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Particles Play Shy in an Expanding Universe ⚡ экспресс

Original: "Quantum dynamics of cosmological particle production: interacting quantum field theories with matrix product states"
arXiv:2601.02331v2 · 2026-01-05 · CC BY · ⏱ 1 min · HEP Theory Cosmology HEP Lattice HEP Phenomenology
Particles in an expanding universe actually put the brakes on their own creation when they interact, upending decades of cosmic lore.
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The expansion of the universe is like a dance floor stretching wider. For decades, physicists assumed that more stretching would spawn more particles—like the floor spontaneously generating new dancers. But those models ignored an obvious fact: dancers sometimes link arms. When particles interact, new simulations reveal, they actually suppress creation. It's as if paired dancers block the floor, making it harder for newcomers to join. The team modeled two types of interacting particles in curved spacetime: one where they connected like springs, another where they twisted like tiny magnets. In both cases, interactions put the brakes on particle birth. Even entanglement—the invisible thread binding fates—behaved oddly: in the springy case, it grew sluggishly; in the magnetic one, it tightened even as numbers fell. As Stephen Hawking highlighted, entropy and quantum effects intertwine, and these results nod to that deep link. The cosmic shyness rewrites the Big Bang's story: the infant universe may have simmered more quietly, with fewer particles than thought.

🎯 The idea that an expanding universe can create particles from nothing was first aired by [scientist:Erwin Schrödinger]Erwin Schrödinger[/scientist] in 1939, long before [scientist:Stephen Hawking]Hawking[/scientist] applied it to black holes.

Scientists
Alan GuthAndrei LindeGeorges LemaîtreJames PeeblesAdam RiessBrian Schmidt
Tags
expansion of the universe spacetime curvature entropy big bang
Laws
Friedmann equationsHubble's lawsecond law of thermodynamicsBekenstein-Hawking entropyEinstein field equationsPlanck's law
Original: arXiv:2601.02331v2 · CC BY · bridge42worlds