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Search Results: 1 - 10 of 324950 matches for " S Kryszewski "
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Stratificational and antipodean properties of boundary states for N x N density matrices
S Kryszewski,M Zachcia?,? Szparaga
Physics , 2007,
Abstract: We investigate the space of N x N dimensional density matrices. We show that there exist strata such that boundary states \rho_{p} with p zero eigenvalues lie on or outside the spheres with radii r_{p}=\sqrt{p/N(N-p)}. Moreover, we show that if in a certain direction there is a boundary state with q=N-p equal eigenvalues, then in the opposite (antipodean) direction exists a boundary state with p=N-q equal eigenvalues.
The Structure of Incomplete Destructive Breakdown Spots in Thin Polymer Films
S. Sapieha,W. Jablonski,M. Kryszewski
Active and Passive Electronic Components , 1974, DOI: 10.1155/apec.1.65
Abstract:
Topological structure of solution sets of differential inclusions: the constrained case
Wojciech Kryszewski
Abstract and Applied Analysis , 2003, DOI: 10.1155/s1085337503204115
Abstract: We survey and announce some current results on the existence, the viability, and the topological structure of the viable solutions of differential equations and inclusion in Banach spaces under set constraints. Some new results concerning semilinear differential inclusions with state variables constrained to the so-called regular and strictly regular sets, together with their applications, are presented and discussed.
Leczenie zachowawcze choroby refluksowej prze yku
Andrzej Kryszewski
Polish Gastroenterology , 1998,
Abstract: Leczenie choroby refluksowej prze yku (gastroesophageal reflux disease - GERD) powinno obejmowa wszystkie czynniki patogenetyczne i mo e by podzielone na trzy etapy. Pierwszy obejmuje modyfikacj zachowań (zmian stylu ycia), w drugim stosowana jest farmakoterapia, a trzeci to leczenie chirurgiczne. W agodnych formach GERD zaleca si zmian stylu ycia. Leczenie farmakologiczne ma na celu redukcj kwasoty przez zastosowanie antagonistów receptorów H2 (H2RA) i inhibitorów pompy protonowej (proton pomp inhibitors - PPI) oraz popraw motoryki prze yku i o dka. W ostrym leczeniu zapaleń prze yku III lub IV stopnia lekiem z wyboru s PPI lub cyzapryd w po czeniu z wysokimi dawkami H2RA. Najlepsze wyniki w leczeniu podtrzymuj cym uzyskuje si , podaj c leki z grupy PPI. Antyrefluksowe leczenie chirurgiczne nale y stosowa u ludzi m odych, nie reaguj cych na leczenie zachowawcze, w powik aniach GERD oraz w przypadku stwierdzenia objawów ze strony uk adu oddechowego zwi zanych z GERD.
Utajona encefalopatia w trobowa: diagnostyka i znaczenie
Magdalena Stojek,Andrzej Kryszewski
Polish Gastroenterology , 2002,
Abstract: U chorych z marskosci w troby bez uchwytnych klinicznie zaburzeń czynno ci o rodkowego uk adu nerwowego cz sto wyst puj mierzalne ubytki czynno ci poznawczych, okre lane mianem utajonej encefalo-patii w trobowej (uew). G ówne zaburzenia stwierdzane w uewto apraksja konstrukcyjna, wyd u enie czasu reakcji na bod ce, zaburzenia funkcji uwagi. Utajona encefalopatia w trobowa jest czynnikiem pogarszaj cym rokowanie co do d ugo ci prze ycia, jej wyst pienie jest tak e zwi zane z wi kszym ryzykiem rozwini cia si pe noobjawowej encefalopatii. Pogarsza ona jako ycia chorych z marskosci i utrudnia wykonywanie pracy zawodowej. Nie ustalono dotychczas jednolitych zasad rozpoznawania uew. Obecnie najwi ksz rol w diagnostyce odgrywaj testy psychometryczne, mimo ich oczywistych ograniczeń, takich jak zale no od wspó pracy pacjenta, niska powtarzalno i wyst powanie efektu uczenia si . W przysz o ci nale y spodziewa si wzrostu znaczenia metod neurofizjologicznych, takich jak potencja y wywo ane. Wleczeniu uew stosowano wiele metod, m.in. diet ubogobia kow , flumazenil, substytucje aminokwasów rozga zionych, preparaty cynku. Nie zosta o jednoznacznie dowiedzione, czy w czenie leczenia mo e zapobiec rozwini ciu si pe noobjawowej ew.
Alternative representation of N \times N density matrix
Stanislaw Kryszewski,Mateusz Zachcial
Physics , 2006,
Abstract: We use polarization operators known from quantum theory of angular momentum to expand the $N \times N$ dimensional density operators. Thereby, we construct generalized Bloch vectors representing density matrices. We study their properties and derive positivity conditions for any $N$. We also apply the procedure to study Bloch vector space for a qubit and a qutrit.
On the positivity of Bloch-Boltzmann equations
Stanislaw Kryszewski,Justyna Czechowska
Physics , 2004,
Abstract: In a large variety of spectroscopical applications Bloch-Boltzmann equations (BBE) play an essential role. They describe the evolution of the reduced density operator of an active atom which is coupled to radiation (Bloch part) and which interacts collisionally with the perturber gas (Boltzmann part). The standard approach to the collisional part is well-known from the literature. It preserves hermiticity and normalization, but the question whether it preserves positivity seems to remain open. The completely positive BBE were recently derived via the general master equation techniques. These two approaches are applied for a model of n-level nondegenerate atom. We show that within this model both approaches to the collisional part of BBE are equivalent -- give the same physical predictions. The approach based upon master equation techniques guarantees the preservation of hermiticity, normalization and positivity. The proven equivalence ascertains that the standard approach also preserves positivity. Moreover, some aspects of the standard derivation (which atomic states do contribute to the evolution) are clarified by the established equivalence.
The Constrained Krasnosel'skii Formula for Parabolic Differential Inclusions
Wojciech Kryszewski,Jakub Siemianowski
Mathematics , 2015,
Abstract: We consider a constrained evolution inclusions of parabolic type \eqref{inkluzja-rozn} involving an $m$-dissipative linear operator and the source term of multivalued type in a Banach space and topological properties of the solution map. We show a relation between the constrained fixed point index of the Krasnosel'skii--Poincar\'{e} operator of translation along trajectories associated with \eqref{inkluzja-rozn} and the appropriately defined constrained degree of $A + F\le 0 , \cdot \pr $ of the right-hand side in \eqref{inkluzja-rozn}. Our results extend those of \cite{cw} and \cite{gab-krysz}.
Bifurcation from infinity for an asymptotically linear Schr?dinger equation
Wojciech Kryszewski,Andrzej Szulkin
Mathematics , 2014,
Abstract: We consider an asymptotically linear Schr\"odinger equation $-\Delta u + V(x)u = \lambda u + f(x,u), \ x\in R^N$, and show that if $\lambda_0$ is an isolated eigenvalue for the linearization at infinity, then under some additional conditions there exists a sequence $(u_n,\lambda_n)$ of solutions such that $\|u_n\|\to\infty$ and $\lambda_n\to\lambda_0$. Our results extend some recent work by Stuart. We use degree theory if the multiplicity of $\lambda_0$ is odd and Morse theory (or more specifically, Gromoll-Meyer theory) if it is not.
Completely Positive Bloch-Boltzmann Equations
Robert Alicki,Stanis?aw Kryszewski
Physics , 2002, DOI: 10.1103/PhysRevA.68.013809
Abstract: The density operator of the arbitrary physical system must be positive definite. Employing the general master equation technique which preserves this property we derive equations of motion for the density operator of an active atom which interacts collisionally with the reservoir of perturber atoms. The obtained general relations applied to the two-level atom yield Bloch-Boltzmann equations (BBE). The form of the BBE obtained by us differs from that known from literature which, as we show, are not guaranteed to preserve the required positivity. We argue that our results are the correct ones and as such should be used in practical applications. Moreover, the structure and the terms which appear in our set of BBE seem to allow simpler and more straightforward physical interpretation.
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