Scientists observe ‘negative time’ in quantum experiments

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Updated 22 December 2024

Scientists observe ‘negative time’ in quantum experiments

Photo/Shutterstock
  • The researchers emphasize that these perplexing results highlight a peculiar quirk of quantum mechanics rather than a radical shift in our understanding of time

TORONTO, Canada: Scientists have long known that light can sometimes appear to exit a material before entering it — an effect dismissed as an illusion caused by how waves are distorted by matter.
Now, researchers at the University of Toronto, through innovative quantum experiments, say they have demonstrated that “negative time” isn’t just a theoretical idea — it exists in a tangible, physical sense, deserving closer scrutiny.
The findings, yet to be published in a peer-reviewed journal, have attracted both global attention and skepticism.
The researchers emphasize that these perplexing results highlight a peculiar quirk of quantum mechanics rather than a radical shift in our understanding of time.
“This is tough stuff, even for us to talk about with other physicists. We get misunderstood all the time,” said Aephraim Steinberg, a University of Toronto professor specializing in experimental quantum physics.
While the term “negative time” might sound like a concept lifted from science fiction, Steinberg defends its use, hoping it will spark deeper discussions about the mysteries of quantum physics.

Years ago, the team began exploring interactions between light and matter.
When light particles, or photons, pass through atoms, some are absorbed by the atoms and later re-emitted. This interaction changes the atoms, temporarily putting them in a higher-energy or “excited” state before they return to normal.
In research led by Daniela Angulo, the team set out to measure how long these atoms stayed in their excited state. “That time turned out to be negative,” Steinberg explained — meaning a duration less than zero.
To visualize this concept, imagine cars entering a tunnel: before the experiment, physicists recognized that while the average entry time for a thousand cars might be, for example, noon, the first cars could exit a little sooner, say 11:59 am. This result was previously dismissed as meaningless.
What Angulo and colleagues demonstrated was akin to measuring carbon monoxide levels in the tunnel after the first few cars emerged and finding that the readings had a minus sign in front of them.

The experiments, conducted in a cluttered basement laboratory bristling with wires and aluminum-wrapped devices, took over two years to optimize. The lasers used had to be carefully calibrated to avoid distorting the results.
Still, Steinberg and Angulo are quick to clarify: no one is claiming time travel is a possibility. “We don’t want to say anything traveled backward in time,” Steinberg said. “That’s a misinterpretation.”
The explanation lies in quantum mechanics, where particles like photons behave in fuzzy, probabilistic ways rather than following strict rules.
Instead of adhering to a fixed timeline for absorption and re-emission, these interactions occur across a spectrum of possible durations — some of which defy everyday intuition.
Critically, the researchers say, this doesn’t violate Einstein’s theory of special relativity, which dictates that nothing can travel faster than light. These photons carried no information, sidestepping any cosmic speed limits.

The concept of “negative time” has drawn both fascination and skepticism, particularly from prominent voices in the scientific community.
German theoretical physicist Sabine Hossenfelder, for one, criticized the work in a YouTube video viewed by over 250,000 people, noting, “The negative time in this experiment has nothing to do with the passage of time — it’s just a way to describe how photons travel through a medium and how their phases shift.”
Angulo and Steinberg pushed back, arguing that their research addresses crucial gaps in understanding why light doesn’t always travel at a constant speed.
Steinberg acknowledged the controversy surrounding their paper’s provocative headline but pointed out that no serious scientist has challenged the experimental results.
“We’ve made our choice about what we think is a fruitful way to describe the results,” he said, adding that while practical applications remain elusive, the findings open new avenues for exploring quantum phenomena.
“I’ll be honest, I don’t currently have a path from what we’ve been looking at toward applications,” he admitted. “We’re going to keep thinking about it, but I don’t want to get people’s hopes up.”


Teen behind the Louvre heist ‘Fedora Man’ photo embraces his mystery moment

Teen behind the Louvre heist ‘Fedora Man’ photo embraces his mystery moment
Updated 09 November 2025

Teen behind the Louvre heist ‘Fedora Man’ photo embraces his mystery moment

Teen behind the Louvre heist ‘Fedora Man’ photo embraces his mystery moment
  • A photo of Pedro Elias Garzon Delvaux at the Louvre on the day of the crown jewels heist had drawn millions of views
  • The image shows him in a fedora and three-piece suit, sparking online speculation that he was a detective or even AI-generated

PARIS: When 15-year-old Pedro Elias Garzon Delvaux realized a photo of him at the Louvre on the day of the crown jewels heist had drawn millions of views, his first instinct was not to rush online and unmask himself.
Quite the opposite. A fan of Sherlock Holmes and Hercule Poirot who lives with his parents and grandfather in Rambouillet, 30 kilometers from Paris, Pedro decided to play along with the world’s suspense.
As theories swirled about the sharply dressed stranger in the “Fedora Man” shot – detective, insider, AI fake – he decided to stay silent and watch.
“I didn’t want to say immediately it was me,” he said. “With this photo there is a mystery, so you have to make it last.”
For his only in-person interview since that snap turned him into an international curiosity, he appeared for the AP cameras at his home much as he did that Sunday: in a fedora hat, Yves Saint Laurent waistcoat borrowed from his father, jacket chosen by his mother, neat tie, Tommy Hilfiger trousers and a restored, war-battered Russian watch.
The fedora, angled just so, is his homage to French Resistance hero Jean Moulin.
In person, he is a bright, amused teenager who wandered, by accident, into a global story.
From photo to fame
The image that made him famous was meant to document a crime scene. Three police officers lean on a silver car blocking a Louvre entrance, hours after thieves carried out a daylight raid on French crown jewels. To the right, a lone figure in a three-piece suit strides past – a flash of film noir in a modern-day manhunt.
The Internet did the rest. “Fedora Man,” as users dubbed him, was cast as an old-school detective, an inside man, a Netflix pitch – or not human at all. Many were convinced he was AI-generated.
Pedro understood why. “In the photo, I’m dressed more in the 1940s, and we are in 2025,” he said. “There is a contrast.”
Even some relatives and friends hesitated until they spotted his mother in the background. Only then were they sure: The Internet’s favorite fake detective was a real boy.
The real story was simple. Pedro, his mother and grandfather had come to visit the Louvre.
“We wanted to go to the Louvre, but it was closed,” he said. “We didn’t know there was a heist.”
They asked officers why the gates were shut. Seconds later, AP photographer Thibault Camus, documenting the security cordon, caught Pedro midstride.
“When the picture was taken, I didn’t know,” Pedro said. “I was just passing through.”
Four days later, an acquaintance messaged: Is that you?
“She told me there were 5 million views,” he said. “I was a bit surprised.” Then his mother called to say he was in The New York Times. “It’s not every day,” he said. Cousins in Colombia, friends in Austria, family friends and classmates followed with screenshots and calls.
“People said, ‘You’ve become a star,’” he said. “I was astonished that just with one photo you can become viral in a few days.”
An inspired style
The look that jolted tens of millions is not a costume whipped up for a museum trip. Pedro began dressing this way less than a year ago, inspired by 20th-century history and black-and-white images of suited statesmen and fictional detectives.
“I like to be chic,” he said. “I go to school like this.”
In a sea of hoodies and sneakers, he shows up in a three-piece suit. And the hat? No, that’s its own ritual. The fedora is reserved for weekends, holidays and museum visits.
At his no-uniform school, his style has already started to spread. “One of my friends came this week with a tie,” he said.
He understands why people projected a whole sleuth character onto him: improbable heist, improbable detective. He loves Poirot – “very elegant” – and likes the idea that an unusual crime calls for someone who looks unusual. “When something unusual happens, you don’t imagine a normal detective,” he said. “You imagine someone different.”
That instinct fits the world he comes from. His mother, Félicité Garzon Delvaux, grew up in an 18th-century museum-palace, daughter of a curator and an artist – and regularly takes her son to exhibits.
“Art and museums are living spaces,” she said. “Life without art is not life.”
For Pedro, art and imagery were part of everyday life. So when millions projected stories onto a single frame of him in a fedora beside armed police at the Louvre, he recognized the power of an image and let the myth breathe before stepping forward.
He stayed silent for several days, then switched his Instagram from private to public.
“People had to try to find who I am,” he said. “Then journalists came, and I told them my age. They were extremely surprised.”
He is relaxed about whatever comes next. “I’m waiting for people to contact me for films,” he said, grinning. “That would be very funny.”
In a story of theft and security lapses, “Fedora Man” is a gentler counterpoint – a teenager who believes art, style and a good mystery belong to ordinary life. One photo turned him into a symbol. Meeting him confirms he is, reassuringly, real.
“I’m a star,” he says – less brag than experiment, as if he’s trying on the words the way he tries on a hat. “I’ll keep dressing like this. It’s my style.”