Time Swapping - Slits in Time

A new diffracton study sends lasers through 'slits in time' in a novel take on the classic double slit experiment. (Image credit: Thomas Angus, Imperial College London)

In a first, scientists have shown that they can send light through "slits" in time.


The new experiment is a twist on a 220-year-old demonstration, in which light shines through two slits in a screen to create a unique diffraction pattern across space, where the peaks and troughs of the light wave add up or cancel out. In the new experiment, researchers created a similar pattern in time, essentially changing the color of an ultrabrief laser pulse.

The findings pave the way for advances in analog computers that manipulate data imprinted on beams of light instead of digital bits - it might even make such computers "learn" from the data. They also deepen our understanding of the fundamental nature of light and its interactions with materials.

For the new study, described April 3 in the journal Nature Physics(opens in new tab), the researchers used indium tin oxide (ITO), the material found in most phone screens. 

Scientists already knew ITO could change from transparent to reflective in response to light, but the researchers found it occurs much faster than previously thought, in less than 10 femtoseconds (10 millionths of a billionth of a second).

"This was a very big surprise and at the beginning it was something that we couldn’t explain," study lead author Riccardo Sapienza(opens in new tab), a physicist at the Imperial College London, told Live Science. 

Eventually, the researchers figured out why the reaction happened so fast by scrutinizing the theory of how the electrons in ITO respond to incident light. "But it took us a long time to understand it."  READ MORE...

Magic Mushrooms

Psilocybin, the hallucinogenic compound found in "magic mushrooms," could treat depression by creating a hyper-connected brain.

By boosting connectivity between different areas of the brain, the psychedelic may help people with depression break out of rigid, negative patterns of thinking, a new study suggests.

Recent clinical trials have suggested that psilocybin may be an effective treatment for depression, when carefully administered under the supervision of mental health professionals. In the new study, published Monday (April 11) in the journal Nature Medicine, researchers probed exactly how the psychedelic works to improve peoples' depressive symptoms. To do so, the team collected brain scans from about 60 patients who had participated in clinical trials for psilocybin therapy; these brain scans revealed distinct changes in the patients' brain wiring that emerged after they took the drug.

"We see connectivity between various brain systems increasing dramatically," first author Richard Daws, who was a doctoral student at Imperial College London at the time of the study, told Live Science. Healthy individuals with high levels of well-being and cognitive function tend to have highly connected brains, studies suggest, but in people with depression, "we sort of see the opposite of that — a brain characterized by segregation," said Daws, now a postdoctoral research associate at King's College London. This sort of organization undermines the brain's ability to dynamically switch between different mental states and patterns of thinking, he said.

The study supports the idea that psilocybin relieves depressive symptoms, at least in part, by boosting connectivity between different brain networks, said Dr. Hewa Artin, the chief resident of outpatient psychiatry at the UC San Diego School of Medicine, who was not involved in the study. That said, "additional studies will be needed to replicate results and validate findings," Artin told Live Science in an email.  READ MORE...