{
  "id": 3567963,
  "title": "Richard Feynman’s 80-year-old quantum postulate has now been validated",
  "url": "https://urgent.news/2026/08/26/richard-feynmans-80-year-old-quantum-postulate-has-now-been-validated",
  "topic": "science",
  "section": "Science",
  "published": "2026-08-26T18:00:00.000Z",
  "source": {
    "name": "New Scientist",
    "slug": "new-scientist",
    "url": "https://www.newscientist.com/article/2586608-richard-feynmans-80-year-old-quantum-postulate-has-now-been-validated/"
  },
  "original_language": "en",
  "account": "Richard Feynman's \"path integral\" postulate, a crucial component of quantum physics, has been directly validated for the first time in an experiment. The principle, formulated by Feynman nearly 80 years ago, forms the foundation for much of modern physics. Quantum particles are notoriously challenging to analyze as measuring them alters their properties. However, researchers have developed sophisticated mathematical tools to predict how a particle will behave under specific conditions. One such tool is Feynman's path integral, which posits that the most likely path a quantum particle will take between two points can be determined by calculating all possible paths between those points in a specific manner. Since Feynman proposed the path integral in 1948, it has become a cornerstone in many scientific disciplines, including particle physics. For the first time, researchers at the South China Normal University have put Feynman's idea to the test in an experiment. They achieved this by building upon their previous work, which involved measuring another quantum object related to photons - the propagator. This object predicts how a photon's quantum state changes as it travels through a series of optical components such as mirrors, lenses, and crystals. Previously, the team had developed a method to measure different properties of photons and reconstruct their propagators. However, they realized that they could also construct a path integral for a given photon by measuring a succession of propagators and multiplying them together. Specifically, the researchers measured five propagators for a given photon across the experiment, leading to the measurement of 1,419,857 distinct paths. They then plugged all of these paths into Feynman's path integral formula to predict the photon's behavior, and found that it agreed perfectly with the photon's actual behavior. The researchers describe the result as \"astonishing\" given the success of Feynman's formulation over nearly eight decades. The experiment was challenging due to the sheer number of paths tested, which could have introduced errors and experimental noise. Despite these challenges, the team managed to significantly improve the precision of their experiment, making this a significant scientific advancement.",
  "summary": "Decades after it has been posited as a foundational principle of quantum physics, Richard Feynman’s “path integral” has been directly measured in an experiment for the first time.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}