All posts tagged: quantum physics

Scientists observe ‘negative time’ for the first time in a quantum experiment

Scientists observe ‘negative time’ for the first time in a quantum experiment

Published by Jenni Sidey

A photon enters a cloud of atoms and emerges on the other side. When physicists calculate how long the atoms remained excited because of that transmitted photon, the answer falls below zero. University of Toronto researchers have turned that apparently impossible result into a laboratory measurement. Their experiment found a negative weak value for the time transmitted photons left atoms excited. It does not show light traveling backward through time, but it does show that a negative delay can govern a measurable physical interaction. The work was released in September 2024 by Daniela Angulo, Kyle Thompson, Vida-Michelle Nixon, Andy Jiao, Howard M. Wiseman and Aephraim M. Steinberg. Most worked through the University of Toronto, while Wiseman contributed from Griffith University in Australia. The experiment drew worldwide attention because it appeared to give physical meaning to a quantity often treated mainly as wave reshaping. On April 13, 2026, the work passed peer review and appeared in Physical Review Letters. The study, led by Professor Aephraim Steinberg at the University of Toronto, ignited considerable debate. (CREDIT: University …

The strange metals forcing us to rethink how electricity really works

The strange metals forcing us to rethink how electricity really works

Published by skeptic

In the mid-1980s, an unexpected discovery sparked one of the most frenzied episodes in scientific history. The finding in question was of materials that turned into superconductors – materials that conducted electricity with zero resistance – at much higher temperatures than had ever been seen before. Almost overnight, labs the world over shelved their existing research programmes and jumped on the bandwagon to find other examples. Newspapers heralded an impending age of lossless power transmission, floating trains and extraordinary supercomputers. A Nobel prize was handed out within a year. Amid all the fuss, it was easy to overlook another odd property of the new materials. Even when they were too warm to actually superconduct, they still conducted electricity in an odd way, with an unusual type of resistance that no theory could explain. What became known as strange-metal behaviour was an intriguing mystery for many researchers in the field, but was nonetheless a sideshow to the main drama of resistance disappearing entirely. Fast forward 40 years, and we still don’t understand high-temperature superconductivity, nor have …

Farewell, atom-smashing Large Hadron Collider

Farewell, atom-smashing Large Hadron Collider

Published by Jenni Sidey

Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. By signing up, you confirm you are 16+, will receive newsletters and promotional content and agree to our Terms of Use and acknowledge the data practices in our Privacy Policy. You may unsubscribe at any time. It’s difficult to overstate just how much the Large Hadron Collider (LHC) has helped advance our understanding of the universe. Since its debut in 2008, the 16.7-mile-wide subatomic smasher buried underneath Switzerland proved the existence of the Higgs boson particle (aka the God particle), highlighted the perplexing nature of muons, and even measured antimatter. Apocalyptic conspiracy theories to the contrary, it expanded on key concepts in quantum physics, while charting a path forward for researchers around the world. Still, all good things must come to an end. On June 29, CERN announced that the LHC had officially entered “Long Shutdown 3,” thus ceasing operations after 18 years of remarkable work. But in keeping with some of the most mindbending quantum physics concepts, the …

Meet the 15-year-old prodigy trying to unlock the secrets to human immortality

Meet the 15-year-old prodigy trying to unlock the secrets to human immortality

Published by Jenni Sidey

Laurent Simons is only 15, but he is already moving toward a goal that could shape the rest of his life. He wants to help people live longer and stay healthier. So far, that path has taken him through a PhD in quantum physics and into medical science, where he is now focusing on artificial intelligence. He does not describe that mission in dramatic terms. Instead, Simons talks about it like someone studying a system that has not been solved yet. “The way I look at death is as a huge puzzle with many pieces from many different fields, including biology, medicine, engineering, and physics, that haven’t been assembled yet,” said Simons. “My mission is to help put all of those pieces together.” That outlook grew from something personal. His grandparents have cardiovascular disease, and seeing that shaped the direction of his life early. Rather than accepting illness as something inevitable, he began thinking about what it would take to understand it more deeply. A Belgian teenager has earned a doctorate in quantum physics at …

A quantum state that lasts forever may finally be within our grasp

A quantum state that lasts forever may finally be within our grasp

Published by skeptic

In quantum states that theoretically last forever, particles get bounced around again and again, as if in a hall of mirrors Guy Bell/Alamy They say nothing lasts forever – but, hey, what do they know? Sure, the passing years soften the carvings on statues, pigments on paintings flake with age, and even the most formidable fortresses collapse eventually. But those are all features of the human-scale world. Things tend to work a touch differently in the quantum realm. For nigh on 70 years, physicists have been chasing the dream of quantum eternity: an arrangement of atoms positioned so that the quantum states between them are frozen forever, like light bouncing in a never-ending hall of mirrors. Proving that such a thing could exist wouldn’t just be an incredible scientific milestone, it would also be very handy indeed. Quantum states that last forever – or even just for a very long time – could enable us to create completely new states of matter, some of which could be the basis of powerful new quantum computers. “It …

‘Mini Universe’ built from ultracold atoms measures time without a clock

‘Mini Universe’ built from ultracold atoms measures time without a clock

Published by Jenni Sidey

A trapped cloud of ultracold atoms, colder than almost anything found in nature, has become the setting for a deceptively simple question: if a universe has no built-in clock, how could anything inside it tell what comes first and what comes next? That puzzle sits at the heart of a new experiment led by Professor Giovanni Barontini of the University of Birmingham. Working with about 24,000 rubidium atoms cooled to just a few billionths of a degree above absolute zero, Barontini built what he calls a “miniuniverse,” a closed quantum system designed to mimic a stripped-down version of the cosmos. The point was not to build a literal model of space itself. It was to test, in the lab, an idea that usually lives in the most abstract parts of theoretical physics: that time may not be a basic ingredient of the universe at all, but something that emerges from relationships and changes within it. “In some theories of the universe, especially quantum gravity, time doesn’t appear as a built-in feature. Yet in everyday life, …

Toy universe shows that time could be a quantum illusion

Toy universe shows that time could be a quantum illusion

Published by skeptic

Does time actually exist? Bruce Rolff/Stocktrek Images/Getty Images The passage of time may be nothing more than an illusion that emerges from the quantum interactions between different parts of the universe – at least, this is true in a toy model of the cosmos. The experiment may offer hints as to the nature of time in our own universe. Giovanni Barontini at the University of Birmingham, UK, started thinking about time while watching his 6-year-old son play. “He was building his own small universe, and I was thinking that that’s pretty much what we do also in our labs, when we build an ultracold-atoms system,” he says. “But then I was starting to think that this is also quite boring as a universe, because there’s not much going on there, and if nothing happens, it’s like if time is not passing by.” To investigate whether time is truly an illusion in such systems, Barontini used lasers and electromagnetic forces to cool around 20,000 rubidium atoms to temperatures close to absolute zero. He divided the atoms …

Atomic clocks may be powerful enough to detect the quantum fabric of time

Atomic clocks may be powerful enough to detect the quantum fabric of time

Published by Jenni Sidey

Time feels familiar. It marks every moment of daily life, from the ticking of a wall clock to the changing numbers on a smartphone screen. Yet despite its constant presence, time remains one of the deepest mysteries in science. For more than a century, physicists have known that time is not fixed. Albert Einstein’s theory of relativity showed that time can speed up or slow down depending on motion and gravity. The faster an object moves, or the closer it is to a massive object, the more differently it experiences time. But another revolution in physics, quantum mechanics, introduced an even stranger possibility. At the quantum level, particles can exist in multiple states at once through a phenomenon called superposition. If motion can exist in a superposition, then time itself may also flow in multiple ways simultaneously. Scientists have long wondered whether this bizarre idea is real. Until now, no experiment has been capable of testing it. Illustration of classical, semiclassical, and quantum proper time dynamics of a trapped-ion atomic clock that we consider. (CREDIT: …

Why we should all take quantum physics extremely personally

Why we should all take quantum physics extremely personally

Published by skeptic

Embracing quantum physics could make you see the world differently KamilSD / Alamy In December 2019, a bad tooth almost killed me. A terrible toothache turned into the biggest health crisis of my life, ultimately landing me in an intensive care unit for a week. Once I recovered, I had to make sense of why this happened to me. Personal negligence? Terrible luck? A fault of the US healthcare system? Rattled and unsure of how to feel, I turned to a place where I had long found answers to existential questions – quantum physics. Physics is often considered to be humanity’s oldest science, getting its start with early astronomers. Much of our understanding of the world is built on physics as a solid, rigorous, objective foundation. It is a science that breaks the world into pieces, analyses each of them, then reassembles them all into a whole that we understand better. This process, based on empiricism and mathematics, doesn’t care about feelings. Physics isn’t personal: for example, regardless of who you are, you cannot escape …

New tachyon theory could unlock the secrets of time travel and causality

New tachyon theory could unlock the secrets of time travel and causality

Published by Jenni Sidey

Faster-than-light particles have spent decades in physics as both temptation and warning. They offered a way to test the limits of Einstein’s relativity, but they also seemed to wreck the basic order of cause and effect. If something could outrun light, what would stop an effect from showing up before its cause? That question has kept tachyons, the long-hypothetical particles that would always move faster than light, on the edge of serious physics for more than half a century. A new paper from researchers at the University of Warsaw and the University of Oxford argues that the problem may not be the particles themselves, but the mathematical framework physicists have been using to describe them. In work published in Physical Review D, the team lays out a revised quantum field theory for tachyons that they say avoids several of the contradictions that pushed the idea to the margins. The paper does not claim tachyons have been found in nature. It does argue that they may not be forbidden by special relativity in the way many …