1,762 research outputs found
Emission spectrum and geometric phase in deformed Jaynes-Cummings model
Abstract The emission spectrum of a qubit (two-level atom) system that interacts with a field in the framework of parity deformations is investigated in this paper. The model consists of a qubit coupled to a single-mode field within the parity deformed Jaynes-Cummings model (PDJCM) based on the λ -analog of the quantum harmonic oscillator algebra. We numerically evaluate the atomic emission spectrum (AES), by considering the influence of the deformed parameter and half-band-width of the spectrometer. Moreover, the dependence of the spectrum peaks on the detuning parameter is discussed. Finally, we study the variation of the geometric phase of the whole system state modelled by the PDJCM in terms of the main physical parameters
Entanglement and photon statistics of two dipole–dipole coupled superconducting qubits with Kerr-like nonlinearities
Abstract The engineering of Kerr and time-dependent coupling interactions is of great attention for treating quantum information in quantum systems and for investigating the collective behavior of large numbers of interacting particles in a cavity-qubit network. In this manuscript, we investigate the time evolution of the entanglement and some nonclassical properties of two superconducting qubits interacting with a single-mode field in the presence of a Kerr-like medium and dipole–dipole interaction without and with time-dependent coupling effect. We show that a slight alteration in the interaction, detuning, and Kerr parameters might cause a change in the entanglement of subsystem states during the evolution. By taking into account the influence of the different physical parameters, we show the statistical distributions produced in the photons of the single mode field through the calculation of the Mandel's parameter. Finally, we find that the time-dependent Mandel's parameter not only provide the statistical properties of the field, but also include the information of quantum entanglement for the subsystem states
Quantum correlations between each qubit in a two-atom system and the environment in terms of interatomic distance
The quantum correlations between a qubit and its environment are described
quantitatively in terms of interatomic distance. Specifically, considering a
realistic system of two two-level atoms and taking into account the
dipole-dipole interaction and collective damping, the quantum entanglement and
quantum discord are investigated, during the dissipative process, as a function
of the interatomic distance. For atoms that are initially maximally entangled,
it turns out that there is a critical distance where each atom is maximally
quantum correlated with its environment. Counterintuitively, the approach of
the two atoms can maximize the entanglement between each one and the
environment and, even at the same distance, minimize the loss of entanglement
between the pair.Comment: 5 pages, 3 figure
Role of <i>Bifidobacterium bifidum</i> and plant food extracts in improving microflora and biochemical and cytogenetic parameters in adjuvant arthritis.
The aim of the present research was to discover plant food extracts and probiotics that may have bioactivity towards chronic inflammation. Three plant food extract mixtures expected to be rich in phenolic compounds, carotenoids and tocopherols were prepared. The anti-inflammatory activity of the different mixtures as well as probiotic bacteria (<i>Bifidobacterium bifidum</i>) were evaluated in adjuvant arthritis in rats. The anti-inflammatory effect, mechanism of action and safety of the three mixtures and <i>Bifidobacterium bifidum</i> were studied by measuring the size of inflammation and the determination of inflammatory and oxidative stress biomarkers, colonic bacteria profile and specific cytogenetic parameters. The contents of tocopherols, β-carotene and phenolic compounds in the mixtures were determined. The results show that the tested mixtures and <i>Bifidobacterium bifidum</i> possess promising anti-inflammatory effects. The mechanism of action seems to involve a reduction in oxidative stress and inflammatory biomarkers and an effect on colonic microflora. Genotoxicity and DNA fragmentation induced by adjuvant arthritis were prevented after supplementation with the tested mixtures.<br><br>El objetivo de la presente investigación fue encontrar extractos de alimentos vegetales y probióticos que puedan tener bioactividad hacía la inflamación crónica. Mezclas de tres extractos de alimentos vegetales conocidos por su riqueza en compuestos fenólicos, carotenoides y tocoferoles han sido preparadas. La actividad anti-inflamatoria de las diferentes mezclas y de bacterias probióticas (<i>Bifidobacterium bifidum</i>) fue evaluada en artritis adyuvante en ratas. El efecto anti-inflamatorio, mecanismo de acción y salubridad de las tres mezclas y de <i>Bifidobacterium bifidum</i> ha sido estudiado mediante la medida del tamaño de la inflamación y la determinación de biomarcadores de inflamación y estrés oxidativo, del perfil de bacterias del colón y de parámetros citogenéticos específicos. El contenido de tocoferoles, β-caroteno y compuestos fenólicos en las mezclas fue determinado. Los resultados muestran que las mezclas y los <i>Bifidobacterium bifidum</i> poseen un prometedor efecto anti-inflamatorio. El mecanismo de acción parece involucrar una reducción de los biomarcadores inflamatorios y del estrés oxidativo y tiene un efecto sobre la microflora del colón. La fragmentación del DNA y la genotoxicidad inducida por la artritis adjuvante fue prevenida con la suplementación de las mezclas ensayadas
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