# MIT and UCSB Expand Brownian Motion Theory to Relativistic Quarks in Primordial Plasma

- Published: 2026-11-06 16:09 UTC
- Section: Science › Physics
- Tags: quark gluon plasma, MIT theoretical physics, relativistic brownian motion, heavy quarks momentum, strong nuclear force, einstein brownian motion
- URL: https://realtech.media/news/rt-ab8bdcbd7a78a29ea30e7441_mit_and_ucsb/

**Physicists have calculated momentum distributions for heavy quarks traveling at near light speed, extending Einstein’s model.**

![MIT and UCSB Expand Brownian Motion Theory to Relativistic Quarks in Primordial Plasma](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/001600ece66f9fcc.webp)
*scinexx*

Physicists at the Massachusetts Institute of Technology and the University of California at Santa Barbara have developed a theoretical model describing how relativistic heavy particles move through quark-gluon plasma, according to news.mit.edu. Published in Physical Review Letters by Jean Du Plessis and Bruno Scheihing-Hitschfeld, the study addresses the mechanics of primordial matter that existed during the first microseconds after the Big Bang [1]. In particle accelerator experiments, droplets of this plasma are produced for tens of septillionths of a second through ion collisions, and tracking heavy quarks that traverse these droplets serves as a primary method to investigate the fluid's microscopic properties.

## Limits of classical Brownian motion

Albert Einstein formulated the foundational theory of Brownian motion in 1905, establishing that a particle suspended in a fluid maintains an equilibrium between drag forces and microscopic impacts from surrounding atoms. For over a century, this behavior was characterized by a standard bell-shaped probability distribution where moderate momentum changes dominate and extreme kicks decay symmetrically. However, physicists have noted over the past two decades that this equilibrium breaks down for particles moving at relativistic velocities close to the speed of light, as the traditional model fails to account for certain extreme relativistic interactions.

## Asymmetric momentum distributions

To move beyond classical Brownian models, the researchers analyzed scenarios involving a relativistic heavy quark moving through a gas of weakly interacting quarks and gluons, focusing on the strong nuclear force. Their calculations revealed that while small momentum shifts still conform to a bell curve, rare and unusually large momentum transfers deviate markedly from a Gaussian profile [1]. Furthermore, the model shows an asymmetry in force distribution: severe impacts that decelerate a fast-moving heavy quark occur more frequently than equally large impulses that accelerate it, providing a measurable signature for future heavy-ion experiments.

## Sources

1. [news.mit.edu](https://news.mit.edu/2026/pinning-down-quark-gluon-plasma-structure-1105)
2. [scinexx](https://www.scinexx.de/news/kosmos/urplasma-seltene-impulsstoesse-koennten-die-erste-fluessigkeit-des-universums-entschluesseln)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-ab8bdcbd7a78a29ea30e7441_mit_and_ucsb/