Is dark energy even allowed in string theory?

October 8, 2018, Vienna University of Technology
The ESA mission Euclid is supposed to gain new insights into fundamental questions concerning string theory. Credit: ESA/C. Carreau and CERN/J. Ellis, CC BY-SA 3.0

A new conjecture is the cause of excitement in the string theory community. Timm Wrase of the Vienna University of Technology has now published his much-discussed results on recent new developments.

In , a paradigm shift could be imminent. In June, a team of string theorists from Harvard and Caltech published a conjecture which sounded revolutionary: string theory is said to be fundamentally incompatible with our current understanding of dark —but only with dark energy can we explain the of our current universe.

Timm Wrase of the Vienna University of Technology quickly realized something odd about this conjecture: it seemed to be incompatible with the existence of the Higgs particle. His calculations, which he carried out together with theorists from Columbia University in New York and the University of Heidelberg, have now been published in Physical Review D. At the moment, there are heated discussions about strings and dark energy all around the world. Wrase hopes that this will lead to new breakthroughs in this line of research.

The theory for everything

Much hope has been placed in string theory. It is supposed to explain how gravity is related to quantum physics and how we can understand the laws of nature, which describe the entire physical world, from the smallest particles to the largest structure of the cosmos.

Often, string theory has been accused of merely providing abstract mathematical results and making too few predictions that can actually be verified in an experiment. Now, however, the string theory community all around the world is discussing a question that is closely related to cosmic experiments measuring the expansion of the universe. In 2011, the Nobel Prize in Physics was awarded for the discovery that the universe is not only constantly growing larger, but that this expansion is actually accelerating.

This phenomenon can only be explained by assuming an additional, previously unknown dark energy. This idea originally came from Albert Einstein, who added it as a "cosmological constant" to his theory of general relativity. Einstein actually did this to construct a non-expanding universe. When Hubble discovered in 1929 that the universe was in fact expanding, Einstein described this modification of his equations as the biggest blunder of his life. But with the discovery of the accelerated expansion of the cosmos, the cosmological constant has been reintroduced as dark energy into the current standard model of cosmology.

TU Vienna Timm Wrase. Credit: Vienna University of Technology, TU Vienna
Like an apple in the fruit bowl

"For a long time, we thought that such a dark energy can be well accommodated in string theory," says Timm Wrase from the Institute for Theoretical Physics of the Vienna University of Technology. String theory assumes that there are additional, previously unknown particles that can be described as fields.

These fields have a state of minimal energy—much like an apple lying in a bowl. It will always lie at the very bottom, at the lowest point of the bowl. Everywhere else its energy would be higher, if we want to shift it, we have to exert energy. But that does not mean that the apple at the lowest point has no energy at all. We can put the bowl with the apple on the ground, or on top of the table—there the apple has more energy but it still cannot move, because it is still in a state of minimal energy in its bowl.

"In string theory there are fields which could explain dark energy in a similar way – locally, they are in a state of minimal energy, but still their energy has a value greater than zero," explains Timm Wrase. "So these fields would provide the so-called dark energy, with which we could explain the accelerated expansion of the universe."

But Cumrun Vafa from Harvard University, one of the world's most renowned string theorists, published an article on June 25, raising many eyebrows. He suggested that such "bowl-shaped" fields of positive energy are not possible in string theory.

The Higgs field—a contradiction

Timm Wrase of the Vienna University of Technology quickly realized the implications of this claim: "If that is true, the accelerated expansion of the universe, as we have imagined it so far, is not possible" he says. "The accelerated expansion would then have to be described by a field with quite different properties, like a tilted plane on which a ball rolls downhill, losing potential energy." But in that case, the amount of dark energy in the universe would change over time, and the accelerated expansion of the universe may one day come to a halt. Gravity could then pull all matter back together and assemble everything at one point, similar to the time of the Big Bang.

But Timm Wrase, who had already dealt with similar questions in his doctoral thesis, found that this idea cannot be the whole truth either. "Cumrun Vafa's conjecture, which prohibits certain types of fields, would also prohibit things that we already know to exist," he explains.

Wrase was able to show that the Higgs field also has properties that should actually be forbidden by Vafa's conjecture—and the Higgs field is considered an experimentally proven fact. For its discovery, the 2013 Nobel Prize in Physics was awarded. Wrase uploaded his results to the preprint website Arxiv, quickly sparking a lot of discussions in the string theory community. Now the work has been peer reviewed and published in the journal "Physical Review".

"This controversy is a good thing for string theory," Timm Wrase is convinced. "Suddenly, a lot of people have completely new ideas which nobody has thought about before." Wrase and his team are now investigating which fields are allowed in string theory and at which points they violate Vafa's conjecture. "Maybe that leads us to exciting new insights into the nature of —that would be a great success," says Wrase.

The hypotheses that arise will (at least in part) soon be tested experimentally. In the next few years the accelerated expansion of the will be measured more accurately than ever before.

Explore further: Centenary of cosmological constant lambda

More information: Frederik Denef et al. de Sitter swampland conjecture and the Higgs potential, Physical Review D (2018). DOI: 10.1103/PhysRevD.98.086004 , https://arxiv.org/abs/1807.06581

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35 comments

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dirk_bruere
2.3 / 5 (8) Oct 08, 2018
Or simply, String Theory is fundamentally wrong
rrwillsj
1.5 / 5 (8) Oct 08, 2018
My latest, unproven, unverified, speculative guesstimate is... The newly discovered (also unverified) "Majoron" particle that is hypothesized to be Dark Matter. Is claimed (unconfirmed) to be a product of the decay of tau & meson neutrinos.

My wildly speculative hypotheses is that the decay of the tau & meson neutrinos also releases what we call "Dark Energy".

This may explain several puzzling cosmological questions. If the tau & meson neutrinos decay into majorons, that could explain the abundance of electron neutrinos.

If the decay process began during the Glasma Stage of the Early Universe? Continuous to this day? The energy released producing majorons
continues to add energy into accelerating the expansion of the Universe.

Like adding heat to a hot air balloon.

Having mass, the tau & meson neutrinos would be attracted to the nearest most significant gravitational pull. Explaining why there are lumps of galaxies & where their " DM halos" originated.
Joe1963
1 / 5 (8) Oct 08, 2018
String theory is wrong: I posit this hypothesis that does away with both dark matter and also dark energy. I posit that at a distance of approximately 1.5 million light-years gravity becomes slightly repulsive, gradually increasing with distance to achieve a peak repulsion, and then decreasing with distance to zero.

Cosmological expansion is caused by galaxies pushing against each other; galactic rotation can be explained by the fact that each galaxy is surrounded by a "womb" of dust, gas, and other galaxies, and this "womb" pushes with repulsive gravity upon the outer stars of a galaxy to keep them in orbit at a higher speed than expected.

I give a cosmological / mathematical justification for this behavior in my Reddit article:

https://www.reddi...tter_is/

In the responses below, I explain how General Relativity can be adjusted so as to retain time dilation while rejecting curved space and retaining flat, 3D, Euclidean space.
danR
1.2 / 5 (9) Oct 08, 2018
String Theory:
1. A grand unified theory so flexible that it can be tweaked at a moment's notice to be unfalsifiable.
2. A Science cargo-cult.
3. The moral successor to Phlogiston and Aether theories.
4. A successful pathway to a physics doctorate.
5. A non-impediment to tenure.
Old_C_Code
1.3 / 5 (8) Oct 08, 2018
6. If it moves, chase it.
antialias_physorg
4.5 / 5 (13) Oct 08, 2018
This is a pretty big deal for string theory because they fially have something where they make different predictions from the standard model (i.e. one can finally start going about devising experiments to see which one holds - or at thevery least which flavours of string theory can be ruled out)

1. A grand unified theory so flexible that it can be tweaked at a moment's notice to be unfalsifiable.

The entire point of the article is that this is no longer true.
rrwillsj
2 / 5 (6) Oct 08, 2018
Joe, I just do not see how galaxies can "push" against one another. Especially as the observations of galactic formation have invariably supported the "attractant" collision scenarios.

Thinking of the stars of galaxies as particles? How could they get mixed together if the collective bodies of stars were repelling one another?

There is an old engineer's saying "You cannot push sand. You have to pull sand." That is the principle of a any type of pumping machine, a vacuum cleaner., the heat exchanger in your refrigerator/freezer.

Have you thought of an experiment that might test your hypothesis of gravity turning repellent and then fading out?
Mimath224
5 / 5 (8) Oct 08, 2018
This is a pretty big deal for string theory because they fially have something where they make different predictions from the standard model (i.e. one can finally start going about devising experiments to see which one holds - or at thevery least which flavours of string theory can be ruled out)
1. A grand unified theory so flexible that it can be tweaked at a moment's notice to be unfalsifiable.

The entire point of the article is that this is no longer true.

Indeed. And another point is that any 'challenges' to the standard model would either show it is still the main theory or where any problems may be and what might replace it. Very interesting, definitely worth keeping an eye on.
Zzzzzzzz
1.4 / 5 (8) Oct 08, 2018
Another unproven, unverified, speculative guesstimate....Between galaxies there are "pockets" of primordial quantum universe not yet collapsed into spacetime. As they collapse into spacetime, they explode into our extant universe, driving expansion. These remaining "pockets" are smaller than singularities, but like black holes exhibit high gravity.

These remaining pockets are between galaxies, between places where spacetime has already bloomed, and none are left in those places where spacetime dominates.
Zzzzzzzz
1.4 / 5 (8) Oct 08, 2018
The two unproven, unverified, speculative guesstimates on here could even be combined, in an unproven, unverified, speculative guesstimated kind of way.....
Surveillance_Egg_Unit
1.8 / 5 (10) Oct 09, 2018
Hey SpookyOtto
Don't you ever get tired of slipping in and then out of your sox such as Zzzzzzzz just so that you can pretend you are someone else to make fools of the readers of your silly, inane posts? Don't you feel any shame in having more than a hundred different accounts with different account names to flood this once great science website?
A stupid old pussytard like you shouldn't even be in a science site. Perhaps a good cooking class would suit you better.
poksnee
1.5 / 5 (8) Oct 09, 2018
Two illogical theories tear each other apart (string theory and dark energy) this is a great chance for real physics to make a come back. The question is, are there any physicists with the intelligence to facilitate it?

danR is correct, but should add dark energy and matter.
Old_C_Code
2.1 / 5 (7) Oct 09, 2018
"There is an old engineer's saying "You cannot push sand. You have to pull sand."

See leaf blower.
Gibbo
1.4 / 5 (11) Oct 09, 2018
Why is everyone convinced that the universe is expanding?

It is equally possible that Time is slowing down and the distance is staying the same! Show proof otherwise.

If the distance is staying the same then there is no need for dark energy to exist because there is no expansion. All scientists seem to be very one-track minded when it comes to 'the universe is expanding' concept.

It's a simple case of swapping around that old equation that we learnt at school of Time, Distance, Speed.
antialias_physorg
4.1 / 5 (9) Oct 09, 2018
Show proof otherwise.

Because of Relativity? Time is not independent of space. That sort of view went out the window in the early 1900's
zz5555
4.5 / 5 (8) Oct 09, 2018
It is equally possible that Time is slowing down and the distance is staying the same! Show proof otherwise.

If time was slowing down universally, then you wouldn't see any shift because time would slow down for the photons as well. What you would need is for time to change elsewhere relative to earth. But even then you wouldn't see a shift because, again, time would change for the photons as well as they approached earth.

However, even if a redshift did somehow occur, it's unlikely that time is changing. This is because time isn't like velocity. With velocity, if two objects are moving away from each other, they both see the same redshift. With time, one object would see a redshift and the other a blueshift. The fact that we only see blueshift locally indicates that the universe is expanding.
vlaaing peerd
3 / 5 (3) Oct 09, 2018
This is a pretty big deal for string theory because they fially have something where they make different predictions


I agree and I always regarded DE as a bit of a of fudge factor without any good explanation and the need to introduce an additional force, yet we do see the universe expanding at an accelerating rate. So String theory needs another way to account for the expansion but I'm afraid any possible explanation would remain intestable because it probably involves a bigger or smaller scale of testing than we can currently do.

In regards to this article, I found this one from last year. https://phys.org/...ion.html

It explains the expanding universe with GR but without the need of DE. Though it's a bit complex to grasp for me I wonder if this in any way relates to what above String theorists have found.

torbjorn_b_g_larsson
4 / 5 (6) Oct 09, 2018
Vafa is productive of course, but the article is a bit problematic.

- Maybe Wrase got the problem - the standard model Higgs field breaks the conjecture - but he is the last author.
- Vafa's conjecture is only applicable to a deSitter approximation of an inflationary or late universe.
- The proposed "saved" conjecture is finetuned and only applicable to a non-standard Higgs field.
- The cosmology description is cringe-worthy and many decades out of use.

So this is useful for string theory and its "swampland" territory of approximative "cosmologies" (physics), but whether or not the problems of such approximation has any bearing on the real universe is less clear. Same with the non-Higgs conjecture breaker, since the LHC now have started to go from testing a standard Higgs particle to testing its generating fields - and they look like the standard theory field.

Nitpick on comments: String theory as math, still useful. String theory as physics, testing is still open AFAIU.
torbjorn_b_g_larsson
4.3 / 5 (7) Oct 09, 2018
Why is everyone convinced that the universe is expanding?


Because that is what the observations have said now, for over a century. I see you refer to several decades old ideas that died in the process for one reason or other. I think there is a reject for those specifically, but who cares any longer, they did not work. (Also, since local time is a parametrization, it is easy to see that "the local rate of time" is 1, i.e. constant.)
rrwillsj
1 / 5 (3) Oct 09, 2018
"Major" announcement...

Since Dark Matter is to be henceforth called "Majoron" particles...

It greatly amuses me to re-title "Dark Energy" as "Majorarcana".

You're welcome.
rrwillsj
1 / 5 (3) Oct 09, 2018
old_coot. If you put your hand in front of the leaf blowers nozzle? You would notice the expelled air feels warm to hot.

The blowing air you feel, that is pushing the leaves and trash about? Is coming from a pump that uses a vacuum effect to inhale/pull-in air, then push it back out as a concentrated stream. The "pull" is the cause. The "push" is the effect.

Do any of you fringe cranks have any real world experience?
Surveillance_Egg_Unit
3 / 5 (4) Oct 09, 2018
"Major" announcement...

Since Dark Matter is to be henceforth called "Majoron" particles...

It greatly amuses me to re-title "Dark Energy" as "Majorarcana".

You're welcome.
says rrwilliejoe

You left out the 'e' at the end and the space in between: Major arcane. Major pain also suits.

You're welcome.
Surveillance_Egg_Unit
1.8 / 5 (5) Oct 09, 2018
Why is everyone convinced that the universe is expanding?


Because that is what the observations have said now, for over a century. I see you refer to several decades old ideas that died in the process for one reason or other. I think there is a reject for those specifically, but who cares any longer, they did not work. (Also, since local time is a parametrization, it is easy to see that "the local rate of time" is 1, i.e. constant.)

says tbglarsson

It is a good thing that you stated that it is "the local rate of Time" as Time itself is also constant everywhere else in the Universe that is not affected by global rotations and the effects of gravity on Mass; but manmade Time clocks are only good insofar as the measurements of the Earth's daily rotations and orbits around the Sun.

And Time would be measured differently on every other planetary body when size/Mass/rotation/orbit differs from that of Earth, as well as distance from its Star.
Da Schneib
4 / 5 (4) Oct 09, 2018
My latest, unproven, unverified, speculative guesstimate is... The newly discovered (also unverified) "Majoron" particle that is hypothesized to be Dark Matter. Is claimed (unconfirmed) to be a product of the decay of tau & meson neutrinos.
What's a "meson neutrino?"
Da Schneib
3.7 / 5 (3) Oct 09, 2018
Looks like Vafa's conjectures have some problems.
Surveillance_Egg_Unit
1 / 5 (4) Oct 10, 2018
I was searching for any information about "Time Curvature". On the first page there was only one source, but a warning came up that the page was dangerous - so I beat a hasty retreat out of it. And, after 3 more pages, I still hadn't been able to find an exacting bit of information on the subject. But there were plenty of sites wrt "spacetime curvature".

I tend to believe that the term "spacetime" may have been used at the time when it was coined, as a catchall phrase only to conflate space with time, and to avoid having to use either one separately.
While it does save space in sentences/ideas, the conjoining of Space and Time, especially when "curvature" is added to it is, in my opinion, a bit of a fraud, since Time is unable to curve - while Space is very much curvy or curvable (under certain conditions).

Therefore, it is with great hopefulness that I look upon SpaceTime as a future possible resident in the trashcan of Physics history as Time moves on straightaway.
Ojorf
3 / 5 (4) Oct 10, 2018
I tend to believe that the term "spacetime" may have been used at the time when it was coined, as a catchall phrase only to conflate space with time, and to avoid having to use either one separately.
While it does save space in sentences/ideas, the conjoining of Space and Time, especially when "curvature" is added to it is, in my opinion, a bit of a fraud, since Time is unable to curve - while Space is very much curvy or curvable (under certain conditions).


Spacetime was "coined, as a catchall phrase only to conflate space with time, and to avoid having to use either one separately???

LOL!

Did you even go to school?

You don't have to believe anything, you can read up on it on the internet.
You are so confused with regards to relativity and space time. Why don't you read up on it?

That space and time are part and parcel of the same thing has been known for more than a century!

rrwillsj
3.7 / 5 (3) Oct 10, 2018
Da Schneib, you are correct. I confused meson with muon neutrino. Me bad! Hell, me sloppy! Thanks for pointing out my error.

https://phys.org/...ube.html
rrwillsj
2.3 / 5 (3) Oct 10, 2018
Oh, and I just realized. I have posted my error on several articles. Nine of the anti-science cranks, woo merchandisers and denier frauds caught my error.

It took someone Scientifically literate.

Good Show, Old Boy!
antigoracle
1 / 5 (2) Oct 10, 2018
"Major" announcement...

Since Dark Matter is to be henceforth called "Majoron" particles...

It greatly amuses me to re-title "Dark Energy" as "Majorarcana".

You're welcome.

The rrwillsj idiot (aka Major Moron) spews.
Do you not tire of soiling the forum with the shite between your ears.
Mark Thomas
3 / 5 (2) Oct 10, 2018
The antigoracle jackass brays again.
Hey jackass, your tiny, atrophied Republican troll brain is incapable of processing actual science, so just quit.
The shite between your ears is....well shite. Using it to soil the forum just makes your stench stronger. Accepting what the Republican Cult spew in your face, without question, just confirms your ignorance.

(Folks, I am trying to communicate with antigoracle in a manner he can understand. I tried sound reasoning backed up by links to reliable papers/articles, but it does not work.)
gunnqu
2.3 / 5 (3) Oct 11, 2018
RUNII: No SUSY, No WIMP, No HIGGS, No NEW PHYSICS?
http://vixra.org/...40v5.pdf
https://www.econo...ysicists
"Whether politicians and taxpayers will be up for this remains to be seen. That fundamental physics has got as far as it has is, essentially, a legacy of its delivery to political leaders of the mid-20th century of the atom and hydrogen bombs. The consequence of this was that physicists were able to ask for expensive toys—for who knew what else they might come up with. That legacy has now been spent, though, and any privilege physics once had has evaporated. This risks leaving in permanent limbo not only the GUTs and their brethren, but also the sceptical idea of Dr Hossenfelder that the Standard Model really is all there is. And that would surely be the most depressing result of all."?

https://youtu.be/uvHalv2f5oM
https://www.moreb.../gb/book
Surveillance_Egg_Unit
1 / 5 (2) Oct 11, 2018
@gunnqu
I must agree. I am not surprised that all of the previous discoveries are based on the Standard Model - whether it actually fits the first time, or not. If the maths/equations don't fit, well then, it is time for some new particles with new names - or some other new guesswork that will surely make it fit the Standard Model and GR/SR. The invisible is fully acceptable by the mainstream scientists.

If it STILL doesn't fit, then it would have to be something so unusual and unique that nobody can determine exactly what it is. And in the meantime - alternative science is laughed at and derided if it doesn't comply with the Standard Model or has been peer-reviewed and submitted and accepted to science journals.
Whydening Gyre
5 / 5 (1) Oct 11, 2018
old_coot. If you put your hand in front of the leaf blowers nozzle? You would notice the expelled air feels warm to hot.

Only of your using a gas model. And even then not very pronounced, as the moving of air has a cooling effect...
rrwillsj
1 / 5 (1) Oct 11, 2018
WG, mostly true but irrelevant to the discussion.

Oh auntieoracle. I thought as you are such a mushroom. Planted forever in the cold, dank dark. You would appreciate the soothing warmth of being blanketed with my bullshit!

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