The early universe was a fluid quark-gluon plasma

The early universe was a fluid quark-gluon plasma
Fig. 1 [Left] An event from the first Xenon-Xenon collision at the Large Hadron Collider at the top energy of the Large Hadron Collider (5.44 TeV ) registered by ALICE [credit: ALICE]. Every colored track (The blue lines) corresponds to the trajectory of a charged particle produced in a single collision; [right] formation of anisotropic flow in relativistic heavy-ion collisions due to the geometry of the hot and dense overlap zone (shown in red color). Credit: Niels Bohr Institute

Scientists from the Niels Bohr Institute, University of Copenhagen, and their colleagues from the international ALICE collaboration recently collided xenon nuclei, in order to gain new insights into the properties of the Quark-Gluon Plasma (the QGP) – the matter that the universe consisted of up to a microsecond after the Big Bang. The QGP, as the name suggests, is a special state consisting of the fundamental particles, the quarks, and the particles that bind the quarks together, the gluons. The result was obtained using the ALICE experiment at the 27 km long superconducting Large Hadron Collider (LHC) at CERN. The result is now published in Physics Letters B.

The particle physicists at the Niels Bohr Institute have obtained new results, working with the LHC, replacing the lead-ions, usually used for collisions, with Xenon-ions. Xenon is a "smaller" atom with fewer nucleons in its nucleus. When colliding ions, the scientists create a fireball that recreates the initial conditions of the universe at temperatures in excess of several thousand billion degrees. In contrast to the Universe, the lifetime of the droplets of QGP produced in the laboratory is ultra short, a fraction of a second (In technical terms, only about 10-22 seconds). Under these conditions the density of quarks and gluons is very large and a special state of matter is formed in which quarks and gluons are quasi-free (dubbed the strongly interacting QGP). The experiments reveal that the primordial matter, the instant before atoms formed, behaves like a liquid that can be described in terms of hydrodynamics.

"One of the challenges we are facing is that, in heavy ion collisions, only the information of the final state of the many particles which are detected by the experiments are directly available – but we want to know what happened in the beginning of the collision and first few moments afterwards," You Zhou, Postdoc in the research group Experimental Subatomic Physics at the Niels Bohr Institute, explains. "We have developed new and powerful tools to investigate the properties of the small droplet of QGP (early universe) that we create in the experiments." They rely on studying the spatial distribution of the many thousands of particles that emerge from the collisions when the quarks and gluons have been trapped into the particles that the Universe consists of today. This reflects not only the initial geometry of the collision, but is sensitive to the properties of the QGP. It can be viewed as a hydrodynamical flow." The transport properties of the Quark-Gluon Plasma will determine the final shape of the cloud of produced particles, after the collision, so this is our way of approaching the moment of QGP creation itself," You Zhou says.

Two main ingredients in the soup: Geometry and viscosity

The degree of anisotropic particle distribution – the fact that there are more in certain directions—reflects three main pieces of information: The first is, as mentioned, the initial geometry of the . The second is the conditions prevailing inside the colliding nucleons. The third is the shear viscosity of the Quark-Gluon Plasma itself. Shear viscosity expresses the liquid's resistance to flow, a key physical property of the matter created. "It is one of the most important parameters to define the properties of the Quark-Gluon Plasma," You Zhou explains, " because it tells us how strongly the gluons bind the quarks together ".

"With the new Xenon collisions, we have put very tight constraints on the theoretical models that describe the outcome. No matter the initial conditions, Lead or Xenon, the theory must be able to describe them simultaneously. If certain properties of the viscosity of the gluon plasma are claimed, the model has to describe both sets of data at the same time, says You Zhou. The possibilities of gaining more insight into the actual properties of the "primordial soup" are thus enhanced significantly with the new experiments. The team plans to collide other nuclear systems to further constrain the physics, but this will require significant development of new LHC beams.

"This is a collaborative effort within the large international ALICE Collaboration, consisting of more than 1800 researchers from 41 countries and 178 institutes." You Zhou emphasised.

Explore further

Small, short-lived drops of early universe matter

Journal information: Physics Letters B

Citation: The early universe was a fluid quark-gluon plasma (2018, October 5) retrieved 19 May 2019 from
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Oct 05, 2018
Are quarks bosons? If not then they could not have occupied a singularity...

Oct 05, 2018
Are quarks bosons? If not then they could not have occupied a singularity...

........quarks are simply a placeholder theory, none have ever been isolated, just more INFERRED Pop-Cosmology, like DM.

They are any of a number of subatomic particles carrying a fractional electric charge, postulated as building blocks of the hadrons. Quarks have not been directly observed, but theoretical predictions based on their existence have been confirmed experimentally. Due to a phenomenon known as color confinement, quarks are NEVER directly observed or found in isolation.

Oct 06, 2018
What a dipshit.

From his comment it is obvious he doesn't even know what a quark is supposed to be.
Well below the level of Pop-Cosmology in his understanding.

I mean:
"..quarks are simply a placeholder theory, none have ever been isolated"
LOL, see!

Then he posts a link that proves his own BS wrong!

What a unique character we have here, flaunting his ignorance and seemingly proud of it.

Oct 07, 2018
Robert, simple answer, no. Quarks constitute Hadrons.

Bosons are a separate issue.

I am not sure why you mentioned singularities. That's an entirely different issue to attempt to understand.

Oct 10, 2018
"........quarks are simply a placeholder theory, none have ever been isolated, just more INFERRED Pop-Cosmology, like DM."

"postulated as building blocks of the hadrons. Quarks have not been directly observed....quarks are NEVER directly observed or found in isolation." The gist of Bennis post...

"Then he posts a link that proves his own BS wrong!"

Interesting....below from the link:

"quarks are never directly observed or found in isolation;"

I guess some people cannot get the point unless you stab them with it.

Oct 11, 2018
And pill, you have the perfectly pointed pinhead for spreading balderdash and stuporstition. If you plonk a colorful pinwheel on your zippy point?

You could run around, making the propeller spin the rainbow. While shouting "Woo! Woo! I got the Woo!"

And finally you will impress peoole with... Hmm... Not scientific acumen, that's for damn sure.

I know! You will impress everybody who has the misfortune to reside near your hoovertrumpville. That you can stagger about and screech incomprehensible gibberish. Simultaneously.

Oh wait. Doesn't "simultaneity" violate some of your cult's sacred doctrines?

Oct 11, 2018
Are quarks bosons? If not then they could not have occupied a singularity...

Because they never did.
Also, aren't bosons theoretically able to occupy the same space as other bosons?

Oct 11, 2018
Are quarks bosons? If not then they could not have occupied a singularity...
No. Quarks are fermions. Otherwise hadrons wouldn't be fermions. Gluons are bosons.

I don't know why you think fermions couldn't come from a singularity, or why there's even any reason to believe there is or ever was a true singularity (as opposed to a coordinate singularity, which is an artifact of math, not of real interactions).

Oct 18, 2018
The point of my question was to relate the hypothetical initial singularity, still present in Big Bang cosmology, with the initial quark-gluon plasma hypothesized in this article. Pauli exclusion principle says that only bosons can occupy the same space and so only bosons can occupy a singularity.

In Black Hole theory there is a hypothetical phenomena called 'bosonization' whereby fermions can become bosons but this is highly speculative and there is no evidence to date that it can actually happen.

I am personally sceptical that a boson can occupy a space smaller than its wavelength.

So there is no mechanism by which matter can either enter or emerge from a singularity. Big Bang Cosmology circumvents the problem by apply a cutoff point at Planck the scale, so the universe is already Planck's time in age and Planck Length in diameter. More of an excuse than a solution...papering over the gaping holes in current model...

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