First Atomtronic Radio Broadcasts Matter Waves

Arxiv – A Matterwave Transistor Oscillator

A triple-well atomtronic transistor combined with forced RF evaporation is used to realize a driven matterwave oscillator circuit. The transistor is implemented using a metalized compound glass and silicon substrate. On-chip and external currents produce a cigar-shaped magnetic trap, which is divided into transistor source, gate, and drain regions by a pair of blue-detuned optical barriers projected onto the magnetic trap through a chip window. A resonant laser beam illuminating the drain portion of the atomtronic transistor couples atoms emitted by the gate to the vacuum. The circuit operates by loading the source with cold atoms and utilizing forced evaporation as a power supply that produces a positive chemical potential in the source, which subsequently drives oscillation.

Oscillating circuits are the workhorses of many electronic devices. In particular, oscillating electrons emit electromagnetic waves, a mechanism that has lead to one or two applications that readers may have come across.

Seth Caliga and teams at the University of Colorado and National Institute for Standards and Technology in Boulder have built a version of this kind of circuit that works with atoms rather than electrons.

Their atomtronic circuit generates an oscillating atom current that emits matter waves in which atoms carry energy through space.

The heart of their device is an atomtronic transistor–an optomagnetic trap with three compartments that can hold a Bose Einstein Condensate of rubidium atoms cooled almost to absolute zero.

We presume that the earliest driven oscillators were mechanical clocks, such as the grandfather clock that utilizes gravitational energy to sustain oscillation of a pendulum. Its operation, too, can be cast in terms of gain, feedback, frequency selective elements and a power supply. As sources of electromagnetic waves, driven oscillators of many types have left a noble legacy of technology and scientifi c advancement, beginning with the early days of radio. The matterwave oscillator may likewise have a signifi cant role to play in the development of atom-based sensors, and perhaps in quantum information processing as well.

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