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Now showing items 1-10 of 12

#### Electron-energy-loss and optical-transmittance investigation of Bi2Sr2CaCu2O8

(American Physical Society, 1990-07)

The energy-loss function Im(-1/ε) of Bi2Sr2CaCu2O8 has been measured over the range Eloss=0.8 to 80 eV by transmission electron-energy-loss spectroscopy (EELS) (nonimaging). The energy and momentum resolution were 0.1 eV ...

#### coupling of orthogonal polarization states in a nonlinear birefringent cavity

(Optical Society of America, 1990)

We discuss the coupling of orthogonally polarized beams in a nonlinear cavity and show experimentally how this can be used to implement gates or latches in which one polarization state is switched by another. These devices ...

#### Resonating-valence-bond wave function for the two-dimensional Heisenberg model on a triangular lattice

(American Physical Society, 1990-06)

A resonating-valence-bond (RVB) wave function for the triangular lattice is constructed by following the renormalized Hamiltonian approach (or Gutzwiller approximation) successfully developed for the square lattice. This ...

#### Theoretical study of effective magnetic interactions in high-Tc Cu oxides

(American Physical Society, 1990-11)

Starting from a two-band Hubbard model for cupric oxides and using perturbation theory, we study the effect of a small O-O hopping term tp on the parameters of the single-band t-J model. It is found that as long as the ...

#### on the Levinson theorem for Dirac operators

(AIP Publishing, 1990-01)

For the Dirac equation with potential V(r) obeying ∫∞ 0(1+r)‖V(r)‖d r<∞ we prove a relativistic version of Levinson’s theorem that relates the number of bound states in the spectral gap [−m,m] to the variation of an ...

#### Remarks on "On the coefficient of nonlinearity in nonlinear acoustics"

(Acoustical Society of America, 1990-10)

Through an alternate analysis, the results of Hamilton and Blackstock [J. Acoust. Soc. Am. 83, 74-77 (1988)] are reviewed and a new interpretation is presented. In this view, the nonlinearity of the momentum equation is ...

#### Mobile spin bags and their interaction in the spin-density-wave background

(American Physical Society, 1990-02)

The motion of one doped hole in the spin-density-wave background has been studied by the variational approach. A spin-bag solution for the doped hole has been obtained that applies in the weak- and intermediate-coupling ...

#### Incoherent Bandpass Spatial-Filtering with Longitudinal Periodicity

(Optical Society of America, 1990-09-01)

We explore the possibility of realizing bandpass filtering with longitudinal periodicity in incoherent systems. The necessary condition for spatial filtering to be longitudinally periodic is derived. Results indicate that ...

#### Finite-basis many-electron approximation to the Anderson model

(American Physical Society, 1990-03)

A relatively simple many-electron basis is used to construct a matrix for the Anderson impurity Hamiltonian. The basis states are each valid in the thermodynamic limit. The approximate ground-state energy compares well ...