The Perception of Facial Profile in Korean

Origin of quantum noise and decoherence in distributed amplifiers

“…The entanglement with the environment and the associated decoherence can be avoided in a phasesensitive amplifier. This has been discussed previously [2,3,5,8,[12][13][14]16,[28][29][30][31] and an analysis of phasesensitive amplifiers is beyond the intended scope of this paper. Roughly speaking, the entanglement with the environment could be avoided in this model if the amplifying atoms were in a coherent superposition of their ground and excited states with a definite relative phase.…”

“…The approach described here includes the entanglement between the signal and the environment in a transparent way that can be readily applied to the case of Schrodinger cat states. Prior studies of decoherence of Schrodinger cat states [1][2][3][4][5] did not include the important case of a distributed amplifier. The results presented here can be used to analyze many systems of potential practical importance, including the effects of a distributed amplifier on long-range nonlocal interferometry using superpositions of macroscopic states [25,27].…”

“…The transmission of quantum information over large distances in optical fibers is limited by the effects of loss and decoherence. It has previously been suggested that the use of distributed amplifiers may have some potential benefits in reducing the rate of decoherence [1][2][3][4][5]. Roughly speaking, noise that is introduced by amplification in one part of the fiber will be attenuated by loss in subsequent parts of the fiber.…”

“…The quantum noise produced by an optical amplifier has been investigated since the earliest days of quantum optics [6][7][8][9][10][11]. Most of those calculations were based on the introduction of a noise operator as required by unitarity [4,6,8] or on the master equation and related techniques [2,10,11]. For a linear amplifier, this results in a quantum noise that is added to the signal, and calculations of that kind characterize the statistical properties of the added noise.…”