February 26, 2024

Solving a Cosmic Conundrum: “Perfect Fluid” Brings Us Closer to Understanding How Our Universe Began

How to Catch a Perfect Wave: Scientists Take a Closer Look Inside the Perfect Fluid
Berkeley Lab research brings us closer to comprehending how our universe began.
Researchers have actually reported new clues to solving a cosmic dilemma: How the quark-gluon plasma– natures perfect fluid– evolved into matter.

Scientists postulated that highly energetic jets of particles fly through the quark-gluon plasma– a droplet the size of an atoms nucleus– at speeds much faster than the velocity of sound, and that like a fast-flying jet, emit a supersonic boom called a Mach wave. Outcomes from those critical research studies revealed that these jets scatter and lose energy as they propagate through the quark-gluon plasma.
Where did the jet particles journey begin within the quark-gluon plasma? Once the diffusion wake is located in the quark-gluon plasma, you can differentiate its signal from the other particles in the background.
Their work will likewise assist experimentalists at the LHC and RHIC comprehend what signals to look for in their quest to understand how the quark-gluon plasma– natures best fluid– developed into matter.

A couple of millionths of a second after the Big Bang, the early universe took on an unusual brand-new state: a subatomic soup called the quark-gluon plasma.
And simply 15 years back, a worldwide team consisting of researchers from the Relativistic Nuclear Collisions (RNC) group at Lawrence Berkeley National Laboratory (Berkeley Lab) discovered that this quark-gluon plasma is a perfect fluid — in which gluons and quarks, the structure blocks of protons and neutrons, are so strongly coupled that they stream nearly friction-free.
View time-lapse video clip showing a supersonic Mach wave as it progresses in a broadening quark-gluon plasma. The computer system simulation provides new insight into how matter formed during the birth of the early universe. Credit: Berkeley Lab
Scientists postulated that extremely energetic jets of particles fly through the quark-gluon plasma– a droplet the size of an atoms nucleus– at speeds faster than the speed of noise, and that like a fast-flying jet, emit a supersonic boom called a Mach wave. To study the properties of these jet particles, in 2014 a team led by Berkeley Lab scientists originated an atomic X-ray imaging method called jet tomography. Arise from those critical research studies exposed that these jets scatter and lose energy as they propagate through the quark-gluon plasma.
But where did the jet particles journey begin within the quark-gluon plasma? A smaller sized Mach wave signal called the diffusion wake, scientists predicted, would inform you where to look. But while the energy loss was easy to observe, the Mach wave and accompanying diffusion wake stayed evasive.
In 2005, RHIC physicists announced that matter produced in the accelerators most energetic crashes acts like an almost best liquid. The properties of this fluid, the quark-gluon plasma, assist us to comprehend the residential or commercial properties of matter in the early universe.
Now, in a research study published just recently in the journal Physical Review Letters, the Berkeley Lab scientists report brand-new outcomes from model simulations revealing that another technique they developed called 2D jet tomography can help scientists locate the diffusion wakes ghostly signal.
” Its signal is so small, its like searching for a needle in a haystack of 10,000 particles. For the first time, our simulations reveal one can utilize 2D jet tomography to get the tiny signals of the diffusion wake in the quark-gluon plasma,” stated research study leader Xin-Nian Wang, a senior researcher in Berkeley Labs Nuclear Science Division who was part of the international team that invented the 2D jet tomography method.
To find that supersonic needle in the quark-gluon haystack, the Berkeley Lab team chose through numerous thousands of lead-nuclei collision occasions simulated at the Large Hadron Collider (LHC) at CERN, and gold-nuclei collision occasions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Some of the computer system simulations for the existing study were carried out at Berkeley Labs NERSC supercomputer user facility.
The jet particles supersonic signal has a special shape that looks like a cone– with a diffusion wake trailing behind, like ripples of water in the wake of a fast-moving boat. Once the diffusion wake is located in the quark-gluon plasma, you can distinguish its signal from the other particles in the background.
Their work will also help experimentalists at the LHC and RHIC comprehend what signals to look for in their quest to comprehend how the quark-gluon plasma– natures ideal fluid– developed into matter. This is still a work in development, but our simulations of the long-sought diffusion wake get us closer to addressing these concerns,” he stated.
Reference: “Search for the Elusive Jet-Induced Diffusion Wake in Z/ γ-Jets with 2D Jet Tomography in High-Energy Heavy-Ion Collisions” by Wei Chen, Zhong Yang, Yayun He, Weiyao Ke, Long-Gang Pang and Xin-Nian Wang, 17 August 2021, Physical Review Letters.DOI: 10.1103/ PhysRevLett.127.082301.
Extra co-authors were Wei Chen, University of Chinese Academy of Sciences; Zhong Yang, Central China Normal University; Yayun He, Central China Normal University and South China Normal University; Weiyao Ke, Berkeley Lab and UC Berkeley; and Longgang Pang, Central China Normal University.
NERSC is a DOE Office of Science user center at Berkeley Lab.
This work was supported by the DOE Office of Science and Office of Nuclear Physics.