23,555 research outputs found

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

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    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 L\mathcal{L} acting on density matrices ρMN\rho\in \mathcal{M}_N over a finite NN-dimensional complex Hilbert space L(ρ):=i=1ktr(WiρWi)ViρVi,\mathcal{L}(\rho):=\sum_{i=1}^k tr(W_i\rho W_i^*)V_i\rho V_i^*, where WiW_i and ViV_i, i=1,2,...ki=1,2,...k are operators in this Hilbert space. L\mathcal{L} is not a linear operator. In some sense this operator is a version of an Iterated Function System (IFS). Namely, the Vi(.)Vi=:Fi(.)V_i\,(.)\,V_i^*=:F_i(.), i=1,2,...,ki=1,2,...,k, play the role of the inverse branches (acting on the configuration space of density matrices ρ\rho) and the WiW_i play the role of the weights one can consider on the IFS. We suppose that for all ρ\rho we have that i=1ktr(WiρWi)=1\sum_{i=1}^k tr(W_i\rho W_i^*)=1. A family W:={Wi}i=1,...,kW:=\{W_i\}_{i=1,..., k} determines a Quantum Iterated Function System (QIFS) FW\mathcal{F}_{W}, $\mathcal{F}_W=\{\mathcal{M}_N,F_i,W_i\}_{i=1,..., k}.

    A dynamical point of view of Quantum Information: Wigner measures

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    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

    A Thermodynamic Formalism for density matrices in Quantum Information

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    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 Λ\Lambda acting on the space of density matrices MN\mathcal{M}_N over a finite NN-dimensional complex Hilbert space Λ(ρ):=i=1ktr(WiρWi)ViρVitr(ViρVi), \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 WiW_i and ViV_i, i=1,2,...,ki=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 Vi(.)Vi=:Fi(.)V_i\,(.)\,V_i^*=:F_i(.), i=1,2,...,ki=1,2,...,k, play the role of the inverse branches (i.e., the dynamics on the configuration space of density matrices) and the WiW_i play the role of the weights one can consider on the IFS. In this way a family W:={Wi}i=1,...,kW:=\{W_i\}_{i=1,..., k} determines a Quantum Iterated Function System (QIFS). We also present some estimates related to the Holevo bound

    Diagnóstico de Ralstonia solanacearum em tomateiro.

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    Pretende-se, com esta publicação, fornecer informações sobre os processos envolvidos na identificação da doença, coleta e envio de material para análise laboratorial, técnicas de identificação e armazenamento de cepas do patógeno.bitstream/item/84927/1/cot-92.pd

    Amostragem de sementes para análise em laboratório.

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