quantum mechanics tagged posts

Scientists have created a miniature universe in the laboratory that could help answer one of the biggest mysteries in physics: What is time, and where does it come from? Using 24,000 ultracold atoms, a University of Birmingham researcher built an isolated quantum system that repeatedly expands and contracts, mimicking the Big Bang and a possible Big Crunch. Remarkably, the experiment showed that time could emerge from changes happening inside the system, without relying on an external clock.

What if time is not a fundamental part of the universe, but something that emerges from the changes taking place ins...

Quantum physics may place a fundamental limit on clock precision, hinting that time itself is not perfectly precise. Unconventional quantum theories may imply that time itself has a tiny fundamental uncertainty, placing an ultimate limit on how precisely any clock could measure it. The effect is far beyond current detection, but it could reveal a hidden connection between quantum mechanics, gravity, and spacetime.

Quantum mechanics has always challenged our everyday understanding of reality. In the quantum world, particles can exist in a superposition of states, meaning they can occupy multiple possible positions or configurations at the same time. Physicists describe these possibilities mathematically using a wavefunction.

That picture is very different from ordinary life, wher...

Researchers at UBC have found a way to mimic the elusive Schwinger effect using superfluid helium, where vortex pairs appear out of thin films instead of electron-positron pairs in a vacuum. Their work not only offers a cosmic laboratory for otherwise unreachable phenomena, but also changes the way scientists understand vortices, superfluids, and even quantum tunneling.

In 1951, physicist Julian Schwinger theorized that by applying a uniform electrical field to a vacuum, electron-positron pairs would be spontaneously created out of nothing, through a phenomenon called quantum tunneling.

The problem with turning the matter-out-of-nowhere theory into Star Trek replicators or transporters? Enormously high electric fields would be re...

Amid the many mysteries of quantum physics, subatomic particles don’t always follow the rules of the physical world. They can exist in two places at once, pass through solid barriers and even communicate across vast distances instantaneously. These behaviors may seem impossible, but in the quantum realm, scientists are exploring an array of properties once thought impossible.

In a new study, physicists at Brown University have now observed a novel class of quantum particles called fractional excitons, which behave in unexpected ways and could significantly expand scientists’ understanding of the quantum realm.

“Our findings point toward an entirely new class of quantum pa...