7,564 research outputs found

    Transverse tunneling current through guanine traps in DNA

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    The current - voltage dependence of the transverse tunneling current through the electron or hole traps in a DNA is investigated. The hopping of the charge between the sites of the trap and the charge-phonon coupling results in a staircase structure of the I-V curve. For typical parameters of the DNA molecule the energy characteristics of a DNA trap can be extracted from the I-V dependence, viz., for a small gate voltage the phonon frequency and for a large gate voltage the hopping integral can be found from the positions of the steps in the I-V curve. Formation of the polaronic state also results in the redistribution of the tunneling current between the different sites of the traps

    Temperature dependence of spin polarizations at higher Landau Levels

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    We report our results on temperature dependence of spin polarizations at ν=1\nu=1 in the lowest as well as in the next higher Landau level that compare well with recent experimental results. At ν=3\nu=3, except having a much smaller magnitude the behavior of spin polarization is not much influenced by higher Landau levels. In sharp contrast, for filling factor ν=83\nu=\frac83 we predict that unlike the case of ν=23\nu=\frac23 the system remains fully spin polarized even at vanishingly small Zeeman energies.Comment: 4 pages, REVTEX, and 3 .ps files, To be published in Physical Review Letter

    Analytic Coulomb matrix elements in a three-dimensional geometry

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    Using a complete basis set we have obtained an analytic expression for the matrix elements of the Coulomb interaction. These matrix elements are written in a closed form. We have used the basis set of the three-dimensional isotropic quantum armonic oscillator in order to develop our calculations, which can be useful when treating interactions in localized systems.Comment: 3 pages, errat

    Topological entropy of realistic quantum Hall wave functions

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    The entanglement entropy of the incompressible states of a realistic quantum Hall system are studied by direct diagonalization. The subdominant term to the area law, the topological entanglement entropy, which is believed to carry information about topologic order in the ground state, was extracted for filling factors 1/3, 1/5 and 5/2. The results for 1/3 and 1/5 are consistent with the topological entanglement entropy for the Laughlin wave function. The 5/2 state exhibits a topological entanglement entropy consistent with the Moore-Read wave function.Comment: 6 pages, 6 figures; improved computations and graphics; added reference

    On the MHD load and the MHD metage

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    In analogy with the load and the metage in hydrodynamics, we define magnetohydrodynamic load and magnetohydrodynamic metage in the case of magnetofluids. They can be used to write the magnetic field in MHD in Clebsch's form. We show how these two concepts can be utilised to derive the magnetic analogue of the Ertel's theorem and also, how in the presence of non-trivial topology of the magnetic field in the magnetofluid one may associate the linking number of the magnetic field lines with the invariant MHD loads. The paper illustrates that the symmetry translation of the MHD metage in the corresponding label space generates the conservation of cross helicity.Comment: Some issues in the paper are yet to be addressed. Constructive critisicms are most welcom
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