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A generalization of the conservation integral

Volkmar Liebscher (1998)

Banach Center Publications

Starting from the scheme given by Hudson and Parthasarathy [7,11] we extend the conservation integral to the case where the underlying operator does not commute with the time observable. It turns out that there exist two extensions, a left and a right conservation integral. Moreover, Itô's formula demands for a third integral with two integrators. Only the left integral shows similar continuity properties to that derived in [11] used for extending the integral to more than simple integrands. In...

A noncommutative limit theorem for homogeneous correlations

Romuald Lenczewski (1998)

Studia Mathematica

We state and prove a noncommutative limit theorem for correlations which are homogeneous with respect to order-preserving injections. The most interesting examples of central limit theorems in quantum probability (for commuting, anticommuting, and free independence and also various q-qclt's), as well as the limit theorems for the Poisson law and the free Poisson law are special cases of the theorem. In particular, the theorem contains the q-central limit theorem for non-identically distributed variables,...

Asymptotic spectral analysis of growing graphs: odd graphs and spidernets

Daisuke Igarashi, Nobuaki Obata (2006)

Banach Center Publications

Two new examples are given for illustrating the method of quantum decomposition in the asymptotic spectral analysis for a growing family of graphs. The odd graphs form a growing family of distance-regular graphs and the two-sided Rayleigh distribution appears in the limit of vacuum spectral distribution of the adjacency matrix. For a spidernet as well as for a growing family of spidernets the vacuum distribution of the adjacency matrix is the free Meixner law. These distributions are calculated...

Asymptotic spectral distributions of distance-k graphs of Cartesian product graphs

Yuji Hibino, Hun Hee Lee, Nobuaki Obata (2013)

Colloquium Mathematicae

Let G be a finite connected graph on two or more vertices, and G [ N , k ] the distance-k graph of the N-fold Cartesian power of G. For a fixed k ≥ 1, we obtain explicitly the large N limit of the spectral distribution (the eigenvalue distribution of the adjacency matrix) of G [ N , k ] . The limit distribution is described in terms of the Hermite polynomials. The proof is based on asymptotic combinatorics along with quantum probability theory.

Chaotic decompositions in 2 -graded quantum stochastic calculus

Timothy Eyre (1998)

Banach Center Publications

A brief introduction to 2 -graded quantum stochastic calculus is given. By inducing a superalgebraic structure on the space of iterated integrals and using the heuristic classical relation df(Λ) = f(Λ + dΛ) - f(Λ) we provide an explicit formula for chaotic expansions of polynomials of the integrator processes of 2 -graded quantum stochastic calculus.

Characterization of unitary processes with independent and stationary increments

Lingaraj Sahu, Kalyan B. Sinha (2010)

Annales de l'I.H.P. Probabilités et statistiques

This is a continuation of the earlier work (Publ. Res. Inst. Math. Sci.45 (2009) 745–785) to characterize unitary stationary independent increment gaussian processes. The earlier assumption of uniform continuity is replaced by weak continuity and with technical assumptions on the domain of the generator, unitary equivalence of the process to the solution of an appropriate Hudson–Parthasarathy equation is proved.

Decompositions of Beurling type for E₀-semigroups

Rolf Gohm (2006)

Banach Center Publications

We define tensor product decompositions of E₀-semigroups with a structure analogous to a classical theorem of Beurling. Such decompositions can be characterized by adaptedness and exactness of unitary cocycles. For CCR-flows we show that such cocycles are convergent.

Explicit construction of a unitary double product integral

R. L. Hudson, Paul Jones (2011)

Banach Center Publications

In analogy with earlier work on the forward-backward case, we consider an explicit construction of the forward-forward double stochastic product integral ( 1 + d r ) with generator d r = λ ( d A d A - d A d A ) . The method of construction is to approximate the product integral by a discrete double product ( j , k ) m × Γ ( R m , n ( j , k ) ) = Γ ( ( j , k ) m × ( R m , n ( j , k ) ) ) of second quantised rotations R m , n ( j , k ) in different planes using the embedding of m into L²(ℝ) ⊕ L²(ℝ) in which the standard orthonormal bases of m and ℂⁿ are mapped to the orthonormal sets consisting of normalised indicator functions of...

Feynman diagrams and the quantum stochastic calculus

John Gough (2006)

Banach Center Publications

We present quantum stochastic calculus in terms of diagrams taking weights in the algebra of observables of some quantum system. In particular, we note the absence of non-time-consecutive Goldstone diagrams. We review recent results in Markovian limits in these terms.

Hall's transformation via quantum stochastic calculus

Paula Cohen, Robin Hudson, K. Parthasarathy, Sylvia Pulmannová (1998)

Banach Center Publications

It is well known that Hall's transformation factorizes into a composition of two isometric maps to and from a certain completion of the dual of the universal enveloping algebra of the Lie algebra of the initial Lie group. In this paper this fact will be demonstrated by exhibiting each of the maps in turn as the composition of two isometries. For the first map we use classical stochastic calculus, and in particular a stochastic analogue of the Dyson perturbation expansion. For the second map we make...

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