Physicists at MIT have created a time-reversal machine that can measure vibrating atoms. The vibrations between atoms hold a lot of information. And, if scientists can even figure out how to accurately measure those vibrations and how they change over time, then we could open new doors to information we’ve been able to harness before.
That’s the idea behind a new machine built by physicists at MIT. The machine can’t reverse time in the normal sense of letting people time travel. What it can do, though, is allow us to manipulate entangled atoms in a way that makes them evolve backward in time. It’s an interesting concept and one that could help in the hunt for evidence of dark matter.
MIT physicists built a time-reversal machine that could hunt for dark matter
One of the biggest benefits of the time-reversal machine and this technique, which the physicists call SATIN (signal amplification through time reversal), is improving the accuracy of atomic clocks. This technique is so effective that scientists believe it could improve our atomic clocks by a factor of 15. This would essentially make them so precise that they’d be less than 20 milliseconds off.
Further, the machine could help us in the hunt for dark matter. We know that dark matter exists. We’ve even discovered some possible candidates for dark matter. However, we’ve never actually discovered real evidence of the substance, which makes up 80 percent of our universe’s mass. The machine could also help us detect gravitational waves and other phenomena.
The physicists published a paper on the SATIN technique in the journal Nature. The paper showcases how the time-reversal machine lets them essentially bypass what we know as the Standard Quantum Limit. This limit is essentially the atom’s actual oscillation. However, it can be difficult to measure that kind of thing at the scale of a single atom.
But what does all of this matter, anyway? After all, how much does an atomic clock really affect an everyday person? Well, they really don’t, not in your typical sense. But understanding atoms better and even being able to detect dark matter and other phenomena is a benefit for all.
Improving our atomic clocks
With current state-of-the-art atomic clocks, physicists measure the oscillations of thousands of ultracold atoms. They do this multiple times, increasing their chance of accurately measuring the oscillations. (via PhysOrg) To improve this, the physicists at MIT used a time-reversal machine. Again, this isn’t really the type of thing you’d expect when hearing the words time machine.
But the machine allowed them to copy the evolution of the atom onto another atom. They could de-evolve another atom from here, forcing it back to its initial state. The entire process is somewhat intricate, but the basic gist is the scientists took two atoms and forced them to oscillate in a correlated state. Next, they took one of the atoms and forced it to de-evolve.
This essentially acted as a time-reversal mechanism for the second atom, showing them all the evolutions that the atom had made as it transformed back to its initial state. When measuring the difference between phases, they found notable changes, showcasing clear evidence that a quantum change had occurred somewhere in the atom’s evolution.
The physicists hope to be able to use this same technique on quantum sensors to aid in the hunt for evidence of dark matter and other phenomena.