Researchers from Joint Institute for Laboratory Astrophysics isolated groups of a few atoms to measure their multi-particle interactions within an atomic clock
A team of researchers from Joint Institute for Laboratory Astrophysics (JILA) isolated groups of a few atoms and accurately measured their multi-particle interactions within an atomic clock. According to the researchers, the development is expected to facilitate control of interacting quantum matter. This in turn is expected to boost the performance of atomic clocks and quantum information systems. The findings offer the first quantitative evidence of events when a few fermions are packed together as these atoms cannot be in the same quantum state and location at the same time. The research was published in the journal on October 31, 2018.
The researchers used 3D strontium lattice clock that offers precise atom control. Arrays of isolated few-body systems in an optical clock based on a three-dimensional lattice of fermionic strontium atoms were created between one and five atoms per lattice cell. The team used a laser to start the clock and the laser also helped to switch at a specific frequency between two energy levels in the atoms. A new imaging technique for optical frequencies was used to measure the atoms’ quantum states. The team observed nonlinear or unpredicted results based on previous experiments when three or more atoms were together in a cell. The measurements were combined with theoretical predictions of another team at National Institute of Standards and Technology (NIST) to conclude that multi-particle interactions occurred.
The team observed that the clock’s frequency shifted in unexpected ways when three or more atoms were in a lattice site. According to the researchers, the shift varies from one resulting from summing up various pairs of atoms. As explained by NIST and JILA Fellow Jun Ye, five atoms per cell caused a shift of 20% compared to normally expected shift. The research was supported by NIST, the Defense Advanced Research Projects Agency, the Army Research Office, the Air Force Office of Scientific Research, National Science Foundation, and NASA.