τ e , τ h electron & hole minority carrier lifetimes respectively L e , L h electron & hole minority carrier diffusion lengths respectively µ e , µ h electron & hole mobilities respectively (cm 2 /V-sec) D e , D h electron & hole diffusivities respectively (cm 2 /sec) n e , n h the electron & hole concentrations respectively n e0 , n h0 electron & hole concentrations in thermal equilibrium n i ...

Ž . The local spin density LSD approximation, while of only moderate accuracy, has proven extremely reliable over three decades of use. We argue that any gradient-corrected functional should preserve the correct features of LSD, even if the system under study Ž . contains no regions of small density gradient. The Perdew]Wang 1991 PW91 functional Ž . respects this condition, while, e.g., the Lee...

Employing Big Bear Solar Observatory (BBSO) deep magnetograms and Hα images in a quiet region and a coronal hole, observed on September 14 and 16, 2004, respectively, we have explored the magnetic flux emergence, disappearance and distribution in the two regions. The following results are obtained: (1) The evolution of magnetic flux in the quiet region is much faster than that in the coronal ho...

A systematic study of the hole mobility in hole-only diodes and field-effect transistors based on poly(2-methoxy-5-(3('),7(')-dimethyloctyloxy)-p-phenylene vinylene) and on amorphous poly(3-hexyl thiophene) has been performed as a function of temperature and applied bias. The experimental hole mobilities extracted from both types of devices, although based on a single polymeric semiconductor, c...

With the recent discovery of very long hole spin decoherence times in GaAs/AlGaAs heterostructures of more than 70 ns in two-dimensional hole systems, using the hole spin as a viable alternative to electron spins in spintronic applications seems possible. Furthermore, as the hyperfine interaction with the nuclear spins is likely to be the limiting factor for electron spin lifetimes in zero dime...

We have studied the time evolution of the power spectrum of XTE J1550-564, using X-ray luminosity time series data obtained by the Rossi X-Ray Timing Explorer satellite. A number of important practical fundamental issues arise in the analysis of these data, including dealing with time-tagged event data, removal of noise from a highly non stationary signal, and comparison of different time-frequ...

The merger of two supermassive black holes is expected to produce a gravitational-wave signal detectable by the satellite LISA. The rate of supermassive-black-hole mergers is intimately connected to the halo merger rate, and the extended Press–Schechter formalism is often employed when calculating the rate at which these events will be observed by LISA. This merger theory is flawed and provides...

We present a numerical study of the effects of carrier diffusion and spatial hole-burning in vertical-cavity surfaceemitting lasers under gain switching. Our model includes spatial and temporal dependences of both the optical field and the carrier density. Results show that spatial hole burning places a limit on the minimum achievable pulse width. We demonstrate that spatial hole-burning can be...

The coherent evolution of an electron hole in a photoionized molecule represents an unexplored facet of charge transfer phenomena occurring in complex systems. Using ultrafast extreme ultraviolet spectroscopy, we investigate the real-time dynamics of an electron hole wave packet created near a conical intersection in CO_{2}. We resolve the oscillation of the electron hole density between σ and ...

First results of a numerical investigation of primordial black hole formation in the radiation dominated phase of the Early Universe are presented. The simulations follow the gravitational collapse of three different families of high-amplitude density fluctuations imposed at the time of horizon crossing. The threshold for black hole formation, δc ≈ 0.7, is found to be nearly identical for all p...