A new proof of a theorem of Magidor

We give a new proof using iterated Prikry forcing of Magidor's theorem that it is consistent to assume that the least strongly compact cardinal is the least supercompact cardinal. Received: 8 December 1997 / Revised version: 12 November 1998     

Modeling Ergodic, Measure Preserving Actionson Shifts of Finite Type

 In this paper we show that shifts of finite type satisfying a strong topological mixing property are universal models for ergodic measure preserving dynamical systems.     

Output voltage calculations in double barrier magnetic tunnel junctions with asymmetric voltage behavior

In this paper we study the asymmetric voltage behavior (AVB) of the tunnel magnetoresistance (TMR) for single and double barrier magnetic tunnel junctions (MTJs) in range of a quasi-classical free electron model. Numerical calculations of the TMR–V curves, output voltages and I–V characteristics for negative and positive values of applied voltages were carried out using MTJs with CoFeB/MgO interfaces as an example. Asymmetry of the experimental TMR–V curves is explained by different values of the minority and majority Fermi wave vectors for the left and right sides of the tunnel barrier, which arises due to different annealing regimes. Electron tunneling in DMTJs was simulated in two ways: (i) Coherent tunneling, where the DMTJ is modeled as one tunnel system and (ii) consecutive tunneling, where the DMTJ is modeled by two single barrier junctions connected in series.     

Complex classical fields: An example

We study complex, classical, scalar fields within a new framework introduced in a previous work. We replace the usual functional integral by a complex functional arising from a boosted Hamiltonian. We generalize the Feynman–Kac relation to this setting, and use it to establish the spectral condition on a cylinder. We consider also positive-temperature states.     

Higher-order accurate polyspectral estimation with flat-top lag-windows

Improved performance in higher-order spectral density estimation is achieved using a general class of infinite-order kernels. These estimates are asymptotically less biased but with the same order of variance as compared to the classical estimators with second-order kernels. A simple, data-dependent algorithm for selecting the bandwidth is introduced and is shown to be consistent with estimating the optimal bandwidth. The combination of the specialized family of kernels with the new bandwidth selection algorithm yields a considerably improved polyspectral estimator surpassing the performances of existing estimators using second-order kernels. Bispectral simulations with several standard models are used to demonstrate the enhanced performance with the proposed methodology.     

Tailoring terahertz near-field enhancement via two-dimensional plasmons

We suggest a novel possibility for electrically tunable terahertz near-field enhancement in flatland electronic materials supporting two-dimensional plasmons, including recently discovered graphene. We employ electric-field effect modulation of electron density in such materials and induce a periodic plasmonic lattice with a defect cavity. We demonstrate that the plasmons resonantly excited in such a periodic plasmonic lattice by an incident terahertz radiation can strongly pump the cavity plasmon modes leading to a deep subwavelength concentration of terahertz energy, beyond λ/1000, with giant electric-field enhancement factors up to 10(4), which is 2 orders of magnitude higher than achieved previously in metal-based terahertz field concentrators.     

Model for diffusion-limited electrochemiluminescence

An approximate analytic expression is derived, based on a novel model for the reactive–diffusive processes in a electrochemiluminescence (ecl) experiment. The physical system treated is one in which ecl is produced by stepping the voltage of a planar electrode to the diffusion-limited reduction value for an emitter species in the presence of a bulk oxidant precursor (9,10-DPA with benzoyl peroxide). The unknown rate constants are determined by a least-squares curve-fitting computer code. The model, though crude, provides an excellent fit to the ecl intensity versus time data, including the rise portion of the curve.     

2-(3,5-Dinitrophenyl)-1,3-dithiane carbanion: a benzylic anion with a low energy triplet state

Calculations at the DFT level predict that benzyl anions with strong π-electron-withdrawing groups in the meta position(s) have low energy diradical or triplet electronic states. Specifically, the 2-(3,5-dinitrophenyl)-1,3-dithiane carbanion is predicted to have nearly degenerate singlet and triplet states at the (U)B3LYP level as a free anion. Its lithium ion pair is predicted to be a ground-state triplet with a substantial (26 kcal/mol) singlet-triplet energy gap. Experiments on this anion using chemical trapping, NMR, and the Evans method strongly suggest that this anion is either a triplet or a ground-state singlet with a very low energy triplet state.