Aplicações de biossensores na análise da qualidade de alimentos.

Biossensores; Classificação de biossensores; Desenvolvimento de biossensores; Aplicaçõs de biossensores; Aplicações de biossensores na indústria de alimentos.bitstream/item/33970/1/Dc-117.pd

Strong electron-photon coupling in one-dimensional quantum dot chain: Rabi waves and Rabi wavepackets

We predict and theoretically investigate the new coherent effect of nonlinear quantum optics -- spatial propagation of Rabi oscillations (Rabi waves) in one-dimensional quantum dot (QD) chain. QD-chain is modeled by the set of two-level quantum systems with tunnel coupling between neighboring QDs. The space propagation of Rabi waves in the form of traveling waves and wave packets is considered. It is shown, that traveling Rabi waves are quantum states of QD-chain dressed by radiation. The dispersion characteristics of traveling Rabi waves are investigated and their dependence on average number of photons in wave is demonstrated. The propagation of Rabi wave packets is accompanied by the transfer of the inversion and quantum correlations along the QD-chain and by the transformation of quantum light statistics. The conditions of experimental observability are analyzed. The effect can find practical use in quantum computing and quantum informatics.Comment: 16 pages, 15 figure

Flat-band quantum communication induced by disorder

We show that a qubit transfer protocol can be realized through a flat band hosted by a disordered $XX$ spin-1/2 diamond chain. In the absence of disorder, the transmission becomes impossible due to the compact localized states forming the flat band. When off-diagonal disorder is considered, the degeneracy of the band is preserved but the associated states are no longer confined to the unit cells. By perturbatively coupling the sender and receiver to the flat band, we derive a general effective Hamiltonian resembling a star network model with two hubs. The effective couplings correspond to wavefunctions associated with the flat-band modes. Specific relationships between these parameters define the quality of the quantum-state transfer which, in turn, are related to the degree of localization in the flat band. Our findings establish a framework for further studies of flat bands in the context of quantum communication.Comment: 7 figures, 8 page

A multi-color and Fourier study of RR Lyrae variables in the globular cluster NGC 5272 (M3)

We have performed a detailed study of the pulsational and evolutionary characteristics of 133 RR Lyrae stars in the globular cluster NGC5272 (M3) using highly accurate BVI data taken on 5 separate epochs. M3 seems to contain no less than ~32% of Blazhko stars, and the occurrence and characteristics of the Blazhko effect have been analyzed in detail. We have identified a good number (~ 14%) of overluminous RR Lyrae stars that are likely in a more advanced evolutionary stage off the Zero Age Horizontal Branch (ZAHB). Physical parameters (i.e. temperature, luminosity, mass) have been derived from (B--V) colors and accurate color-temperature calibration, and compared with Horizontal Branch evolutionary models and with the requirements of stellar pulsation theory. Additional analysis by means of Fourier decomposition of the V light curves confirms, as expected, that no metallicity spread is present in M3. Evolution off the ZAHB does not affect [Fe/H] determinations, whereas Blazhko stars at low amplitude phase do affect [Fe/H] distributions as they appear more metal-rich. Absolute magnitudes derived from Fourier coefficients might provide useful average estimates for groups of stars, if applicable, but do not give reliable {\em individual} values. Intrinsic colors derived from Fourier coefficients show significant discrepancies with the observed ones, hence the resulting temperatures and temperature-related parameters are unreliable.Comment: 86 pages, 19 figures, 13 tables, in press A

A general scheme for the effective-mass Schrodinger equation and the generation of the associated potentials

A systematic procedure to study one-dimensional Schr\"odinger equation with a position-dependent effective mass (PDEM) in the kinetic energy operator is explored. The conventional free-particle problem reveals a new and interesting situation in that, in the presence of a mass background, formation of bound states is signalled. We also discuss coordinate-transformed, constant-mass Schr\"odinger equation, its matching with the PDEM form and the consequent decoupling of the ambiguity parameters. This provides a unified approach to many exact results known in the literature, as well as to a lot of new ones.Comment: 16 pages + 1 figure; minor changes + new "free-particle" problem; version published in Mod. Phys. Lett.

Quadratic Effective Action for QED in D=2,3 Dimensions

We calculate the effective action for Quantum Electrodynamics (QED) in D=2,3 dimensions at the quadratic approximation in the gauge fields. We analyse the analytic structure of the corresponding nonlocal boson propagators nonperturbatively in k/m. In two dimensions for any nonzero fermion mass, we end up with one massless pole for the gauge boson . We also calculate in D=2 the effective potential between two static charges separated by a distance L and find it to be a linearly increasing function of L in agreement with the bosonized theory (massive Sine-Gordon model). In three dimensions we find nonperturbatively in k/m one massive pole in the effective bosonic action leading to screening. Fitting the numerical results we derive a simple expression for the functional dependence of the boson mass upon the dimensionless parameter e^{2}/m .Comment: 10 pages, 2 figure

Graded extension of SO(2,1) Lie algebra and the search for exact solutions of Dirac equation by point canonical transformations

SO(2,1) is the symmetry algebra for a class of three-parameter problems that includes the oscillator, Coulomb and Morse potentials as well as other problems at zero energy. All of the potentials in this class can be mapped into the oscillator potential by point canonical transformations. We call this class the "oscillator class". A nontrivial graded extension of SO(2,1) is defined and its realization by two-dimensional matrices of differential operators acting in spinor space is given. It turns out that this graded algebra is the supersymmetry algebra for a class of relativistic potentials that includes the Dirac-Oscillator, Dirac-Coulomb and Dirac-Morse potentials. This class is, in fact, the relativistic extension of the oscillator class. A new point canonical transformation, which is compatible with the relativistic problem, is formulated. It maps all of these relativistic potentials into the Dirac-Oscillator potential.Comment: Replaced with a more potrable PDF versio

Composição florística e fitossociológica de uma vegetação de caatinga na área de reserva legal do Projeto Brígida UHE Itaparica / CHESF, município de Orocó-PE.

O presente estudo foi desenvolvido com o objetivo de contribuir para maior conhecimento da composição florística e fitossocioecológica de uma vegetação de Caatinga na área da Reserva Legal do Projeto Brígida, situada no Município de Orocó-PE.1 CD-ROM