Search results for "Matematica"

Non-Selfadjoint Operators in Quantum Physics: Mathematical Aspects

2015

A unique discussion of mathematical methods with applications to quantum mechanics Non-Selfadjoint Operators in Quantum Physics: Mathematical Aspects presents various mathematical constructions influenced by quantum mechanics and emphasizes the spectral theory of non-adjoint operators. Featuring coverage of functional analysis and algebraic methods in contemporary quantum physics, the book discusses the recent emergence of unboundedness of metric operators, which is a serious issue in the study of parity-time-symmetric quantum mechanics. The book also answers mathematical questions that are currently the subject of rigorous analysis with potentially significant physical consequences. In add…

Quantum dynamics for classical systems

2012

Transition to ballistic regime for heat transport in helium II

2014

The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter-Mellinck regime of turbulent superfluids, are extended to describe the transition to ballistic regime in narrow channels wherein the radius $R$ is comparable to (or smaller than) the phonon mean-free path $\ell$ in superfluid helium. To do so we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads f…

Some classes of quasi *-algebras

2022

In this paper we will continue the analysis undertaken in [1] and in [2] [20] our investigation on the structure of Quasi-local quasi *-algebras possessing a sufficient family of bounded positive tracial sesquilinear forms. In this paper it is shown that any Quasi-local quasi *-algebras (A, A0), possessing a ”sufficient state” can be represented as non-commutative L2- spaces.

Representations and derivations of quasi ∗-algebras induced by local modifications of states

2009

Abstract The relationship between the GNS representations associated to states on a quasi ∗-algebra, which are local modifications of each other (in a sense which we will discuss) is examined. The role of local modifications on the spatiality of the corresponding induced derivations describing the dynamics of a given quantum system with infinite degrees of freedom is discussed.

Representations of Quasi–local quasi *–algebras and non–commutative integration

2013

In this paper we are going to continue the analysis undertaken in [1] and [2] about the investigation on Quasi-local quasi *-algebras and their structure. Our aim is to show that any *-semisimple Quasi-local quasi *-algebra (A,A0) can be represented as a class of non-commutative L1-spaces.

Common fixed point results on quasi-Banach spaces and integral equations

2013

In this paper we obtain fixed and common fixed point theorems for self-mappings defined on a closed and convex subset C of a quasi-Banach space. We give also a constructive method for finding the common fixed points of the involved mappings. As an application we obtain a result of the existence of solutions of integral equations.

Quasi-Continuous Vector Fields on RCD Spaces

2021

In the existing language for tensor calculus on RCD spaces, tensor fields are only defined $\mathfrak {m}$ -a.e.. In this paper we introduce the concept of tensor field defined ‘2-capacity-a.e.’ and discuss in which sense Sobolev vector fields have a 2-capacity-a.e. uniquely defined quasi-continuous representative.

Quasi-local quasi -algebras of measurable operators

2011

In this paper we will continue the analysis undertaken in [1] and in [2] our investigation on the structure of Quasi-local quasi *-algebras. In this paper it is shown that any Quasi-local quasi -algebras (A;A_0), can be represented as a class of Banach C-modules called CQ-algebra of measurable operators in Segal's sense.

On Commuting Quasi-Nilpotent Operators that are Injective

2022

Banach space operators that commute with an injective quasi-nilpotent operator, 11 such as the Volterra operator, inherit spectral and Fredholm properties, relating in 12 particular to the Weyl spectra.