Testing Broken U(1) Symmetry in a Two-Component Atomic Bose-Einstein Condensate

We present a scheme for determining if the quantum state of a small trapped Bose-Einstein condensate is a state with well defined number of atoms, a Fock state, or a state with a broken U(1) gauge symmetry, a coherent state. The proposal is based on the observation of Ramsey fringes. The population difference observed in a Ramsey fringe experiment will exhibit collapse and revivals due to the mean-field interactions. The collapse and revival times depend on the relative strength of the mean-field interactions for the two components and the initial quantum state of the condensate.Comment: 20 Pages RevTex, 3 Figure

Mortality post inpatient alcohol detoxification: a descriptive case series

<br>Background: Individuals with alcohol dependence often die prematurely. Scotland in particular has high rates of alcohol misuse compared to the rest of the UK and Europe. Although there is some evidence that rates of alcoholrelated harm and alcohol-related deaths are reducing in Europe, there is little evidence of this trend occurring in Scotland. Inpatient detoxification is an important, but expensive, option in the management of alcohol dependence. Little work has been done with regard possible clinical characteristics associated with mortality post discharge in this cohort of patients.</br> <br>Methods: Retrospective electronic records were used to identify patients admitted electively for alcohol detoxification into a psychiatric ward in a district general hospital under the care of a single consultant addiction psychiatrist between 1/1/05 and 31/12/07 inclusively. Demographic and clinical factors were recorded. 5-year mortality data was obtained by linkage to the National Records of Scotland.</br> <br>Results: 25.2% of patients admitted for elective alcohol detoxification died during the 5-year follow up period. 42.9% of deaths (n=12) were due to alcoholic liver disease, one death (3.6%) was of undetermined intent. A higher proportion of the deceased cohort was likely to have continued disulfiram (93% vs. 80%) and acamprosate (81% vs. 60%) than those surviving. There was no statistically significant difference in survival between individuals on medication and those not on medications in our cohort. The average consumption of units of alcohol per week in the deceased cohort was significantly higher than that calculated for the surviving cohort (298.8 units vs. 233.3 units p=0.0137).</br> <br>Conclusion: Inpatient detoxification was associated with significant mortality at 5-year follow up post- discharge. The majority of deaths were due to liver disease while deaths due to accidents and of undetermined intent were relatively infrequent. Increased education and practical strategies such as “space and pace” aimed both at an individual and societal level to reduce alcohol consumption may help to reduce mortality associated with alcohol dependence post inpatient detoxification.</br&gt

Three-loop corrections to the lightest Higgs scalar boson mass in supersymmetry

I evaluate the largest three-loop corrections to the mass of the lightest Higgs scalar boson in the Minimal Supersymmetric Standard Model in a mass-independent renormalization scheme, using effective field theory and renormalization group methods. The contributions found here are those that depend only on strong and Yukawa interactions and on the leading and next-to-leading logarithms of the ratio of a typical superpartner mass scale to the top quark mass. The approximation assumes that all superpartners and the other Higgs bosons can be treated as much heavier than the top quark, but does not assume their degeneracy. I also discuss the consistent addition of the three-loop corrections to a complete two-loop calculation.Comment: 9 page

Orbiter/launch system

The system includes reusable turbojet propelled booster vehicles releasably connected to a reusable rocket powered orbit vehicle. The coupled orbiter-booster combination takes off horizontally and ascends to staging altitude and speed under booster power with both orbiter and booster wings providing lift. After staging, the booster vehicles fly back to Earth for horizontal landing and the orbiter vehicle continues ascending to orbit

On quantum group symmetry and Bethe ansatz for the asymmetric twin spin chain with integrable boundary

Motivated by a study of the crossing symmetry of the `gemini' representation of the affine Hecke algebra we give a construction for crossing tensor space representations of ordinary Hecke algebras. These representations build solutions to the Yang--Baxter equation satisfying the crossing condition (that is, integrable quantum spin chains). We show that every crossing representation of the Temperley--Lieb algebra appears in this construction, and in particular that this construction builds new representations. We extend these to new representations of the blob algebra, which build new solutions to the Boundary Yang--Baxter equation (i.e. open spin chains with integrable boundary conditions). We prove that the open spin chain Hamiltonian derived from Sklyanin's commuting transfer matrix using such a solution can always be expressed as the representation of an element of the blob algebra, and determine this element. We determine the representation theory (irreducible content) of the new representations and hence show that all such Hamiltonians have the same spectrum up to multiplicity, for any given value of the algebraic boundary parameter. (A corollary is that our models have the same spectrum as the open XXZ chain with nondiagonal boundary -- despite differing from this model in having reference states.) Using this multiplicity data, and other ideas, we investigate the underlying quantum group symmetry of the new Hamiltonians. We derive the form of the spectrum and the Bethe ansatz equations.Comment: 43 pages, multiple figure

Anisotropic Assembly of Colloidal Nanoparticles: Exploiting Substrate Crystallinity

We show that the crystal structure of a substrate can be exploited to drive the anisotropic assembly of colloidal nanoparticles. Pentanethiol-passivated Au particles of approximately 2 nm diameter deposited from toluene onto hydrogen-passivated Si(111) surfaces form linear assemblies (rods) with a narrow width distribution. The rod orientations mirror the substrate symmetry, with a high degree of alignment along principal crystallographic axes of the Si(111) surface. There is a strong preference for anisotropic growth with rod widths substantially more tightly distributed than lengths. Entropic trapping of nanoparticles provides a plausible explanation for the formation of the anisotropic assemblies we observe