Taxing Options: Do Ceos Respond To Favorable Tax Treatment Of Stock Options?

CEO stock option compensation increased tremendously during the 1990s. During this period, the spread between the marginal income and capital gains tax rates increased substantially, creating the potential for tax avoidance. Using ExecuComp data from 1992-2000, we estimate CEOs’ responsiveness to changes in these tax rates. Our findings show that an increase in the marginal income and a decrease in the capital gains tax rate create a significant increase in stock option compensation. Furthermore, the impact of the marginal income tax rate is more than twice that of the capital gains tax rate, which contradicts previous studies.

Erbium dopants in silicon nanophotonic waveguides

The combination of established nanofabrication with attractive material properties makes silicon a promising material for quantum technologies, where implanted dopants serve as qubits with high density and excellent coherence even at elevated temperatures. In order to connect and control these qubits, interfacing them with light in nanophotonic waveguides offers unique promise. Here, we present resonant spectroscopy of implanted erbium dopants in such waveguides. We overcome the requirement of high doping and above-bandgap excitation that limited earlier studies. We thus observe erbium incorporation at well-defined lattice sites with a thousandfold reduced inhomogeneous broadening of about 1 GHz and a spectral diffusion linewidth down to 45 MHz. Our study thus introduces a novel materials platform for the implementation of on-chip quantum memories, microwave-to-optical conversion, and distributed quantum information processing, with the unique feature of operation in the main wavelength band of fiber-optic communication.Comment: 7 pages, 4 figure

Quantum phase transitions to topological Haldane phases in spin-one chains studied by linked-cluster expansions

We use linked-cluster expansions to analyze the quantum phase transitions between symmetry unbroken trivial and topological Haldane phases in two different spin-one chains. The first model is the spin-one Heisenberg chain in the presence of a single-ion anisotropy while the second one is the dimerized spin-one Heisenberg chain. For both models we determine the ground-state energy and the one-particle gap inside the non-topological phase as a high-order series using perturbative continuous unitary transformations. Extrapolations of the gap series are applied to locate the quantum critical point and to extract the associated critical exponent. We find that this approach works unsatisfactory for the anisotropic chain, since the quality of the extrapolation appears insufficient due to the large correlation length exponent. In contrast, extrapolation schemes display very good convergence for the gap closing in the case of the dimerized spin-one Heisenberg chain.Comment: 7 pages, 4 figure

Step Patterns on Vicinal Reconstructed Surfaces

Step patterns on vicinal $(2\times1)$ reconstructed surfaces of noble metals Au(110) and Pt(110), miscut towards the (100) orientation, are investigated. The free energy of the reconstructed surface with a network of crossing opposite steps is calculated in the strong chirality regime when the steps cannot make overhangs. It is explained why the steps are not perpendicular to the direction of the miscut but form in equilibrium a network of crossing steps which make the surface to look like a fish skin. The network formation is the consequence of competition between the -- predominantly elastic -- energy loss and entropy gain. It is in agreement with recent scanning-tunnelling-microscopy observations on vicinal Au(110) and Pt(110) surfaces.Comment: 11 pages with 5 eps figures in text. Uses psfig and elsart.sty (ELSEVIER Science). To be published in Surf. Sc