Rice University Team Recreates Fiery Birth of the Universe in Lab

A team led by Rice University physicist Frank Geurts has achieved a breakthrough by measuring the temperature of quark-gluon plasma (QGP) at multiple points during its evolution.

This form of matter is thought to have filled the universe only millionths of a second after the Big Bang, the event that marks the beginning and expansion of the cosmos, SciTechDaily reported.

For decades, scientists have sought reliable ways to measure temperatures in environments so extreme that no instrument could survive directly. (Photo: Brookhaven National Laboratory)

The research, published on October 14 in Nature Communications, sheds new light on how the early universe behaved under extreme heat and density.

For decades, scientists have sought reliable ways to measure temperatures in environments so extreme that no instrument could survive directly.

Geurts and his colleagues solved this problem by studying thermal electron-positron pairs created during high-speed heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in New York.

These emissions revealed the plasma’s internal temperature as it formed and cooled.

The study revealed two distinct average temperatures depending on the mass range of the dielectron pairs: a lower temperature of approximately 2.01 trillion Kelvin in the low-mass region, predicted by theoretical models and consistent with freeze-out temperatures from hadronic probes, and a significantly higher temperature of about 3.25 trillion Kelvin in the higher pair mass region.

This difference indicates that thermal radiation from the low-mass range, which creates these dielectrons, is predominantly emitted later, near the phase transition. In contrast, those from the higher mass range originate from the earlier, hotter stage of the QGP’s evolution.

“This work reports average QGP temperatures at two distinct stages of evolution and multiple baryonic chemical potentials, marking a significant advance in mapping the QGP’s thermodynamic properties,” Geurts said.