scholarly journals A von Neumann type inequality for an annulus

2021 ◽  
pp. 125714
Author(s):  
Georgios Tsikalas
Keyword(s):  
Type Inequality ◽  
Von Neumann ◽  
Neumann Type

scholarly journals The Drury–Arveson Space on the Siegel Upper Half-space and a von Neumann Type Inequality

2021 ◽  
Vol 93 (6) ◽  
Author(s):  
Nicola Arcozzi ◽  
Nikolaos Chalmoukis ◽  
Alessandro Monguzzi ◽  
Marco M. Peloso ◽  
Maura Salvatori
Keyword(s):  
Half Space ◽  
Type Theorem ◽  
Type Inequality ◽  
Contraction Semigroup ◽  
Von Neumann ◽  
Commuting Operators ◽  
Neumann Type ◽  
Wiener Type ◽  
Multiplier Operators ◽  
Arveson Space

AbstractIn this work we study what we call Siegel–dissipative vector of commuting operators $$(A_1,\ldots , A_{d+1})$$ ( A 1 , … , A d + 1 ) on a Hilbert space $${{\mathcal {H}}}$$ H and we obtain a von Neumann type inequality which involves the Drury–Arveson space DA on the Siegel upper half-space $${{\mathcal {U}}}$$ U . The operator $$A_{d+1}$$ A d + 1 is allowed to be unbounded and it is the infinitesimal generator of a contraction semigroup $$\{e^{-i\tau A_{d+1}}\}_{\tau <0}$$ { e - i τ A d + 1 } τ < 0 . We then study the operator $$e^{-i\tau A_{d+1}}A^{\alpha }$$ e - i τ A d + 1 A α where $$A^{\alpha }=A_1^{\alpha _1}\cdots A^{\alpha _d}_d$$ A α = A 1 α 1 ⋯ A d α d for $$\alpha \in {\mathbb N}_0^d$$ α ∈ N 0 d and prove that can be studied by means of model operators on a weighted $$L^2$$ L 2 space. To prove our results we obtain a Paley–Wiener type theorem for DA and we investigate some multiplier operators on DA as well.

Dilations of one Parameter Semigroups of Positive Contractions on Lp Spaces

1997 ◽  
Vol 49 (4) ◽  
pp. 736-748 ◽  
Author(s):  
Gero Fendler
Keyword(s):  
Continuous Semigroup ◽  
Continuous Group ◽  
Strongly Continuous Semigroup ◽  
Von Neumann ◽  
Lp Spaces ◽  
Discrete Semigroup ◽  
Neumann Type ◽  
Transfer Map

AbstractIt is proved in this note, that a strongly continuous semigroup of (sub)positive contractions acting on an Lp-space, for 1 < p < ∞ p ≠ 2, can be dilated by a strongly continuous group of (sub)positive isometries in a manner analogous to the dilation M. A. Akçoglu and L. Sucheston constructed for a discrete semigroup of (sub)positive contractions. From this an improvement of a von Neumann type estimation, due to R. R.Coifman and G.Weiss, on the transfer map belonging to the semigroup is deduced.

scholarly journals Current-induced crystallisation in Heusler alloy films for memory potentiation in neuromorphic computation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
William Frost ◽  
Kelvin Elphick ◽  
Marjan Samiepour ◽  
Atsufumi Hirohata
Keyword(s):  
Heusler Alloy ◽  
Layer Growth ◽  
Layer By Layer ◽  
Half Metallic ◽  
Alloy Films ◽  
Von Neumann ◽  
Alternative Technologies ◽  
Artificial Synapse ◽  
Neumann Type ◽  
Area Product

AbstractThe current information technology has been developed based on von Neumann type computation. In order to sustain the rate of development, it is essential to investigate alternative technologies. In a next-generation computation, an important feature is memory potentiation, which has been overlooked to date. In this study, potentiation functionality is demonstrated in a giant magnetoresistive (GMR) junction consisting of a half-metallic Heusler alloy which can be a candidate of an artificial synapse while still achieving a low resistance-area product for low power consumption. Here the Heusler alloy films are grown on a (110) surface to promote layer-by-layer growth to reduce their crystallisation energy, which is comparable with Joule heating induced by a controlled current introduction. The current-induced crystallisation leads to the reduction in the corresponding resistivity, which acts as memory potentiation for an artificial GMR synaptic junction.

Embedded Half-Bound States for Potentials of Wigner-Von Neumann Type

1991 ◽  
Vol s3-62 (3) ◽  
pp. 607-646 ◽  
Author(s):  
D. B. Hinton ◽  
M. Klaus ◽  
J. K. Shaw
Keyword(s):  
Bound States ◽  
Von Neumann ◽  
Neumann Type

scholarly journals ENTANGLEMENT, HAAG-DUALITY AND TYPE PROPERTIES OF INFINITE QUANTUM SPIN CHAINS

2006 ◽  
Vol 18 (09) ◽  
pp. 935-970 ◽  
Author(s):  
M. KEYL ◽  
T. MATSUI ◽  
D. SCHLINGEMANN ◽  
R. F. WERNER
Keyword(s):  
Hilbert Spaces ◽  
Quantum Spin ◽  
Xy Model ◽  
Type I ◽  
Quantum Spin Chains ◽  
Haag Duality ◽  
Von Neumann ◽  
Neumann Type ◽  
Left And Right ◽  
Normal States

We consider an infinite spin chain as a bipartite system consisting of the left and right half-chains and analyze entanglement properties of pure states with respect to this splitting. In this context, we show that the amount of entanglement contained in a given state is deeply related to the von Neumann type of the observable algebras associated to the half-chains. Only the type I case belongs to the usual entanglement theory which deals with density operators on tensor product Hilbert spaces, and only in this situation separable normal states exist. In all other cases, the corresponding state is infinitely entangled in the sense that one copy of the system in such a state is sufficient to distill an infinite amount of maximally entangled qubit pairs. We apply this results to the critical XY model and show that its unique ground state φS provides a particular example for this type of entanglement.

scholarly journals Projective algorithms for solving complementarity problems

2002 ◽  
Vol 29 (2) ◽  
pp. 99-113
Author(s):  
Caroline N. Haddad ◽  
George J. Habetler
Keyword(s):  
Linear Complementarity Problem ◽  
Complementarity Problem ◽  
Convex Sets ◽  
Complementarity Problems ◽  
Linear Complementarity ◽  
Von Neumann ◽  
Nonconvex Sets ◽  
Neumann Type ◽  
Successive Over Relaxation ◽  
Projective Algorithms

We present robust projective algorithms of the von Neumann type for the linear complementarity problem and for the generalized linear complementarity problem. The methods, an extension of Projections Onto Convex Sets (POCS) are applied to a class of problems consisting of finding the intersection of closed nonconvex sets. We give conditions under which convergence occurs (always in2dimensions, and in practice, in higher dimensions) when the matrices areP-matrices (though not necessarily symmetric or positive definite). We provide numerical results with comparisons to Projective Successive Over Relaxation (PSOR).

Exponential convergence rates for weighted sums in noncommutative probability space

2016 ◽  
Vol 19 (04) ◽  
pp. 1650027 ◽  
Author(s):  
Byoung Jin Choi ◽  
Un Cig Ji
Keyword(s):  
Probability Space ◽  
Von Neumann Algebra ◽  
Convergence Rates ◽  
Exponential Convergence ◽  
Large Deviation ◽  
Type Inequality ◽  
Independent Random Variables ◽  
Weighted Sums ◽  
Noncommutative Probability ◽  
Von Neumann

We study exponential convergence rates for weighted sums of successive independent random variables in a noncommutative probability space of which the weights are in a von Neumann algebra. Then we prove a noncommutative extension of the result for the exponential convergence rate by Baum, Katz and Read. As applications, we first study a large deviation type inequality for weighted sums in a noncommutative probability space, and secondly we study exponential convergence rates for weighted free additive convolution sums of probability measures.

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