22,360 research outputs found
Volume integrals associated with the inhomegeneous Helmholtz equation. Part 2: Cylindrical region; rectangular region
Results are presented for volume integrals associated with the Helmholtz operator, nabla(2) + alpha(2), for the cases of a finite cylindrical region and a region of rectangular parallelepiped. By using appropriate Taylor series expansions and multinomial theorem, these volume integrals are obtained in series form for regions r r' and r 4', where r and r' are distances from the origin to the point of observation and source, respectively. When the wave number approaches zero, the results reduce directly to the potentials of variable densities
TeV Scale Lee-Wick Fields out of Large Extra Dimensional Gravity
We study the gravitational corrections to the Maxwell, Dirac and Klein-Gorden
theories in the large extra dimension model in which the gravitons propagate in
the (4+n)-dimensional bulk, while the gauge and matter fields are confined to
the four-dimensional world. The corrections to the two-point Green's functions
of the gauge and matter fields from the exchanges of virtual Kaluza-Klein
gravitons are calculated in the gauge independent background field method. In
the framework of effective field theory, we show that the modified one-loop
renormalizable Lagrangian due to quantum gravitational effects contains a TeV
scale Lee-Wick partner of every gauge and matter field as extra degrees of
freedom in the theory. Thus the large extra dimension model of gravity provides
a natural mechanism to the emergence of these exotic particles which were
recently used to construct an extension of the Standard Model.Comment: 17 pages, 3 figures, references added, to appear in Phys. Rev.
Spin entanglement induced by spin-orbit interactions in coupled quantum dots
We theoretically explore the possibility of creating spin quantum
entanglement in a system of two electrons confined respectively in two
vertically coupled quantum dots in the presence of Rashba type spin-orbit
coupling. We find that the system can be described by a generalized Jaynes -
Cummings model of two modes bosons interacting with two spins. The lower
excitation states of this model are calculated to reveal the underlying physics
of the far infrared absorption spectra. The analytic perturbation approach
shows that an effective transverse coupling of spins can be obtained by
eliminating the orbital degrees of freedom in the large detuning limit. Here,
the orbital degrees of freedom of the two electrons, which are described by two
modes of bosons, serve as a quantized data bus to exchange the quantum
information between two electrons. Then a nontrivial two-qubit logic gate is
realized and spin entanglement between the two electrons is created by virtue
of spin-orbit coupling.Comment: 7 pages, 5 figure
Self-similarity under inflation and level statistics: a study in two dimensions
Energy level spacing statistics are discussed for a two dimensional
quasiperiodic tiling. The property of self-similarity under inflation is used
to write a recursion relation for the level spacing distributions defined on
square approximants to the perfect quasiperiodic structure.
New distribution functions are defined and determined by a combination of
numerical and analytical calculations.Comment: Latex, 13 pages including 6 EPS figures, paper submitted to PR
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