Delocalized Entanglement of Atoms in optical Lattices

We show how to detect and quantify entanglement of atoms in optical lattices in terms of correlations functions of the momentum distribution. These distributions can be measured directly in the experiments. We introduce two kinds of entanglement measures related to the position and the spin of the atoms

On the Azimuthal Stability of Shock Waves around Black Holes

Analytical studies and numerical simulations of time dependent axially symmetric flows onto black holes have shown that it is possible to produce stationary shock waves with a stable position both for ideal inviscid and for moderately viscous accretion disks. We perform several two dimensional numerical simulations of accretion flows in the equatorial plane to study shock stability against non-axisymmetric azimuthal perturbations. We find a peculiar new result. A very small perturbation seems to produce an instability as it crosses the shock, but after some small oscillations, the shock wave suddenly transforms into an asymmetric closed pattern, and it stabilizes with a finite radial extent, despite the inflow and outflow boundary conditions are perfectly symmetric. The main characteristics of the final flow are: 1) The deformed shock rotates steadily without any damping. It is a permanent feature and the thermal energy content and the emitted energy vary periodically with time. 2) This behavior is also stable against further perturbations. 3) The average shock is still very strong and well defined, and its average radial distance is somewhat larger than that of the original axially symmetric circular shock. 4) Shocks obtained with larger angular momentum exhibit more frequencies and beating phenomena. 5) The oscillations occur in a wide range of parameters, so this new effect may have relevant observational consequences, like (quasi) periodic oscillations, for the accretion of matter onto black holes. Typical time scales for the periods are 0.01 and 1000 seconds for black holes with 10 and 1 million solar mass, respectively.Comment: 15 pages, 7 figures, accepted by the Astrophysical Journa

Lattice QCD at non-vanishing density: phase diagram, equation of state

We propose a method to study lattice QCD at non-vanishing temperature (T) and chemical potential (\mu). We use n_f=2+1 dynamical staggered quarks with semi-realistic masses on L_t=4 lattices. The critical endpoint (E) of QCD on the Re(\mu)-T plane is located. We calculate the pressure (p), the energy density (\epsilon) and the baryon density (n_B) of QCD at non-vanishing T and \mu.Comment: Contributed to Workshop on Strong and Electroweak Matter (SEWM 2002), Heidelberg, Germany, 2-5 Oct 200

Effective pre-school, primary and secondary education project (EPPSE 3-14): students’ reports of their experiences of school in Year 9

The Effective Pre-school, Primary and Secondary Education Project (EPPSE) has inves tigated the academic and social behavioural (+ in the later stages the affective) development of approximately 3,000 children from the age of 3+ years since 1997. This report presents the results of analyses related to student’s experiences in Year 9 (age 14), with the purpose of creating measures of both school and classroom life as experienced by students. These measures have been used in the analysis of academic and social-behavioural outcomes as well as dispositions to investigate whether a student’s reported experience of school can significantly predict outcomes in other areas. The findings highlight the importance of the ‘student voice’ and provide an insight into the experiences of teenagers in the first decade of the 21st Century

Influences on students’ attainment and progress in Key Stage 3: academic outcomes in English, Maths and Science in Year 9

The Effective Pre-school, Primary and Secondary Education Project (EPPSE) has investigated the academic and social-behavioural development of approximately 3,000 children from the age of 3+ years since 1997. This Research Brief focuses on the relationships between a range of individual student, family, home, pre-, primary and secondary school characteristics and students\u27 academic attainment in English, maths and science in Year 9 at secondary school (age 14). It compares the latest findings with those found for students\u27 attainment at younger ages. It also highlights the influences of secondary school on students\u27 attainment in the core curriculum areas and studies their academic progress across Key Stage 3 between the ages of 11 and 14

Cubic interaction parameters for t2g Wannier orbitals

Many-body calculations for multi-orbital systems at present typically employ Slater or Kanamori interactions which implicitly assume a full rotational invariance of the orbitals, whereas the real crystal has a lower symmetry. In cubic symmetry, the low-energy $t_{2g}$ orbitals have an on-site Kanamori interaction, albeit without the constraint $U = U' + 2J$ implied by spherical symmetry ($U$: intra-orbital interaction, $U'$: inter-orbital interaction, $J$: Hund's exchange). Using maximally localized Wannier functions we show that deviations from the standard, spherically symmetric interactions are indeed significant for $5d$ orbitals ($\sim25$ for BaOsO$_3$ ; $\sim12$ if screening is included), but less important for $3d$ orbitals ($\sim6\%$ for SrVO$_3$; $\sim1\%$ if screened).Comment: 9 pages, 3 figures, 6 tables; as publishe

Two point correlations of a trapped interacting Bose gas at finite temperature

We develop a computationally tractable method for calculating correlation functions of the finite temperature trapped Bose gas that includes the effects of s-wave interactions. Our approach uses a classical field method to model the low energy modes and treats the high energy modes using a Hartree-Fock description. We present results of first and second order correlation functions, in position and momentum space, for an experimentally realistic system in the temperature range of $0.6T_c$ to $1.0T_c$. We also characterize the spatial coherence length of the system. Our theory should be applicable in the critical region where experiments are now able to measure first and second order correlations.Comment: 9 pages, 4 figure

High temperature /800 to 1600 F/ magnetic materials

Tests of magnetic materials from 800 to 1600