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Physicists clocked the ghostly speed of quantum tunnelling

In quantum physics, there has always been suspense that how some particles travel from one place to another, passing impenetrable barriers, without having enough energy to do so. This question has puzzled the scientists for decades that how a particle can ‘tunnel‘ without energy.

In order to understand this process, scientists have been carrying out various experiments. In one such experiment using hydrogen atoms, it was seen that this ‘tunneling‘ process happens instantaneously. This instant tunneling has been investigated before as well, but now scientists have finally observed this process with the help of an instrument called the attoclock.

Robert Sang from Griffith University in Australia stated, “When we use atomic hydrogen, it is observed that there is no delay in what we can measure.”

The attoclock sets up 1,000 ultra-short pulses of light per second to interact with the hydrogen atom, pulses totaling 30 gigawatts of instantaneous power. This created a condition in which the single electron of the atom could be pushed through a barrier.

Sang said, “There’s a well-defined point where we can start that interaction, and there’s a point where we know where that electron should come out if it’s instantaneous. So anything that varies from that time we know that it’s taken that long to go through the barrier. That’s how we can measure how long it takes. It came out to agree with the theory within experimental uncertainty being consistent with instantaneous tunneling.”

It was one of the most mysterious studies of quantum mechanics that the scientists now have a better handle on. The new knowledge that the attoclock provides could be useful anywhere where quantum tunneling is involved including electron microscope and the transistor in our computers.

Quantum tunneling has also been suggested as a way of harvesting energy from excess radiation and waste heat, so more we understand the process of how it actually works, the better. The new researches can be carried out in order to understand how other kinds of atoms tunnel through the barriers and at what speed.

Now that we have learned this process, we can use this process for other atoms possibly to learn about new physics”, says one of the researchers, Igor Litvinyuk from Griffith University.

Published Researchhttps://www.nature.com/articles/s41586-019-1028-3