N ov 2 00 4 Signal Transmission in Passive Media
نویسنده
چکیده
Abstract: Under rather general assumptions, and in a relatively simple and straightforward manner, it is shown that the characteristics of signals which travel through homogeneous, as well as inhomogeneous, passive media have the principal features usually associated with the phenomena of precursors, as generally follows from more elaborate studies. The simplicity of the present arguments permit analytic studies to be made for a greater variety of media than is normally the case. Under rather general assumptions, and in a relatively simple and straightforward manner, it is shown that the characteristics of signals which travel through homogeneous, as well as inhomogeneous, passive media have the principal features usually associated with the phenomena of precursors, as generally follows from more elaborate studies. The simplicity of the present arguments permit analytic studies to be made for a greater variety of media than is normally the case.
منابع مشابه
ar X iv : q ua nt - p h / 03 11 00 6 v 1 3 N ov 2 00 3 Continuous - variable quantum cryptography is secure against non - gaussian attacks
A general study of arbitrary finite-size coherent attacks against continuous-variable quantum cryptographic schemes is presented. It is shown that, if the size of the blocks that can be coherently attacked by an eavesdropper is fixed and much smaller than the key size, then the optimal attack for a given signal-to-noise ratio in the transmission line is an individual gaussian attack. Consequent...
متن کاملN ov 2 00 4 Inhomogeneous Anisotropic Passive Scalars
We investigate the behaviour of the two-point correlation function in the context of passive scalars for non homogeneous, non isotropic forcing ensembles. Exact analytical computations can be carried out in the framework of the Kraichnan model for each anisotropic sector. We will focus our attention on the isotropic sector with isotropic forcing in order to obtain a description of the influence...
متن کاملar X iv : q ua nt - p h / 01 10 17 0 v 2 9 N ov 2 00 2 Photon number conservation and photon interference
The group theoretical aspect of the description of passive lossless optical four-ports (beam splitters) is revisited. It is shown through an example, that this approach can be useful in understanding interferometric schemes where a low number of photons interfere. The formalism is extended to passive lossless optical six-ports, their SU(3)-theory is outlined.
متن کاملN ov 2 00 4 On entropic quantities related to the classical capacity of infinite dimensional quantum channels
متن کامل
N ov 2 00 4 February 1 , 2008 DIRAC - HARMONIC MAPS
We introduce a functional that couples the nonlinear sigma model with a spinor field: L = ∫ M [|dφ|2 + (ψ,D/ψ)]. In two dimensions, it is conformally invariant. The critical points of this functional are called Dirac-harmonic maps. We study some geometric and analytic aspects of such maps, in particular a removable singularity theorem.
متن کامل