15,699 research outputs found
Interference of heavy holes in an Aharonov-Bohm ring
We study the coherent transport of heavy holes through a one-dimensional ring
in the presence of spin-orbit coupling. Spin-orbit interaction of holes, cubic
in the in-plane components of momentum, gives rise to an angular momentum
dependent spin texture of the eigenstates and influences transport. We analyze
the dependence of the resulting differential conductance of the ring on hole
polarization of the leads and the signature of the textures in the
Aharonov-Bohm oscillations when the ring is in a perpendicular magnetic field.
We find that the polarization-resolved conductance reveals whether the dominant
spin-orbit coupling is of Dresselhaus or Rashba type, and that the cubic
spin-orbit coupling can be distinguished from the conventional linear coupling
by observing the four-peak structure in the Aharonov-Bohm oscillations.Comment: 12 pages, 11 figure
Real Estate Income and Value Cycles: A Model of Market Dynamics
We develop a theoretical real estate cycles model linking economic fundamentals to real estate income and value. We estimate and test an econometric model specification, based on the theoretical model, using MSA level data for twenty office markets in the United States. Our major conclusion is that cities that exhibit seemingly different cyclical office market behavior may be statistically characterized by our three-parameter econometric specification. The parameters are MSA-specific amplitude, through the CAP rate, cycle duration (peak-to-peak), via the rate of partial adjustments to changing expectations about stabilized NOI and the market trend.
Molecular Mechanics Simulations and Improved Tight-binding Hamiltonians for Artificial Light Harvesting Systems: Predicting Geometric Distributions, Disorder, and Spectroscopy of Chromophores in a Protein Environment
We present molecular mechanics {and spectroscopic} calculations on prototype
artificial light harvesting systems consisting of chromophores attached to a
tobacco mosaic virus (TMV) protein scaffold. These systems have been
synthesized and characterized spectroscopically, but information about the
microscopic configurations and geometry of these TMV-templated chromophore
assemblies is largely unknown. We use a Monte Carlo conformational search
algorithm to determine the preferred positions and orientations of two
chromophores, Coumarin 343 together with its linker, and Oregon Green 488, when
these are attached at two different sites (104 and 123) on the TMV protein. The
resulting geometric information shows that the extent of disorder and
aggregation properties, and therefore the optical properties of the
TMV-templated chromophore assembly, are highly dependent on the choice of
chromophores and protein site to which they are bound. We used the results of
the conformational search as geometric parameters together with an improved
tight-binding Hamiltonian to simulate the linear absorption spectra and compare
with experimental spectral measurements. The ideal dipole approximation to the
Hamiltonian is not valid since the distance between chromophores can be very
small. We found that using the geometries from the conformational search is
necessary to reproduce the features of the experimental spectral peaks
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