As can be seen at once, in contrast to the coherent state the quantum noise is not independent of the phase of the light wave anymore.
Henry returned to the physics of quantum noise in 1996.
Therefore one can interpret the quantum noise of a coherent state as being due to the vacuum fluctuations.
These receivers are so sensitive that an accurate description of the device performance must take into account the effects of quantum noise.
Put a narrow laser beam in the center of one of the calcium absorption lines" In the study they were talking about quantum noise.
The uncertainty principle sets the lower bound of quantum noise in an amplifier.
In the case of number of particles (photons or electrons), the quantum noise is also called shot noise.
In this case, the quantum noise appears as shot noise only.
Generally, quantum noise can be considered as error of description of any physical system within classical (not quantum) theory.
In an electric circuit, the random fluctuations of a signal due to discrete character of electrons can be called quantum noise.
