The Cosmic Loom: The Puzzle of Missing Antimatter and Inflation ✦
Original: "Nonthermal leptogenesis via cosmological gravitational particle production is tested by inflationary gravitational waves"
Gravitational particle production at the end of inflation explains why matter survived in the Universe and predicts a signature in relic gravitational waves.
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At the end of inflation, space expanded so rapidly that quantum fluctuations froze into real particles. Heavy neutrinos, born directly from the vacuum, became the detonator of the asymmetry — that tiny difference to which we owe our very existence. Today those events are imprinted not just in the distribution of galaxies, but in the trembling of spacetime itself. Future CMB polarization telescopes may yet hear this cosmic whisper, turning myth into a measurable quantity.
🎯 Gravitational production is when the expansion of spacetime pulls particles out of the vacuum. Today's Hubble scale is too small, but at the end of inflation it was enough to make the void spark with real particles.
Y_B \approx 10^{-10} \left(\frac{-\varepsilon}{10^{-1}\varepsilon_{\rm DI}}\right) \left(\frac{M_N}{10^{13}\,\text{GeV}}\right) \left(\frac{H_e}{10^{13}\,\text{GeV}}\right)^2 \left(\frac{T_{\rm RH}}{10^9\,\text{GeV}}\right)^{-1} \left( \frac{a^3 n_N / a_e^3 H_e^3}{10^{-3}} \right)
Y_B is the ratio of baryon density to entropy, ε is the CP violation parameter, M_N is the neutrino mass, H_e is the Hubble parameter at the end of inflation, T_RH is the reheating temperature, a^3 n_N is the density of produced neutrinos.
r \approx 1.6 \times 10^{-3} \left(\frac{H_e}{10^{13}\,\text{GeV}}\right)^2
r is the ratio of tensor to scalar perturbation amplitudes in the CMB, H_e is the Hubble scale.
Scientists
Alan GuthAndrei LindeGeorges LemaîtreJames PeeblesAdam RiessBrian Schmidtantimatter
inflation
gravitational waves
neutrino
Standard Model
cosmic microwave background
big bang
expansion of the universe
spacetime curvatureLaws
Friedmann equationsHubble's lawDirac equationNoether's theoremEinstein field equationsPlanck's law