Formalism for obtaining nuclear momentum distributions by the Deep Inelastic Neutron Scattering technique

We present a new formalism to obtain momentum distributions in condensed matter from Neutron Compton Profiles measured by the Deep Inelastic Neutron Scattering technique. The formalism describes exactly the Neutron Compton Profiles as an integral in the momentum variable $y$. As a result we obtain a Volterra equation of the first kind that relates the experimentally measured magnitude with the momentum distributions of the nuclei in the sample. The integration kernel is related with the incident neutron spectrum, the total cross section of the filter analyzer and the detectors efficiency function. A comparison of the present formalism with the customarily employed approximation based on a convolution of the momentum distribution with a resolution function is presented. We describe the inaccuracies that the use of this approximation produces, and propose a new data treatment procedure based on the present formalism.Comment: 11 pages, 8 figure

Electron correlation effects in a wide channel from the ν=1\nu =1 quantum Hall edge states

The spatial behavior of Landau levels (LLs) for the $nu=1$ quantum Hall regime at the edge of a wide channel is studied in a self-consistent way by using a generalized local density approximation proposed here. Both exchange interaction and strong electron correlations, due to edge states, are taken into account. They essentially modify the spatial behavior of the occupied lowest spin-up LL in comparison with that of the lowest spin-down LL, which is totally empty. The contrast in the spatial behavior can be attributed to a different effective one-electron lateral confining potentials for the spin-split LLs. Many-body effects on the spatially inhomogeneous spin-splitting are calculated within the screened Hartree-Fock approximation. It is shown that, far from the edges, the maximum activation energy is dominated by the gap between the Fermi level and the bottom of the spin-down LL, because the gap between the Fermi level and the spin-up LL is much larger. In other words, the maximum activation energy in the bulk of the channel corresponds to a highly asymmetric position of the Fermi level within the gap between spin-down and spin-up LLs in the bulk. We have also studied the renormalization of the edge-state group velocity due to electron correlations. The results of the present theory are in line with those suggested and reported by experiments on high quality samples.Comment: 9 pages, 4 figure

Repulsion of Single-well Fundamental Edge Magnetoplasmons in Double Quantum Wells

A {\it microscopic} treatment of fundamental edge magnetoplasmons (EMPs) along the edge of a double quantum well (DQW) is presented for strong magnetic fields, low temperatures, and total filling factor \nu=2. It is valid for lateral confining potentials that Landau level (LL) flattening can be neglected. The cyclotron and Zeeman energies are assumed larger than the DQW energy splitting \sqrt{\Delta^2 +4T^2}, where \Delta is the splitting of the isolated wells and T the tunneling matrix element. %hen calculated unperturbed density profile is sharp at the edge. Using a random-phase approximation (RPA), which includes local and nonlocal contributions to the current density, it is shown that for negligible tunnel coupling 2T << \Delta the inter-well Coulomb coupling leads to two DQW fundamental EMPs which are strongly renormalized in comparison with the decoupled, single-well fundamental EMP. These DQW modes can be modified further upon varying the inter-well distance d, along the z axis, and/or the separation of the wells' edges \Delta y along the y axis. The charge profile of the {\it fast} and {\it slow} DQW mode varies, respectively, in an {\it acoustic} and {\it optical} manner along the y axis and is not smooth on the \ell_{0} scale. For strong tunneling \Delta\alt 2T these DQW modes are essentially modified when \Delta is changed by applying a transverse electric field to the DQW.Comment: Text 18 pages in Latex/Revtex/Preprint format, 2 Postscript figure

Random-phase Approximation Treatment Of Edge Magnetoplasmons: Edge-state Screening And Nonlocality

A random-phase approximation (RPA) treatment of edge magnetoplasmons (EMP) is presented for strong magnetic fields, low temperatures, and integer filling factors \nu. It is valid for negligible dissipation and lateral confining potentials smooth on the scale of the magnetic length \ell_{0} but sufficiently steep that the Landau-level (LL) flattening can be neglected. LL coupling, screening by edge states, and nonlocal contributions to the current density are taken into account. In addition to the fundamental mode with typical dispersion relation \omega\sim q_x \ln(q_{x}), fundamental modes with {\it acoustic} dispersion relation \omega\sim q_x are obtained for \nu>2. For \nu=1,2 a {\bf dipole} mode exists, with dispersion relation \omega\sim q_x^3, that is directly related to nonlocal responses.Comment: Text 12 pages in Latex/Revtex format, 4 Postscript figure

Golden buttercups : idyll

Gift of Dr. Mary Jane Esplen.Piano [instrumentation]F [key]Moderato [tempo]Popular song [form/genre]Woman flowers field town [illustration]De Takacs [engraver]Publisher's advertisement on inside back cover and back cover [note

Someone is waiting at home sweet home

Gift of Dr. Mary Jane Esplen.Piano vocal 1st violin mandolin [instrumentation]When alone some time you wander [first line]Someone is waiting at home sweet home [first line of chorus]B flat [key]Waltz moderato [tempo]Popular song [form/genre]Woman leaning on front gate of house [illustration]MWC [graphic artist]Publisher's advertisement on inside front and back cover [note]Companion piece to "in the harbour of home sweet home" [note

Someone is waiting at home sweet home, someone still loves you [first line of chorus]

Performance Medium: Piano, Voice and Chord