Coherent Matterwave Emission from an Atomtronic Transistor Oscillator
Atomtronics is the atom dual of electronics in which atom flux substitute for electric current and chemical potential substitutes for electric potential. Among the most ubiquitous electronic components is the semiconductor transistor; it is ubiquitous because it provides gain, and gain enables amplifiers, oscillators, switches, logic, etcetera, providing functionality as complex as radios and smart phones. The transistor’s critical role in classical information processing leads us to consider analogs in the ultracold atom domain where quantum characteristics can dominate circuit behavior. This work presents experimental and theoretical studies of an atom analog of the transistor consisting of a triple-well atomic potential produced with a hybrid system of magnetic and optical potentials. The transistor consists of three wells: a broad “source” well, a narrow “gate” well, and a broad “drain” well. The wells are separated by two narrow potential barriers. We operate an atomtronic transistor circuit by preparing atoms in the source well as a Bose-Einstein condensate having very low temperature. Here “very low” means that the atomic thermal energy is on the order and less than the gate well energy level spacing and also the characteristic tunneling energies of the barriers. The gate well is nearly parabolic and can thus be treated as a harmonic oscillator. In this low temperature regime, the circuit operates in a manner much like a transistor oscillator and it emits a coherent matterwave. A many-body treatment of the gate well is combined with an equivalent circuit model of the transistor circuit to derive steady-state behavior.
Host: Charles Clark