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Quantum physicists recently discovered a perplexing phenomenon they have dubbed "negative time." The study was reported by Scientific American, but has not yet been peer reviewed. Researchers claim they were able to observe photons display this baffling temporal behavior in reaction to what's known as atomic excitation. As per Scientific American, photons that were beamed into a cloud of atoms, appeared to exit the cloud before they entered it. "A negative time delay may seem paradoxical, but what it means is that if you built a 'quantum' clock to measure how much time atoms are spending in the excited state, the clock hand would, under certain circumstances, move backward rather than forward," Josiah Sinclair, postdoc research fellow at MIT. |
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From The Scientific American Quantum physicists are familiar with wonky, seemingly nonsensical phenomena: atoms and molecules sometimes act as particles, sometimes as waves; particles can be connected to one another by a “spooky action at a distance,” even over great distances; and quantum objects can detach themselves from their properties like the Cheshire Cat from Alice’s Adventures in Wonderland detaches itself from its grin. Now researchers led by Daniela Angulo of the University of Toronto have revealed another oddball quantum outcome: photons, wave-particles of light, can spend a negative amount of time zipping through a cloud of chilled atoms. In other words, photons can seem to exit a material before entering it. “It took a positive amount of time, but our experiment observing that photons can make atoms seem to spend a *negative* amount of time in the excited state is up!” wrote Aephraim Steinberg, a physicist at the University of Toronto, in a post on X (formerly Twitter) about the new study, which was uploaded to the preprint server arXiv.org on September 5 and has not yet been peer-reviewed. The idea for this work emerged in 2017. At the time, Steinberg and a lab colleague, then doctoral student Josiah Sinclair, were interested in the interaction of light and matter, specifically a phenomenon called atomic excitation: when photons pass through a medium and get absorbed, electrons swirling around atoms in that medium jump to higher energy levels. When these excited electrons lapse to their original state, they release that absorbed energy as reemitted photons, introducing a time delay in the light’s observed transit time through the medium. Full Article @ Scientific American Time might be a mirage created by quantum physics, study suggestsPhysicists have struggled to understand the nature of time since the field began. But a new theoretical study suggests time could be an illusion woven at the quantum level.Time may not be a fundamental element of the universe but rather an illusion emerging from quantum entanglement, a new study suggests.Time is a thorny problem for physicists; its inconsistent behavior between our best theories of the universe contributes to a deadlock preventing researchers from finding a "theory of everything," or a framework to explain all of the physics in the universe. But in the new study, researchers suggest they may have found a clue to solving that problem: by making time a consequence of quantum entanglement, the weird connection between two far-apart particles. The team published their findings May 10 in the journal Physical Review A. Full Article @ Live Science |