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A Matterwave Transistor Oscillator

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The atomtronic transistor

Seth C. Caliga, Cameron J. E. Straatsma, Alex A. Zozulya, Dana Z. Anderson
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. High-resolution in-trap absorption imagery reveals gate atoms that have tunneled from the source and establishes that the circuit emits a nominally mono-energetic matterwave with a frequency of 23.5(1.0) kHz by tunneling from the gate, corresponding to a vacuum energy of 2.67 MHz x h, where h is Planck’s constant, and a vacuum wavelength of 29 nm. Time-of-flight measurements indicate that the transistor exhibits ohmic cooling, i.e. negative resistance, and therefore has gain. Time-of-flight measurements are also used to determine an upper bound of the atomtronic transresistance, r<0.01 Hz/Hz x h/m^2 where m is the mass of rubidium 87, and that the closed-loop circuit energy gain varies between 3.1 and 3.6.
Read more: http://arxiv.org/pdf/1208.3109v1.pdf

Read also: First Atomtronic Radio Broadcasts Matter Waves

Written by physicsgg

August 20, 2012 at 3:20 pm

Posted in ATOMIC PHYSICS

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