What is Quintessence and its role in understanding dark energy?

[fanieh]

In Beyond the Standard Model they propose so many extra things like..

* Branes
* Superpartners
* KK particles
* Extra Dimension
* Strings
* TeV scale black hole
* WiMPs
* Warped Dimensions
* Monopoles

Most or all of the above hasn't even been detected. Did you notice most of the above are either new particles or dimensions. Do they also propose new kinds of fields (or stuff).. for example.. in addition to scalar and vectorial fields. Could there be fields (or maybe it's called by another name like holographic surface or scalar or something) that can store information.. like you can program it to hold certain data? Any physicists into it? Is it impossible? Why impossible?

 

[Urs Schreiber]

most of the above are either new particles or ...

That's essentially the definition of a "BSM = beyond the standard model". Either new particles (if its still a model in local gauge field theory, just not the standard model anymore) or something entirely new (if it's a model in a theory different from local gauge field theory).

With 95.1% of the total energy density and 84.5% of the the total mass density of the observable universe presently unknown (dark), it seems more probable than not that beyond the standard model a lot of new stuff is waiting to be discovered.

 

[fanieh]

That's essentially the definition of a "BSM = beyond the standard model". Either new particles (if its still a model in local gauge field theory, just not the standard model anymore) or something entirely new (if it's a model in a theory different from local gauge field theory).

With 95.1% of the total energy density and 84.5% of the the total mass density of the observable universe presently unknown (dark), it seems more probable than not that beyond the standard model a lot of new stuff is waiting to be discovered.

What is the best word to describe fields that can have information contents? or should the word "field" be reserved only for the "fields" in quantum field theory? If so.. what term do you suggest for this something that can hold information contents?

 

[Urs Schreiber]

What is the best word to describe fields that can have information contents?

Every field has information content. The text information that you and me are exchanging hereby is all encoded in the electromagnetic field.

 

[fanieh]

Every field has information content. The text information that you and me are exchanging hereby is all encoded in the electromagnetic field.

I mean fields that can hold information contents coming from the mind. There are so many dozens experiments about this in the underground with non-null results. These are all rejected by most physicists because they reasoned its not part of the standard model. But like you said "95.1% of the total energy density and 84.5% of the the total mass density of the observable universe presently unknown". The forum moderators rule is only sharing those from the mainstream. But the mainstream only has limited data picked by by limited consensus. Anyway. I won't share the links because they will be deleted by the mentors immediately. So i'll only ask theoretical thing. What should you call this field that can hold other information contents that is not electromagnetic, weak, strong or gravitational? If it were to exist that is outside of local gauge field theory. What should it be called? That's all (moderators).

 

[member 11137]

I mean fields that can hold information contents coming from the mind. There are so many dozens experiments about this in the underground with non-null results. These are all rejected by most physicists because they reasoned its not part of the standard model. But like you said "95.1% of the total energy density and 84.5% of the the total mass density of the observable universe presently unknown". The forum moderators rule is only sharing those from the mainstream. But the mainstream only has limited data picked by by limited consensus. Anyway. I won't share the links because they will be deleted by the mentors immediately. So i'll only ask theoretical thing. What should you call this field that can hold other information contents that is not electromagnetic, weak, strong or gravitational? If it were to exist that is outside of local gauge field theory. What should it be called? That's all (moderators).

• Concerning dark matter (DM) and dark energy (DE), the scientific teams are testing the foundations and verifying the experimental data to be sure that what has been detected is really new and behind the standard model (BSM).
• I am not an expert but what I can tell you is that if you take the time to read, and not only to ask (with respect for you), you certainly will discover a lot of scientific works made by very serious professional people, even behind the standard model (BSM) or, more exactly, starting from the BSM and looking for plausible mechanisms allowing the incorporation of new phenomenon, e.g.: dark matter (DM).
• In general, you will not find science-fiction scenario and, in general too, people are going slowly and carefully from what is known (SM) to what is unknown (for example: DM). This tactic doesn’t only apply in physics but everywhere all along the life when you have to put your feet in an unknown sector. Professionals have a reputation to maintain. Concretely, if you are looking or waiting for a fantastic scoop, you will be disappointed.
• The theories are developed quite quicker than the observations can be realized and analyzed.

 

[ohwilleke]

That's essentially the definition of a "BSM = beyond the standard model". Either new particles (if its still a model in local gauge field theory, just not the standard model anymore) or something entirely new (if it's a model in a theory different from local gauge field theory).

With 95.1% of the total energy density and 84.5% of the the total mass density of the observable universe presently unknown (dark), it seems more probable than not that beyond the standard model a lot of new stuff is waiting to be discovered.

I really dislike that framing of the situation because while "dark matter" is indeed unknown, "dark energy" is explained very well to the limits of experimental accuracy with the simple addition of the cosmological constant to the equations of general relativity which isn't mysterious, unknown, or not understood at all. The cosmological constant is the lambda in the lambdaCDM standard model of cosmology. It is just a simple tweak to an equation put there in the first place by its original creator. In that formulation, it isn't dark beyond the Standard Model stuff, it is simply a property of space-time itself.

When the unexplained energy density of the universe is quoted as more like 25% and the explained part is something on the order of 75% somebody has a much more meaningful understanding of how much of the universe we understand.

Certainly dark matter requires some sort of BSM physics. But, dark energy does not.

Also, even if we someday learn that the cosmological constant is not the right answer and that BSM physics explains it better, it is at a minimum, a very good approximation of the right answer, so we still understand reality to a very good approximation. Even if the the cosmological constant is wrong, at a minimum it is like doing solar system physics with Newtonian gravity rather than GR - not exactly right but damn close for the vast majority of applications.

 

[Urs Schreiber]

I really dislike that framing of the situation because while "dark matter" is indeed unknown, "dark energy" is explained very well to the limits of experimental accuracy with the simple addition of the cosmological

Sure, but beyond the fact that it's easy to fit the parameter, there is a huge mystery behind the cosmological constant, signified by its size compared to its natural value, and in view of the fact that inflation needs it to become a dynamical field, which itself has no reason not to be just an effective field made up of more fundamental fields. In cosmological models, due to their large scape accuracy only, a vast amount of fine detail (known and unknown) is absorbed into innocent looking parameters.

 

[ohwilleke]

signified by its size compared to its natural value

Until physicists wake up and recognize that there is no such thing as a "natural value" the discipline is doomed.

 

[Urs Schreiber]

Until physicists wake up and recognize that there is no such thing as a "natural value" the discipline is doomed.

It would be easy for me to give a similarly snarky reply. But it would lead us nowhere. What I am pointing out is not something that is sensibly brushed away:

There is no reason to expect that the "constants" that enter cosmological models are not placeholders for complex effects. There is no reason to expect that the cosmological constant is really just a number plugged into the order-0 term in the Einstein-Hilbert action. In fact the very same standard model of cosmology prefers cosmic inflation, where the "cosmological constant" is explicitly modeled as a scalar field. And then there is no reason to expect that this scalar field, in turn, is not itself an effective placeholder for more complex phenomena that it serves to parameterize.

 

[lpetrich]

The cosmological-constant term can be interpreted as the energy-momentum tensor of a kind of matter with (pressure) = - (mass density)*c².

In fact, there are some theories that say that this term is produced by some elementary-particle field that can vary in space and time. This field has even been given a name: quintessence. [1304.1961] Quintessence: A Review, A quintessential introduction to dark energy - steinhardt.pdf

Quintessence or "fifth stuff" is an old name for the material of the celestial regions. In this accounting, the first four elements are the traditional ones: earth, water, air, and fire.