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Ioan Sturzu

Publications and source records attributed to Ioan Sturzu.

9 recordsLinked to original sources
arXiv2025

Determination of Quantum Instrument Parameters for a Stern-Gerlach Non-ideal Device

In the Stern--Gerlach (SG) apparatus, when the filtering is not perfect, the fermion state transformation is done by non-ideal devices. Such an apparatus is described in quantum mechanics by quantum instruments. It will be shown how the parameters of this instrument can be expressed in terms of some experimentally accessible quantities. These relations are valid both for single and successive measurements. In the latter case, the measuring device is rotated with respect to the first one.

quant-ph↗
arXiv2004

Taylor expansion for an operator function

A simple version for the extension of the Taylor theorem to the operator functions was found. The expansion was done with respect to a value given by a diagonal matrix for the non-commutative case, and the coefficients are given both by recurrence relations and Cauchy integrals.

math-ph↗
arXiv2002

State transformations after quantum fuzzy measurements

Using a standard fuzzification procedure and the dynamical map in Heisenberg picture, a new expression for the state transformation after a fuzzy filter measurement, subject to covariance conditions, was obtained and some calculations were done to distinguish its properties from the those of the usual solution.

quant-ph↗
arXiv2002

Topics on the stochastical treatement of an open quantum system

The paper shortly presents the role of Stochastic Processes Theory in the present day Quantum Theory, and the relation to Operational Quantum Physics. The dynamics of an open quantum system is studied on a usual example from Quantum Optics, suggesting the definition of a Neumark-type dilation for the non-thermal states.

quant-ph↗
arXiv2002

On the function sum(-k^2/s^2)

Some properties of the function$ ψ(s)=\sum\limits_{k=-\infty}^\infty {% \exp (-\frac{k^2}{s^2}})$ are studied, and an interpolation formula is given.

quant-ph↗