Patrik Schach and Enno Giese, physicists at TU Darmstadt, are looking to redefine time—they believe our previous measurements may have been inaccurate. The researchers have arrived at this proposal thanks to the phenomenon of quantum tunneling, where particles appear to move faster than the speed of light.
We make sense of the world around us with classical mechanics. In this realm, the laws of physics reign supreme, and particles tend to follow them. Dig a bit deeper into the quantum realm, though, and even the theory of relativity comes crashing down.
The faster-than-light travel of particles inside a quantum tunnel has prompted researchers to question whether we have accurately measured time. Schach and Giese have proposed a new experimental design to measure time for a tunneling particle, considering its unique abilities in the quantum realm.
What is quantum tunneling?
In classical physics, a particle such as an electron can only pass through a potential energy barrier if it has the energy to overcome it. On the other hand, in quantum mechanics, the particle can cross over such a barrier even if its energy levels are lower. This is referred to as quantum tunneling.
This is attributed to the particle’s wave-like properties in quantum mechanics, which allow it to “tunnel” through the barrier even at a lower energy level. According to quantum mechanics, this tunneling is subjective to the width and height of the barrier and the particle’s energy.
Even though tunneling also seems to break the laws of energy conservation, the particle appears on the other side of the barrier with the same energy as before. So, no energy is gained or lost during the process.
Researchers believe that tunneling also plays a role in radioactive decay, allowing particles to escape the nucleus even though they do not have sufficient energy to escape the nuclear potential barrier. Additionally, the phenomenon could help serve applications such as microscopy and memory storage.
According to quantum mechanics, atoms can behave like waves and particles simultaneously. Their wave nature can help them overcome an energy barrier. However, when atoms are tunneling, it becomes difficult to predict when they will appear on the other side, i.e., when they need to tunnel.
Novel experimental design
Instead of relying on conventional approaches to measure time, Schach and Giese propose using the tunneling particle as a clock. A non-tunneling particle will serve as a reference in such a setup.
By comparing these two natural clocks, the researchers aim to determine whether time travels faster, slower, or equally fast when the particle is tunneling.
The researchers plan to use the oscillating energy levels between atoms to achieve this. Using a laser pulse, the researchers will oscillate the atoms and start the clock. During tunneling, a small shift in the rhythm occurs, and a second laser pulse will be used to cause the waves to interfere.
By measuring the interference, the team can precisely measure the elapsed time. The challenge, however, is that the time difference to be measured is extremely short, 10-26 seconds. To overcome this, the researchers propose using clouds of atoms instead of individual atoms to amplify the effect.
The experimental design has been published in the journal Science Advances.
ABOUT THE EDITOR
Ameya Paleja Ameya is a science writer based in Hyderabad, India. A Molecular Biologist at heart, he traded the micropipette to write about science during the pandemic and does not want to go back. He likes to write about genetics, microbes, technology, and public policy.
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
