7 research outputs found
The effect of dynamical quark mass in the calculation of strange quark star structure
We have discussed dynamical behavior of strange quark matter components, in
particular the effects of density dependent quark mass on the equation of state
of strange quark matter. Dynamical masses of quarks have been computed within
Nambu-Jona-Lasinio (NJL) model, then we have done the strange quark matter
calculations employing the MIT bag model with these dynamical masses. For the
sake of comparing dynamical mass interaction with QCD quark-quark interaction,
we have considered the one-gluon-exchange term as the effective interaction
between quarks for MIT bag model. Our dynamical approach illustrates an
improvement for the obtained values of equation of state. We have also
investigated the structure of strange quark star using
Tolman-Oppenheimer-Volkoff (TOV) equations for all applied models. Our results
show that the dynamical mass interaction leads to lower values for the
gravitational mass.Comment: 18 pages, 1 table, 7 figure
Complete positivity, finite-temperature effects, and additivity of noise for time-local qubit dynamics
We present a general model of qubit dynamics which entails pure
dephasing and dissipative time-local master equations. This allows us to
describe the combined effect of thermalization and dephasing beyond the
usual Markovian approximation. We investigate the complete positivity
conditions and introduce a heuristic model that is always physical and
provides the correct Markovian limit. We study the effects of
temperature on the non-Markovian behavior of the system and show that
the noise additivity property discussed by Yu and Eberly [Phys. Rev. Lett. 97, 140403 (2006)] holds beyond the Markovian limit.</p
The Automorphism and Coexistence of The Quantum Effects
This work is a study on the symmetry groups of quantum mechanics accompanied by its applications on the coexistence of qubit effects. We surveyed among some of the mappings known as preservers on the set of quantum effects for their role in conserving specific structures that are important in quantum mechanics. Since the preserves in this work mainly target the quantum effects, we provided principals of its corresponding algebra known as effect algebra. Then we advanced, to study the relations between some of these preservers (here we mean automorphisms) by channels operate on qubit effects. The channels are in convex form and we investigate the role of their convex parameters in conserving or breaking the coexistence of two qubit effects. The preserver that we are interested in is a bijective map which preserves the order and coexistence of effects in both directions. Of course, the coexistence of qubit effects can also be studied in the language of coexistence and compatibility of observables. Then our task is to study the coexistence of observables when there are only two effects in their outcome sets. This task has been studied for observables with arbitrary number of effects in their outcome sets [48]. The bounds they have found for the channels convex parameters are independent of that number. However, when the case narrows for limited number outcomes no analytic solution is available, and the study should be carried numerically. Here, we considered observables each having only two nontrivial effects in their out come sets, and asked for the demanding conditions that break their compatibility partially or completely.Siirretty Doriast
Prevalence of Oxyuriasis and its Influencing Factors in Elected Kindergartens in Ali Abad-e-Katoul, North of Iran
Background: Enterobius vermicularis (formerly Oxyuriasis vermicularis), is a prevalent parasitic infection especially in preschool children worldwide. The present study aimed to explore the prevalence of Oxyuriasis and its influencing factors in kindergartens.Materials and Methods: A cross-sectional study was conducted on 175 children using multi-stage sampling method in Ali Abad-e-Katoul city- Iran in 2015 year. Data were collected using a three-part demographic questionnaire including personal characteristics, predisposing factor of infection, and clinical symptoms. Possibility of infection was tested by Graham method. Data were also analyzed using SPSS software (version 18). Significant level was also considered significant a