Truly Spooky: How Ghostly Quantum Particles Fly Through Barriers Almost Instantly

At the subatomic level Iphone Cases, particles can fly through seemingly impassable barriers like ghosts.

For decades, physicists have wondered just how long this so-called quantum tunneling takes LG Cases. Now, after a three-year investigation, an international team of theoretical physicists has an answer. They measured a tunneling electron from a hydrogen atom and found that its passage was practically instantaneous, according to a new study. [18 Times Quantum Particles Blew Our Minds]

Particles can pass through solid objects not because they’re very small (though they are), but because the rules of physics are different at the quantum level.

Imagine a ball rolling down a valley toward a slope as tall as Mount Everest; without a boost from a jetpack, the ball would never have enough energy to clear the hill. But a subatomic particle doesn’t need to go over the hill to get to the other side.

Particles are also waves, which extend infinitely in space. According to the so-called wave equation, this means that a particle may be found in any position on the wave.

Now picture the wave striking a barrier; it continues on through but loses energy, and its amplitude (the height of the peak) dips way down. But if the obstacle is thin enough, the wave’s amplitude doesn’t decay down to zero. As long as there’s still some energy left in the flattened wave, there’s some chance — albeit a small one — that a particle may fly through the hill and out the other side.

Conducting experiments that captured this elusive activity at the quantum level was “very challenging” to say the least, study co-author Robert Sang, an experimental quantum physicist and a professor at Griffith University in Australia, told Live Science in an email.

“You need to combine very complicated laser systems, a reaction microscope and a hydrogen atomic beam system to work all at the same time,” Sang said.

Their setup established three important reference points: the start of their interaction with the atom; the time that a freed electron was expected to emerge from behind a barrier; and the time when it actually appeared, Sang said in a video.