Scientists have discovered an atom filled with atoms. The atom's electrons orbit at such a great distance that there's room for other atoms.

The atoms within the "giant atom" form weak bonds, producing a new exotic state of matter — what scientists have dubbed "Rydberg polarons."

The discovery combines a pair of atomic phenomenon, both of which can only be studied under extremely cold conditions: Bose-Einstein condensates and Rydberg atoms.

A Bose-Einstein condensate is a unique state of matter observed only at temperatures approaching absolute zero. Rydberg atoms are atoms featuring a single electron in a distant orbit and a highly excited state.

"The average distance between the electron and its nucleus can be as large as several hundred nanometers — that is more than a thousand times the radius of a hydrogen atom," Joachim Burgdörfer, a professor at the Vienna University of Technology in Austria, said in a news release.

As part of the latest experimentation — carried out with the help of scientists at Rice University in Houston — researchers created a Bose-Einstein condensate using strontium atoms. Scientists converted one of the condensate's atoms into a Rydberg atom using a laser.

The orbital radius of the atom's newly excited electron became much wider than the distance between the condensate's two atoms. As a result, the electron came to orbit, not only its original atomic nucleus, but multiple Bose-Einstein condensate atoms.

"The atoms do not carry any electric charge, therefore they only exert a minimal force on the electron," said researcher Shuhei Yoshida.

That minimal force is enough, however, to diminish the total energy of the giant atom and cause weak atomic bonds to form within the unusual atomic system.

"It is a highly unusual situation," said Yoshida. "Normally, we are dealing with charged nuclei, binding electrons around them. Here, we have an electron, binding neutral atoms."

Scientists described the newly named Rydberg polarons in the journal Physical Review Letters.

New technology powers record-fast optical distance measurement
Washington (UPI) Feb 26, 2018 –

Scientists in Europe have demonstrated the fastest optical distance measurement on record. The researchers used their new and improved LIDAR technology to measure a speeding bullet.

"We managed to sample the surface structure of the projectile on-the-fly, achieving micrometer accuracy," Christian Koos, a professor at Karlsruhe Institute of Technology in Germany, said in a news release. "To this end, we recorded 100 million distance values per second, corresponding to the fastest distance measurement so far demonstrated."

The new LIDAR system's 3D cameras are comprised of chip-based optical microresonators. The resonators are made from silicon nitride and produce a soliton frequency comb.

Frequency combs produce a spectrum of sharp, equally spaced frequency lines. The lines work like a ruler. The technology is used in a variety of fields, but is most often employed as a sensor capable of measuring the spectral properties of tiny targets.

The generation of frequency combs is typically an energy-intensive process, and the technology often takes up a lot of space. But scientists at the Swiss Federal Institute of Technology in Lausanne, EPFL, have developed a chip-scale light source capable of producing frequency combs.

The technology converts laser light into optical light pulses called dissipative Kerr solitons. The succession of pulses produces a full broadband optical spectrum. The chip-scale conversion process is made possible by silicon nitride microresonsators.

"We have developed low-loss optical resonators, in which extremely high optical intensities can be generated — a prerequisite for soliton frequency combs," said EPFL professor Tobias Kippenberg. "These so-called Kerr frequency combs have rapidly found their way into new applications over the previous years."

Scientists have previously used chip-scale frequency comb technology to create smaller, more versatile chemical sensors, as well as high-speed communications systems. Now, researchers have translated the technology for optical distance measurements.

The light source — detailed in the journal Science — could be used to improve satellite technology or the navigational abilities of autonomous drones.