296 research outputs found

    Fock representation of the renormalized higher powers of white noise and the Virasoro--Zamolodchikov--ww_{\infty} *--Lie algebra

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    The identification of the *--Lie algebra of the renormalized higher powers of white noise (RHPWN) and the analytic continuation of the second quantized Virasoro--Zamolodchikov--ww_{\infty} *--Lie algebra of conformal field theory and high-energy physics, was recently established in \cite{id} based on results obtained in [1] and [2]. In the present paper we show how the RHPWN Fock kernels must be truncated in order to be positive definite and we obtain a Fock representation of the two algebras. We show that the truncated renormalized higher powers of white noise (TRHPWN) Fock spaces of order 2\geq 2 host the continuous binomial and beta processes

    Random variables and positive definite Kernels associates with the Schrodinger algebra

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    We show that the Feinsilver‐Kocik‐Schott (FKS) kernel for the Schrödinger algebra is not positive definite. We show how the FKS Schrödinger kernel can be reduced to a positive definite one through a restriction of the defining parameters of the exponential vectors. We define the Fock space associated with the reduced FKS Schrödinger kernel. We compute the characteristic functions of quantum random variables naturally associated with the FKS Schrödinger kernel and expressed in terms of the renormalized higher powers of white noise (or RHPWN) Lie algebra generators

    The Centrally extended Heisenberg algebra and its connection with Schrodinger, Galilei and renormalized higher powers of quantum white noise Lie algebra

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    In previous papers we have shown that the one mode Heisenberg algebra Heis(1) admits a unique non-trivial central extensions CeHeis(1) which can be realized as a sub-Lie-algebra of the Schrödinger algebra, in fact the Galilei Lie algebra. This gives a natural family of unitary representations of CeHeis(1) and allows an explicit determination of the associated group by exponentiation. In contrast with Heis(1), the group law for CeHeis(1) is given by nonlinear (quadratic) functions of the coordinates. The vacuum characteristic and moment generating functions of the classical random variables canonically associated to CeHeis(1) are computed. The second quantization of CeHeis(1) is also considered

    Unitarity conditions for stochastic differential equations driven by nonlinear quantum noise

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    We prove the stochastic independence of the basic integrators of the renormalized square of white noise (SWN). We use this result to deduce the unitarity conditions for stochastic differential equations driven by the SWN

    Unitarity conditions for the renormalized square of white noise

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    The formal unitarity conditions for stochastic equations driven by the renormalized square of white noise are shown to hold rigorously in the framework of sesquilinear forms on the Fock space

    On the Fock representation of the renormalized powers of quantum white noise

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    We describe the "no-go" theorems recently obtained by Accardi-Boukas-Franz in [\cite{1}] for the Boson case, and by Accardi-Boukas in [\cite{2}] for the qq-deformed case, on the issue of the existence of a common Fock space representation of the renormalized powers of quantum white noise (RPWN)

    Renormalized powers of quantum white noise

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    We prove some no-go theorems on the existence of a Fock representation of the *-Lie algebra. In particular we prove the nonexistence of such a representation for any *-Lie algebra containing . This drastic difference with the quadratic case proves the necessity of investigating different renormalization rules for the case of higher powers of white noise

    Control of quantum stochastic differential equations

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    We review the basic features of the quantum stochastic calculus. Iteration schemes for the computation of the matrix elements of solutions of unitary quantum stochastic evolutions and associated quantum flows are provided along with a basic error analysis of the convergence of the iteration schemes. The application of quantum stochastic calculus to the solution of the quantum version of the quadratic cost control problem is described

    Towards reviving post-Olympic Athens as a cultural destination

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    This paper examines the effects of global change on the status and qualities of the Greek national capital, Athens, focusing on how they affect the development of cultural tourism in the city. Although Athens constituted one of the most significant destinations for Greek tourism in the past, in recent years it started to weaken. Athens is characterised by a series of problems, among them are the degradation of its environment and quality of life and traffic congestion. However, in terms of tourism development, the Olympic Games helped in re-imaging the city and upgrading its infrastructure. This study based on semi-structured interviews with top officials reveals how global change has affected Athens’ socio-cultural/economic status, identity and image. Despite the tourism policy/planning responses to global changes, Athens’ tourism continues to decline leaving unexplored potential such as its rich cultural heritage, new multicultural identity and the New Acropolis Museum. The paper suggests that cultural elements of capital cities must be multidimensional including a variety of attractions and amenities. The use of cultural heritage assets needs to be in line with global developments in order for cities to effectively leverage heritage for cultural tourism
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