Benchmark of a modified Iterated Perturbation Theory approach on the 3d FCC lattice at strong coupling

The Dynamical Mean-Field theory (DMFT) approach to the Hubbard model requires a method to solve the problem of a quantum impurity in a bath of non-interacting electrons. Iterated Perturbation Theory (IPT) has proven its effectiveness as a solver in many cases of interest. Based on general principles and on comparisons with an essentially exact Continuous-Time Quantum Monte Carlo (CTQMC) solver, here we show that the standard implementation of IPT fails away from half-filling when the interaction strength is much larger than the bandwidth. We propose a slight modification to the IPT algorithm that replaces one of the equations by the requirement that double occupancy calculated with IPT gives the correct value. We call this method IPT-$D$. We recover the Fermi liquid ground state away from half-filling. The Fermi liquid parameters, density of states, chemical potential, energy and specific heat on the FCC lattice are calculated with both IPT-$D$ and CTQMC as benchmark examples. We also calculated the resistivity and the optical conductivity within IPT-$D$. Particle-hole asymmetry persists even at coupling twice the bandwidth. Several algorithms that speed up the calculations are described in appendices.Comment: 17 pages, 15 figures, minor changes to improve clarit

Evaluation and Management of Sleep Disorders in the Hand Surgery Patient.

Despite posing a significant public health threat, sleep disorders remain poorly understood and often underdiagnosed and mismanaged. Although sleep disorders are seemingly unrelated, hand surgeons should be mindful of these because numerous conditions of the upper extremity have known associations with sleep disturbances that can adversely affect patient function and satisfaction. In addition, patients with sleep disorders are at significantly higher risk for severe, even life-threatening medical comorbidities, further amplifying the role of hand surgeons in the recognition of this condition

A Resource-Based View Of International Human Resources: Toward A Framework of Integrative and Creative Capabilities

Drawing on organizational learning and MNC perspectives, we extend the resource-based view to address how international human resource management provides sustainable competitive advantage. We develop a framework that emphasizes and extends traditional assumptions of the resource-based view by identifying the learning capabilities necessary for a complex and changing global environment. These capabilities address how MNCs might both create new HR practices in response to local environments and integrate existing HR practices from other parts of the firm (affiliates, regional headquarters, and global headquarters). In an effort to understand the nature of such capabilities, we discuss aspects of human capital, social capital, and organizational capital that might be linked to their development. Page

Constraints on the Velocity and Spatial Distribution of Helium-like Ions in the Wind of SMC X-1 from Observations with XMM-Newton/RGS

We present here X-ray spectra of the HMXB SMC X-1 obtained in an observation with the XMM observatory beginning before eclipse and ending near the end of eclipse. With the Reflection Grating Spectrometers (RGS) on board XMM, we observe emission lines from hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon. Though the resolution of the RGS is sufficient to resolve the helium-like n=2->1 emission into three line components, only one of these components, the intercombination line, is detected in our data. The lack of flux in the forbidden lines of the helium-like triplets is explained by pumping by ultraviolet photons from the B0 star and, from this, we set an upper limit on the distance of the emitting ions from the star. The lack of observable flux in the resonance lines of the helium-like triplets indicate a lack of enhancement due to resonance line scattering and, from this, we derive a new observational constraint on the distribution of the wind in SMC X-1 in velocity and coordinate space. We find that the solid angle subtended by the volume containing the helium-like ions at the neutron star multiplied by the velocity dispersion of the helium-like ions must be less than 4pi steradians km/s. This constraint will be satisfied if the helium-like ions are located primarily in clumps distributed throughout the wind or in a thin layer along the surface of the B0 star.Comment: 22 pages, 17 figures, ApJ accepted, discussion of relevant other work adde

Differential Emission Measure Determination of Collisionally Ionized Plasma: II. Application to Hot Stars

In a previous paper we have described a technique to derive constraints on the differential emission measure (DEM) distribution, a measure of the temperature distribution, of collisionally ionized hot plasmas from their X-ray emission line spectra. We apply this technique to the Chandra/HETG spectra of all of the nine hot stars available to us at the time this project was initiated. We find that DEM distributions of six of the seven O stars in our sample are very similar but that theta Ori has an X-ray spectrum characterized by higher temperatures. The DEM distributions of both of B stars in our sample have lower magnitudes than those of the O stars and one, tau Sco, is characterized by higher temperatures than the other, beta Cru. These results confirm previous work in which high temperatures have been found for theta Ori and tau Sco and taken as evidence for channeling of the wind in magnetic fields, the existence of which are related to the stars' youth. Our results demonstrate the utility of our method for deriving temperature information for large samples of X-ray emission line spectra.Comment: The contents of this paper were formerly part of astro-ph/0403603 which was split into two paper

MECHANICAL DAMPING SYSTEM FOR STRUCTURES

A mechanical damping system for a structure is provided. The mechanical damping system comprises a tubular impact frame secured to the structure. A support frame is secured to the structure with the support frame spaced from the impact frame. An elongated member is provided having a first end and a second end. The first end is secured within the support frame and the second end is free from connection and extends into the impact frame. At least one impact mass is secured to the second end of the elongated member, the impact mass movable within and contactable with the impact frame

Superdense coding of quantum states

We describe a method to non-obliviously communicate a 2l-qubit quantum state by physically transmitting l+o(l) qubits of communication, and by consuming l ebits of entanglement and some shared random bits. In the non-oblivious scenario, the sender has a classical description of the state to be communicated. Our method can be used to communicate states that are pure or entangled with the sender's system; l+o(l) and 3l+o(l) shared random bits are sufficient respectively.Comment: 5 pages, revtex