22 May, 2024 by Pranjal Mehar
Collected at : https://www.techexplorist.com/new-approach-define-time-tunneling-particle/84086/
In quantum tunneling, particles move faster than light speed. But Darmstadt physicists think that the duration required for particles to tunnel has been calculated erroneously up until now. They propose a novel strategy for slowing down the speed of quantum particles.
Experiments where particles tunneled faster than light were once quite popular. After all, traveling faster than the speed of light is forbidden under Einstein’s theory of relativity. Therefore, whether the tunneling time was appropriately “stopped” in these trials.
TU Darmstadt physicists Prof. Enno Giese and Patrik Schach use a novel method to define “time” for a tunneling particle. They have now developed a fresh approach to calculating this time. Given the quantum nature of tunneling, they measured it in their experiment in a manner they felt was more appropriate.
Small particles, like atoms or light particles, have two natures, according to quantum theory.
Depending on the experiment, they exhibit wave-like or particle-like behavior. Quantum tunneling highlights the wave nature of particles. A “wave packet” moves toward the barrier like a water surge.
If the particle’s position were known, the height of the wave would represent the likelihood that it would manifest at this spot. A portion of the wave packet is reflected if it encounters an energy barrier. A tiny fraction does, however, pass through the barrier, and there is a slim chance that the particle will emerge on the other side.
According to earlier research, a light particle that has tunneled has traveled further than one that had a free path. As a result, it would have moved more quickly than light. But when the particle passed through, scientists had to pinpoint its location. They selected its wave packet’s highest point.
Enno Giese said, “But the particle does not follow a path in the classical sense. It is impossible to say where the particle is at a particular time. This makes it difficult to state the time required to get from A to B.”
Schach and Giese propose a clock made of the tunneling particle itself. As a reference, there is a second particle that does not tunnel. It is feasible to ascertain whether time passes more slowly, more quickly, or equally quickly during quantum tunneling by comparing these two natural clocks.
This technique is made possible by the particles’ wave nature. Wave oscillation and clock oscillation are comparable. Schach and Giese specifically suggest utilizing atoms as clocks. Atoms oscillate in their energy levels at specific frequencies. The atomic clock is initiated when a laser pulse is directed toward an atom, causing its levels to oscillate and be synchronized at first.
On the other hand, the beat slightly changes when tunneling. When a second laser pulse is applied, the two internal waves of the atom interfere. The elapsed time can be measured by measuring the distance between the two waves of the energy levels and detecting the interference.
According to Schach, the test is technically possible with current technology, but it presents a significant difficulty for experimenters. This is because the time difference that needs to be measured is incredibly short, just about 10-26 seconds. The scientist says that using clouds of atoms rather than single atoms as clocks is helpful. The impact can also be enhanced, for instance, by deliberately raising the clock frequency.
Giese said, “We are currently discussing this idea with experimental colleagues and are in contact with our project partners. It is quite possible that a team will soon decide to carry out this exciting experiment.”
Journal Reference:
- Patrik Schach, Enno Giese. A unified theory of tunneling times promoted by Ramsey clocks. Science Advances. DOI: 10.1126/sciadv.adl6078
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