Quantum Physics

A newly discovered phenomenon renders atoms visible to specific light frequencies.

“Collectively induced transparency” (CIT) is a new phenomenon that causes groups of atoms to suddenly stop reflecting light at specific frequencies.

By laser-blasting ytterbium atoms inside an optical cavity, which is essentially a small box for light, CIT was discovered. As the frequency of the light is changed, a transparency window appears in which the light simply passes through the cavity unimpeded, despite the fact that the laser’s light will initially bounce off the atoms.

“We never knew this straightforwardness window existed,” says Caltech’s Andrei Faraon (BS ’04), William L. Valentine Teacher of Applied Physical Science and Electrical Designing, and co-creator of a paper on the revelation that was distributed on April 26 in the journal Nature. “Our research has primarily evolved into an exploration of the reason.

“Through conventional quantum optics measurement techniques, we discovered that our system had entered an unexplored regime, revealing new physics,”

Rikuto Fukumori, co-lead author of the paper.

The transparency window appears to be the result of atom-light interactions in the cavity, according to analysis. Destructive interference, in which waves from two or more sources cancel each other out, is similar to this phenomenon. The gatherings of iotas persistently assimilate and once again produce light, which by and large results in the impression of the laser’s light. However, there is a drop in reflection at the CIT frequency due to the re-emitted light from each group atom creating a balance.

According to co-lead author Mi Lei, a graduate student at Caltech, “an ensemble of atoms strongly coupled to the same optical field can lead to unexpected results.”

The optical resonator, which is estimated to be only 20 microns long and incorporates highlights less than 1 micron, was created at the Kavli Nanoscience Organization at Caltech.

Rikuto Fukumori, a graduate student and co-lead author of the paper, states, “Through conventional quantum optics measurement techniques, we found that our system had reached an unexplored regime, revealing new physics.”

Other than the straightforwardness peculiarity, the specialists likewise saw that the assortment of particles can ingest and produce light from the laser either a lot quicker or a lot more slowly compared with a solitary iota relying upon the power of the laser. Due to the large number of interacting quantum particles, these processes—superradiance and subradiance—and their underlying physics remain poorly understood.

Co-corresponding author Joonhee Choi, a former postdoctoral scholar at Caltech who is now an assistant professor at Stanford University, states, “We were able to monitor and control quantum mechanical light-matter interactions at the nanoscale.”

This discovery has the potential to one day help pave the way for more efficient quantum memories in which information is stored in an ensemble of strongly coupled atoms, despite the fact that the research is primarily fundamental and expands our understanding of the mysterious world of quantum effects. Faraon has likewise dealt with quantum stockpiling by controlling the connections between different vanadium molecules.

Manuel Endres, a professor of physics and Rosenberg Scholar who is a co-author of the study, states, “In addition to memories, these experimental systems provide important insight about developing future connections between quantum computers.” Endres is also a co-author of the study.

More information: Mi Lei et al, Many-body cavity quantum electrodynamics with driven inhomogeneous emitters, Nature (2023). DOI: 10.1038/s41586-023-05884-1

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