Clouds of supercooled atoms offer highly sensitive rotation sensors and tests of quantum mechanics.
A new device that relies on cloud flow of ultra-cold atoms promises potential evidence of the intersection between the rarity of the quantum world and the familiarity of the macroscopic world that we experience every day. The Atomictronic Superconducting Quantum Interference Device (SQUID) is also potentially useful for ultrasensitive rotation measurements and as a component in quantum computers.
“In a conventional SQUID, quantum interference in electron currents can be used to make one of the most sensitive magnetic field detectors,” said Changhyun Ryu, a physicist at the Quantum Group of Materials and Applications Physics at the Los Angeles National Laboratory. Alamos. “We use neutral atoms instead of charged electrons. Rather than responding to magnetic fields, the atomtronic version of a SQUID is sensitive to mechanical rotation. “
A schematic of an atomtronic SQUID shows semicircular traps that separate clouds of atoms, which quantum mechanically interfere when the device is rotated. Credit: Los Alamos National Laboratory
Although small, only about ten millionths of a meter in diameter, the Atomic SQUID is thousands of times larger than the molecules and atoms that are generally governed by the laws of quantum mechanics. The device’s relatively large scale allows it to test macroscopic realism theories, which could help explain how the world we are familiar with supports the quantum weirdness that rules the universe on very small scales. At a more pragmatic level, atomtronic SQUIDs could offer highly sensitive rotation sensors or perform calculations as part of quantum computers.
The researchers created the device by trapping cold atoms in a sheet of laser light. A second laser that crosses the “painted” patterns on the sheet that guided the atoms into two semicircles separated by small spaces known as Josephson Junctions.
When the SQUID is rotated and the Josephson junctions move toward each other, the populations of atoms in the semicircles change as a result of the quantum mechanical interference of currents through the Josephson junctions. By counting the atoms in each section of the semicircle, researchers can very precisely determine the rotation speed of the system.
As the first prototype STRID atomtronic, the device has a long way to go before it can lead to new guidance systems or ideas about the connection between the quantum and classical worlds. The researchers hope that expanding the device to produce larger diameter atomtronic SQUIDs could open the door to practical applications and new ideas in quantum mechanics.
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Reference: “Quantum interference of currents in an atomtronic BALL” by C. Ryu, EC Samson and MG Boshier, July 3, 2020, Nature’s Communications.
DOI: 10.1038 / s41467-020-17185-6
The Research and Development program led by the Los Alamos National Laboratory provided funds.
