Abstract
We report amplification of electromagnetic waves by a single artificial atom in open 1D space. Our three-level artificial atom—a superconducting quantum circuit—coupled to a transmission line presents an analog of a natural atom in open space. The system is the most fundamental quantum amplifier whose gain is limited by a spontaneous emission mechanism. The noise performance is determined by the quantum noise revealed in the spectrum of spontaneous emission, also characterized in our experiments.
- Received 14 January 2010
DOI:https://doi.org/10.1103/PhysRevLett.104.183603
©2010 American Physical Society