 in post #7 gave a good heuristic answer to that. To add to that answer, "energy" is always associated with some kind of physical system. In the early universe models you have been asking about, it is associated with quantum fields. More technically, "energy" is an observable in QM: it's a property of quantum systems that you can measure.


No, the "menu" was not "fixed". See my post #5.

 

[PeterDonis]

Building quantum field theories on top of other quantum field theories is a new notion.

No, it isn't. It's been done for decades.

the intense energy and pressure in the early universe would not have had guidance from whatever our field theories propose in sorting itself into fields and then particles and antiparticles.

I don't know where you're getting this from. Please bear in mind that personal speculation is off limits here.

mass/energy seems to be the fundamental stuff of nature

I don't know where you're getting this from either.

 

[PeterDonis]

The original question has been addressed as well as it can be, and the thread is degenerating into speculation. Thread closed.