A dynamical point of view of Quantum Information: Wigner measures

We analyze a known version of the discrete Wigner function and some connections with Quantum Iterated Funcion Systems. This paper is a follow up of "A dynamical point of view of Quantum Information: entropy and pressure" by the same authors

Site recurrence of open and unitary quantum walks on the line

We study the problem of site recurrence of discrete time nearest neighbor open quantum random walks (OQWs) on the integer line, proving basic properties and some of its relations with the corresponding problem for unitary (coined) quantum walks (UQWs). For both kinds of walks our discussion concerns two notions of recurrence, one given by a monitoring procedure, another in terms of P\'olya numbers, and we study their similarities and differences. In particular, by considering UQWs and OQWs induced by the same pair of matrices, we discuss the fact that recurrence of these walks are related by an additive interference term in a simple way. Based on a previous result of positive recurrence we describe an open quantum version of Kac's lemma for the expected return time to a site

Fitzpatrick, Sheila. El equipo de Stalin. Los años más peligrosos de la Rusia soviética, De Lenin a Jrushov; Ed. Crítica; Barcelona; 2016

A una centuria de la Revolución Rusa, Fitzpatick propone un nuevo abordaje para analizar y comprender una de sus etapas más relevantes: el estalinismo. La autora, profesora de las Universidades de Sídney (Australia) y Chicago (Estados Unidos), es una especialista en el tema y una de las voces autorizadas dentro de la historiografía basada en los estudios de la historia soviética, siendo La revolución Rusa una de sus obras de mayor relevancia.Universidad Nacional de Rosari

A dynamical point of view of Quantum Information: entropy and pressure

Quantum Information is a new area of research which has been growing rapidly since last decade. This topic is very close to potential applications to the so called Quantum Computer. In our point of view it makes sense to develop a more "dynamical point of view" of this theory. We want to consider the concepts of entropy and pressure for "stationary systems" acting on density matrices which generalize the usual ones in Ergodic Theory (in the sense of the Thermodynamic Formalism of R. Bowen, Y. Sinai and D. Ruelle). We consider the operator $\mathcal{L}$ acting on density matrices $\rho\in \mathcal{M}_N$ over a finite $N$-dimensional complex Hilbert space $\mathcal{L}(\rho):=\sum_{i=1}^k tr(W_i\rho W_i^*)V_i\rho V_i^*,$ where $W_i$ and $V_i$, $i=1,2,...k$ are operators in this Hilbert space. $\mathcal{L}$ is not a linear operator. In some sense this operator is a version of an Iterated Function System (IFS). Namely, the $V_i\,(.)\,V_i^*=:F_i(.)$, $i=1,2,...,k$, play the role of the inverse branches (acting on the configuration space of density matrices $\rho$) and the $W_i$ play the role of the weights one can consider on the IFS. We suppose that for all $\rho$ we have that $\sum_{i=1}^k tr(W_i\rho W_i^*)=1$. A family $W:=\{W_i\}_{i=1,..., k}$ determines a Quantum Iterated Function System (QIFS) $\mathcal{F}_{W}$, $\mathcal{F}_W=\{\mathcal{M}_N,F_i,W_i\}_{i=1,..., k}.

Bioactivity of Azadirachta Excelsa Jack. Extractives on Selected Insects

Azadirachta excelsa Jack. is a fast growing timber species that has been newly chosen as a potential forest plantation species to overcome timber deficit for domestic consumption in future. This species like Azadirachta indica is suspected to contain biologically active compounds that is detrimental on insects. Many studies have been done on the A. indica, a relative species to A. excelsa, however, studies on A. excelsa are still in preliminary stages. Therefore, the aim of this study was to evaluate the effect of A.excelsa crude extractives towards three selected insect pests, (i.e. Spodoptera Iitura, Callosobruchus chinensis and Coptotermes curvignathus). A preliminary test to evaluate the susceptibility of A. excelsa wood towards termites, compared to Koompasia malaccensis, Hevea brasiliensis and Pinus caribaea was also conducted. In the first part of the study, the A.excelsa plant extracts were extracted from different plant parts (i.e. leaf, bark, trunk, twigs and branch) using a range of polar to non-polar solvents, namely hexane, petroleum ether, toluene, ethyl acetate and methanol. The plant extractives were sampled and analysed through Thin Layer Chromatography (TLC) and Infrared Spectrocopy (IR). In the second part of the study, bioassay tests were conducted on the selected insects. The insects were exposed to the plant extractives prepared at three concentration levels (i.e. 250 ppm, 500 ppm and 1000 ppm) and the solvents (0 ppm) as the control, by feeding the insects with treated food source. The S. litura larvae were fed with castor leaf discs soaked in the respective extractives. The C. chinensis adults were exposed to mungbean seeds that had been soaked in the plant extrctives while the C. curvignathus were fed with treated filter paper. In the last part of this study, the A. excelsa wood together with the other three wood species mentioned earlier, were exposed to the termites both in the laboratory and field

A Thermodynamic Formalism for density matrices in Quantum Information

We consider new concepts of entropy and pressure for stationary systems acting on density matrices which generalize the usual ones in Ergodic Theory. Part of our work is to justify why the definitions and results we describe here are natural generalizations of the classical concepts of Thermodynamic Formalism (in the sense of R. Bowen, Y. Sinai and D. Ruelle). It is well-known that the concept of density operator should replace the concept of measure for the cases in which we consider a quantum formalism. We consider the operator $\Lambda$ acting on the space of density matrices $\mathcal{M}_N$ over a finite $N$-dimensional complex Hilbert space $$\Lambda(\rho):=\sum_{i=1}^k tr(W_i\rho W_i^*)\frac{V_i\rho V_i^*}{tr(V_i\rho V_i^*)},$$ where $W_i$ and $V_i$, $i=1,2,..., k$ are linear operators in this Hilbert space. In some sense this operator is a version of an Iterated Function System (IFS). Namely, the $V_i\,(.)\,V_i^*=:F_i(.)$, $i=1,2,...,k$, play the role of the inverse branches (i.e., the dynamics on the configuration space of density matrices) and the $W_i$ play the role of the weights one can consider on the IFS. In this way a family $W:=\{W_i\}_{i=1,..., k}$ determines a Quantum Iterated Function System (QIFS). We also present some estimates related to the Holevo bound