The energy dependence of the πN\pi N amplitude and the three-nucleon interaction

By calculating the contribution of the $\pi-\pi$ three-body force to the three-nucleon binding energy in terms of the $\pi N$ amplitude using perturbation theory, we are able to determine the importance of the energy dependence and the contribution of the different partial waves of the $\pi N$ amplitude to the three-nucleon force. A separable representation of the non-pole $\pi N$ amplitude allows us to write the three-nucleon force in terms of the amplitude for $NN\rightarrow NN^*$, propagation of the $NNN^*$ system, and the amplitude for $NN^*\rightarrow NN$, with $N^*$ being the $\pi N$ quasi-particle amplitude in a given state. The division of the $\pi N$ amplitude into a pole and non-pole gives a procedure for the determination of the $\pi NN$ form factor within the model. The total contribution of the three-body force to the binding energy of the triton for the separable approximation to the Paris nucleon-nucleon potential (PEST) is found to be very small mainly as a result of the energy dependence of the $\pi N$ amplitude, the cancellation between the $S$- and $P$-wave $\pi N$ amplitudes, and the soft $\pi NN$ form factor.Comment: RevTex file, 36 pages, 10 figures available from authors: [email protected]

Degeneracy breaking and intervalley scattering due to short-ranged impurities in finite single-wall carbon nanotubes

We present a theoretical study of degeneracy breaking due to short-ranged impurities in finite, single-wall, metallic carbon nanotubes. The effective mass model is used to describe the slowly varying spatial envelope wavefunctions of spinless electrons near the Fermi level at two inequivalent valleys (K-points) in terms of the four component Dirac equation for massless fermions, with the role of spin assumed by pseudospin due to the relative amplitude of the wave function on the sublattice atoms (``A'' and ``B''). Using boundary conditions at the ends of the tube that neither break valley degeneracy nor mix pseudospin eigenvectors, we use degenerate perturbation theory to show that the presence of impurities has two effects. Firstly, the position of the impurity with respect to the spatial variation of the envelope standing waves results in a sinusoidal oscillation of energy level shift as a function of energy. Secondly, the position of the impurity within the hexagonal graphite unit cell produces a particular 4 by 4 matrix structure of the corresponding effective Hamiltonian. The symmetry of this Hamiltonian with respect to pseudospin flip is related to degeneracy breaking and, for an armchair tube, the symmetry with respect to mirror reflection in the nanotube axis is related to pseudospin mixing.Comment: 20 pages, 10 eps figure

Coupled ion - nanomechanical systems

We study ions in a nanotrap, where the electrodes are nanomechanical resonantors. The ions play the role of a quantum optical system which acts as a probe and control, and allows entanglement with or between nanomechanical resonators.Comment: 4 pages, 2 figures, submitted for publicatio

Phase mixing of shear Alfvén waves as a new mechanism for electron acceleration in collisionless, kinetic plasmas

Particle-in-cell (kinetic) simulations of shear Alfv´en wave (AW) interaction with one-dimensional, across the uniform-magnetic field, density inhomogeneity (phase mixing) in collisionless plasma were performed for the first time. As a result, a new electron acceleration mechanism is discovered. Progressive distortion of the AW front, due to the differences in local Alfv´en speed, generates electrostatic fields nearly parallel to the magnetic field, which accelerate electrons via Landau damping. Surprisingly, the amplitude decay law in the inhomogeneous regions, in the kinetic regime, is the same as in the MHD approximation described by Heyvaerts and Priest (1983 Astron. Astrophys. 117 220)

Chirality Selection in Open Flow Systems and in Polymerization

As an attempt to understand the homochirality of organic molecules in life, a chemical reaction model is proposed where the production of chiral monomers from achiral substrate is catalyzed by the polymers of the same enatiomeric type. This system has to be open because in a closed system the enhanced production of chiral monomers by enzymes is compensated by the associated enhancement in back reaction, and the chiral symmetry is conserved. Open flow without cross inhibition is shown to lead to the chirality selection in a general model. In polymerization, the influx of substrate from the ambience and the efflux of chiral products for purposes other than the catalyst production make the system necessarily open. The chiral symmetry is found to be broken if the influx of substrate lies within a finite interval. As the efficiency of the enzyme increases, the maximum value of the enantiomeric excess approaches unity so that the chirality selection becomes complete.Comment: 8 pages, 4 figure

Disturbances of both cometary and Earth's magnetospheres excited by single solar flares

In the solar wind a comet plays the role of a windvane that moves three-dimensionally in the heliomagnetosphere. Among the solar systems bodies, only comets have a wide range of inclination angles of their orbital planes to the ecliptic plane ranging from 0 to 90 deg. Therefore, observations of cometary plasma tails are useful in probing the heliomagnetospheric conditions in the high heliolatitudinal region. A comet can be compared to a polar-orbiting probe encircling the Sun. We will introduce two rare cases in which the magnetospheres of both the comet and the Earth are disturbed by a single solar flare

Gap opening in graphene by simple periodic inhomogeneous strain

Using ab-initio methods, we show that the uniform deformation either leaves graphene (semi)metallic or opens up a small gap yet only beyond the mechanical breaking point of the graphene, contrary to claims in the literature based on tight-binding (TB) calculations. It is possible, however, to open up a global gap by a sine-like one-dimensional inhomogeneous deformation applied along any direction but the armchair one, with the largest gap for the corrugation along the zigzag direction (~0.5 eV) without any electrostatic gating. The gap opening has a threshold character with very sharp rise when the ratio of the amplitude A and the period of the sine wave deformation lambda exceeds (A/lambda)_c ~0.1 and the inversion symmetry is preserved, while it is threshold-less when the symmetry is broken, in contrast with TB-derived pseudo-magnetic field models.Comment: 6 pages, 6 figures; (v2) added figures illustrating opening gap in Graphene mesh on BN, expanded analysis illustrating absence of pseudo-magnetic fields in deformed Graphen

Divine Adoption in the Confessions of the Reformation Period

Boer, E.A. de [Promotor]Vlastuin, W. van [Copromotor

Calculation of the Self-energy of Open Quantum Systems

We propose an easy method of calculating the self-energy of semi-infinite leads attached to a mesoscopic system.Comment: 6 pages, 2 figures, published in J. Phys. Soc. Jp