%0 Journal Article
%T Notes on the Essential System to Acquire Information
%A Paolo Rocchi
%J Advances in Mathematical Physics
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/480421
%X This paper introduces a short survey on recent information theories and reviews some critical notes expressed on quantum information. The severe difficulties emerging from the literature lead us to argue about the way to follow, and in a preliminary stage, we consider how to proceed in order to provide a reasonable contribution to the conceptualization of information in classical and quantum physics. We conclude that we should go toward the essential elements of the system that acquire information and should define the common components of the measurement processes. In this way we should be able to establish fundamental properties and to circumvent tricky difficulties arisen by the concept of the observer and the variety of interferences that disturb the acquisition of information. Universal experience shows how sharpness is the indispensable feature of detected signals and we calculate the discernability of observables using various mathematical formalisms. The present logical frame brings evidence on how information is not an absolute quantity, and we close with a few notes on the information relativism which modern literature tackles from the operational stance and the philosophical stance. 1. Introduction In 1982, Richard Feymann put forward the early concept of quantum computing and inaugurated quantum information science (QIS) which is a mixture of physics, computing and engineering. Basically, QIS is grounded upon Shannon¡¯s seminal work [1], and Von Neumann introduced the analog of the information entropy in the quantum context where is the density operator. If is eigenvalue of with associate eigenvector , we have where ¡¯s are orthonormal. The density operator in (1.2) corresponds to a set of quantum states with probability Later the quantum analogue of Shannon¡¯s noiseless coding theorem was developed by Schumacher [2]. Ample debate arose about the limits of this conceptual framework. In fact, the everyday concept of information is closely associated with the concepts of knowledge and meaning, and it is reliant on the prior concept of the observer: all of them cause pressing and endemic problems. Shannon¡¯s deliberate exclusion of semantic aspects from his theory fired criticism [3] and led a number of authors to elaborate alternative information theories. The following partial list of proposed theories can give an idea of the strong opposition to Shannon interpretation as universal interpretation of information: (i)semantic theory of information by Carnap [4],(ii)logical theory of information by Tarski [5],(iii)cybernetic information theory by
%U http://www.hindawi.com/journals/amp/2010/480421/