Ultimate on-chip quantum amplifier.
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.
Astafiev
O V
OV
NEC Nano Electronics Research Laboratories, Tsukuba, Ibaraki 305-8501, Japan.
Abdumalikov
A A
AA
Zagoskin
A M
AM
Pashkin
Yu A
YA
Nakamura
Y
Y
Tsai
J S
JS