Inflation and Dark Energy: One Cosmic Spring? express
Right after the Big Bang, space swelled at an unimaginable speed — that's inflation. Now expansion has slowed, but galaxies are moving apart faster and faster. The culprit behind the acceleration has been named dark energy. Physicists propose: a single quantum field is responsible for both processes — like a compressed spring pervading the cosmos. The field interacts with gravity in a special way, so its energy does not wane as space expands.
To play this dual role, the field must be massive — about ten times heavier than the Planck mass. That's the mass of a speck of dust, yet for a quantum object it is enormous. This coincidence suggests: inflation and dark energy are not separate mysteries, but two sides of the same spring. The idea, proposed by Alan Guth for inflation and developed by Adam Riess for dark energy, is supported by new calculations.
Original abstract
as written by the authors arXiv:2605.14729v1
We study the regularized vacuum stress tensor of scalar fields in maximally symmetric spacetime and assess the feasibility of driving primordial inflation or current cosmic acceleration by analyzing the existence of solutions to the Friedmann equation. We find that a conformally coupled scalar field with mass of order $$10$$ $$M_{\text{pl}}$$ can be a candidate for both the inflaton and dark energy, suggesting that these two components may have the same quantum origin. In contrast, a minimally coupled scalar field cannot serve as either the inflaton or dark energy regardless of its mass.
The Planck mass — around 22 micrograms — is the weight of a grain of sand or a tiny droplet. For a quantum field, such a mass is huge, though to us it’s imperceptible.