Scientists Shrunk the Gap Between Atoms to an Astounding 50 Nanometers
When atoms get close together (like, really close together) strange quantum effects can take place.
A new study from MIT successfully placed two dysprosium atoms only 50 nanometers apart—10 times closer than previous studies—using “optical tweezers.”
This unprecedented closeness allowed scientists to observe effects such as thermalization and collective oscillation, and could help improve our understanding of quantum computing and superconductivity.
In quantum mechanics, the closer things are, the stranger things get. And that’s definitely true of a new MIT study that pushed the limits of atom proximity by a factor of ten.
This breakthrough moves beyond the previous proximity threshold established by the properties of a wavelength of light. After cooling the system to 1 microkelvin above absolute zero and amazingly squeezing two dysprosium atoms only 50 nanometers apart (a red blood cell is 1,000 nanometers wide, by the way), the atoms displayed exotic quantum states, including magnetic interactions 1,000 times stronger than if the atoms were the typical 500 nanometers apart. Utilizing a squeezing technique like this, scientists could better understand quantum phenomena such as superconductivity and superradiance.
“We have gone from positioning atoms from 500 nanometers to 50 nanometers apart, and there is a lot you can do with this,” MIT’s Wolfgang Ketterle, co-author of a study published in the journal Science earlier this month, said in a press statement. “At 50 nanometers, the behavior of atoms is so much different that we’re really entering a new regime here.”
One of those behaviors is an effect caused by an enhanced magnetic state called “thermalization,” where the two dysprosium atoms—used in this experiment for their ability to hold a “long-distance” connection with each other via dipole-to-dipole interactions—transferred heat between layers separated by a vacuum. Another side effect was “collective oscillation,” where the vibration of one layer caused the other layer to vibrate simultaneously. When the atoms separated from each other, both of these effects dissipated.
“Until now, heat between atoms could only by exchanged when they were in the same physical space and could collide,” MIT graduate student Li Du, the lead author of the study, said in a press statement. “Now we have seen atomic layers, separated by vacuum, and they exchange heat via fluctuating magnetic fields.”
Getting these two dysprosium atoms only 50 nanometers apart was no easy feat. According to Live Science, the team used the same approach as previous studies by employing an excellent-named technique known as an “optical tweezer,” which essentially creates an energy well in the laser that has the happy side effect of trapping atoms in place.
But to overcome the typical 500 nanometer boundary, the researchers used an inherent attribute of dysprosium, and trapped their atomic spins with “up” and “down” spin having different energies. This allowed the team to control the proximity of the two optical tweezers at their leisure, getting within 50 nanometers—and all stabilized through optical fiber.
The most obvious application of overcoming this quantum threshold is in the realm of quantum computing, especially in the creation of “magnetically-driven atomic systems for quantum computers,” according to the researchers. But the applications in the world of superconductors could be equally exciting.
Now that atoms can really cozy up with each other, there’s no telling what strange quantum effects future studies might discover.
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