A reduced coupled-mode description for the electron-ion energy relaxation in dense matter

We present a simplified model for the electron-ion energy relaxation in dense two-temperature systems that includes the effects of coupled collective modes. It also extends the standard Spitzer result to both degenerate and strongly coupled systems. Starting from the general coupled-mode description, we are able to solve analytically for the temperature relaxation time in warm dense matter and strongly coupled plasmas. This was achieved by decoupling the electron-ion dynamics and by representing the ion response in terms of the mode frequencies. The presented reduced model allows for a fast description of temperature equilibration within hydrodynamic simulations and an easy comparison for experimental investigations. For warm dense matter, both fluid and solid, the model gives a slower electron-ion equilibration than predicted by the classical Spitzer result

Ultracold Atoms as a Target: Absolute Scattering Cross-Section Measurements

We report on a new experimental platform for the measurement of absolute scattering cross-sections. The target atoms are trapped in an optical dipole trap and are exposed to an incident particle beam. The exponential decay of the atom number directly yields the absolute total scattering cross-section. The technique can be applied to any atomic or molecular species that can be prepared in an optical dipole trap and provides a large variety of possible scattering scenarios

Adiabatic loading of a Bose-Einstein condensate in a 3D optical lattice

We experimentally investigate the adiabatic loading of a Bose-Einstein condensate into an optical lattice potential. The generation of excitations during the ramp is detected by a corresponding decrease in the visibility of the interference pattern observed after free expansion of the cloud. We focus on the superfluid regime, where we show that the limiting time scale is related to the redistribution of atoms across the lattice by single-particle tunneling

Fast nonadiabatic dynamics of many-body quantum systems

Modeling many-body quantum systems with strong interactions is one of the core challenges of modern physics. A range of methods has been developed to approach this task, each with its own idiosyncrasies, approximations, and realm of applicability. However, there remain many problems that are intractable for existing methods. In particular, many approaches face a huge computational barrier when modeling large numbers of coupled electrons and ions at finite temperature. Here, we address this shortfall with a new approach to modeling many-body quantum systems. On the basis of the Bohmian trajectory formalism, our new method treats the full particle dynamics with a considerable increase in computational speed. As a result, we are able to perform large-scale simulations of coupled electron-ion systems without using the adiabatic Born-Oppenheimer approximation

All-optical formation of a Bose-Einstein condensate for applications in scanning electron microscopy

We report on the production of a F=1 spinor condensate of 87Rb atoms in a single beam optical dipole trap formed by a focused CO2 laser. The condensate is produced 13mm below the tip of a scanning electron microscope employing standard all-optical techniques. The condensate fraction contains up to 100,000 atoms and we achieve a duty cycle of less than 10s.Comment: 5 pages, 4 figure

Probing the hydrogen melting line at high pressures by dynamic compression

We investigate the capabilities of dynamic compression by intense heavy ion beams to yield information about the high pressure phases of hydrogen. Employing ab initio simulations and experimental data, a new wide range equation of state for hydrogen is constructed. The results show that the melting line up to its maximum as well as the transition from molecular fluids to fully ionized plasmas can be tested with the beam parameters soon to be available. We demonstrate that x-ray scattering can distinguish between phases and dissociation states

Has incentive payment improved venous thrombo-embolism risk assessment and treatment of hospital in-patients?

This paper focuses on financial incentives rewarding successful implementation of guidelines in the UK National Health Service (NHS). In particular, it assesses the implementation of National Institute for Health and Clinical Excellence (NICE) venous thrombo-embolism (VTE) guidance in 2010 on the risk assessment and secondary prevention of VTE in hospital in-patients and the financial incentives driving successful implementation introduced by the Commissioning for Quality and Innovation for Payment Framework (CQUIN) for 2010-2011. We systematically compared the implementation of evidence-based national guidance on VTE prevention across two specialities (general medicine and orthopaedics) in four hospital sites in the greater South West of England by auditing and evaluating VTE prevention activity for 2009 (i.e. before the 2010 NICE guideline) and late 2010 (almost a year after the guideline was published). Analysis of VTE prevention activity reported in 816 randomly selected orthopaedic and general medical in-patient medical records was complemented by a qualitative study into the practical responses to revised national guidance. This paper's contribution to knowledge is to suggest that by financially rewarding the implementation of national guidance on VTE prevention, paradoxes and contradictions have become apparent between the 'payment by volume system' of Healthcare Resource Groups and the 'payment by results' system of CQUIN

Emergence and the human genome

Peer reviewedThe (human) genome functions as an open system within human nutritional, economic, cultural, intellectual and emotional contexts. Of profound importance is the extent of free will that emerged with our cognitive and consciousness traits. We have been instrumental in creating particular environments and semiotics according to which we live and with which our genes are expressed. The possibility exists that an information continuum between genes, brain and environment may follow quantum rules and exhibit correlated properties that result in coordinated behaviour (entanglement), even without signal transfer or interaction. With the unprecedented technological advances made during the last century, for the first time a biological organism can, in theory, purposefully design its own future evolution. This is likely to remain limited by ultimate unpredictability due to emergent novelties arising during the process. The effect(s) of a strong human strategic guiding influence, however, implies a tremendous moral responsibility to help shape future outcomes which will enhance the continued existence of quality Life on Earth. How are we doing so far, and how can we exploit knowledge of the possible structural basis of genomic memory and the principles linked with self organisation and emergence to avoid recurrence of outcomes previously shown to have had negative consequences for Life. Can we feed back crucial brain memories to the germline contrary to prevailing dogma, and does this contribute to a compound interest situation not only of intellectual ability but also of a hereditary basis for augmenting ("negative", Machiavellian type) moral behaviour previously found to be successful for pure biological survival?Research Institute for Theology and Religio

An adaptive model for the optical properties of excited gold

We study the temperature-dependent optical properties of gold over a broad energy spectrum covering photon energies below and above the interband threshold. We apply a semi-analytical Drude-Lorentz model with temperature-dependent oscillator parameters. Our approximations are based on the distribution of electrons over the active bands with a density of states provided by density functional theory. This model can be easily adapted to other materials with similar band structures and can also be applied to the case of occupational nonequilibrium. Our calculations show a strong enhancement of the intraband response with increasing electron temperature while the interband component decreases. Moreover, our model compares well with density functional theory-based calculations for the reflectivity of highly excited gold and reproduces many of its key features. Applying our methods to thin films shows a sensitive nonlinear dependence of the reflection and absorption on the electron temperature. These features are more prominent at small photon energies and can be highlighted with polarized light. Our findings offer valuable insights for modeling ultrafast processes, in particular, the pathways of energy deposition in laser-excited samples