Quantum electrodynamics, or QED, describes how light interacts with charged particles — for example, electrons. It is one of the most precise theories in history: its predictions match experiment to the eleventh decimal place. But it has an unpleasant feature: when you try to calculate something more complex than a simple exchange of a single photon, the answers often blow up to infinity.

Usually, physicists resort to a procedure called 'renormalization': they manually subtract infinities, replacing them with measured values of mass and charge. This works but leaves the feeling of a patch on an elegant dress. The new work proposes to redesign the dress itself — to give all virtual particles a minimum possible lifetime.

The author builds a version of QED where every virtual history has a lower bound on proper time — a tiny interval associated with a very high energy Λ. This parameter is not removed at the end of calculations; it remains part of the theory. As a result, all amplitudes (quantities determining the probability of processes) become finite from the start. The familiar renormalization is replaced by 'finite fitting'—parameters are simply matched to experiment at some energy.

Most importantly, the theory passes a test on a process considered a benchmark: the production of two photons in a quark-antiquark collision. The final answer for this process does not change, despite all the reworking. It's as if the foundation of a building were replaced, and the upper floors remained exactly in place.