Proximity governs the strength of interactions in the quantum realm. To explore exotic states of matter and engineer novel quantum materials, scientists strive to bring atoms as close as possible. Quantum simulators, which mimic the behavior of quantum systems, rely on this close proximity. However, conventional methods using laser light to manipulate atoms have been limited by the wavelength of light, typically allowing inter-atomic distances no smaller than 500 nanometers.
Researchers at MIT have shattered this limitation, demonstrating a technique that can arrange atoms at distances a mere 50 nanometers apart – a scale comparable to the width of a virus. The key to this breakthrough lies in the clever manipulation of laser light and atomic spins.
The team, led by Wolfgang Ketterle, the John D. MacArthur Professor of Physics at MIT, utilized dysprosium, the most magnetic atom in nature, for their experiments. They employed two laser beams with distinct frequencies and polarizations, which interacted with the super-cooled dysprosium atoms. This interaction resulted in two groups of atoms with opposite spins, each attracted to a specific laser beam.
The real ingenuity lay in creating standing waves of these laser beams. By overlaying the two standing waves and meticulously adjusting the frequencies, the researchers achieved peaks of laser intensity separated by only 50 nanometers. The dysprosium atoms, attracted to these peaks, ended up at this unprecedented proximity.
The experiment required exceptional stability of the laser beams, achieved by passing them through an optical fiber. This ensured that even with external disturbances, the relative positions of the beams remained unchanged, allowing for precise control over atomic positioning.
The team observed remarkable consequences of bringing dysprosium atoms so close. The magnetic forces, typically weak at larger distances, became a thousandfold stronger. This enhancement led to two previously unobserved phenomena: “thermalization”, where heat is transferred between the atom layers through magnetic fluctuations, and synchronized oscillations, where vibrations in one layer induced synchronous vibrations in the other.
The implications of this discovery are far-reaching. It provides a new tool for manipulating atoms, applicable to a wide range of elements, and opens up avenues for exploring uncharted territories in quantum phenomena. The researchers are particularly interested in using this technique to create configurations that could lead to the first purely magnetic quantum gate, a fundamental building block for a new type of quantum computer.
We are really bringing super-resolution methods to the field, and it will become a general tool for doing quantum simulations,
Ketterle states. “There are many variants possible, which we are working on.”
The team’s findings, published in the journal Science, mark a significant leap forward in the quest to control and understand the quantum world. The ability to position atoms at such close proximity paves the way for the creation of new quantum materials and the development of novel quantum technologies.
Link to the article: https://www.science.org/doi/10.1126/science.adh2712
Link to the original research story at MIT Research News.
The image is courtesy of MIT News.
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