On the other hand, F > 1 and F < 1 correspond to electron bunching or anti-bunching, respectively.
Recent theory predicts an interesting phenomenon; the electron transport through the quantum dot in the Kondo regime exhibits the electron bunching, that is, two electrons are simultaneously scattered because of the Kondo correlation at the quantum dot.
The amplitude of the forward growing wave drops at the sever location; however, the wave starts growing again after the sever, attributed to the modulation carried forward by the electron bunching
. The challenge for a sever design is to attenuate the forward wave over a wide range of frequencies and at the same time not letting the reflections to build up in the circuit.
A) Cyclotron Resonance Masers: In CRMs, the main effect leading to electron bunching
and to coherent bremsstrahlung radiation is the relativistic dependence of electron cyclotron frequency on its energy.