Spin 1 inversion: a Majorana tensor force for deuteron alpha scattering

We demonstrate, for the first time, successful S-matrix to potential inversion for spin one projectiles with non-diagonal $S^j_{ll'}$ yielding a $T_{\rm R}$ interaction. The method is a generalization of the iterative-perturbative, IP, method. We present a test case indicating the degree of uniqueness of the potential. The method is adapted, using established procedures, into direct observable to potential inversion, fitting $\sigma$, ${\rm i}T_{11}$, $T_{20}$, $T_{21}$ and $T_{22}$ for d + alpha scattering over a range of energies near 10 MeV. The $T_{\rm R}$ interaction which we find is very different from that proposed elsewhere, both real and imaginary parts being very different for odd and even parity channels.Comment: 7 pages Revtex, 4 ps figure

Investigation of the Coupling Potential by means of S-matrix Inversion

We investigate the inelastic coupling interaction by studying its effect on the elastic scattering potential as determined by inverting the elastic scattering $S$-matrix. We first address the effect upon the real and imaginary elastic potentials of including excited states of the target nucleus. We then investigate the effect of a recently introduced novel coupling potential which has been remarkably successful in reproducing the experimental data for the $^{12}$C+$^{12}$C, $^{12}$C+$^{24}$Mg and $^{16}$O+$^{28}$Si reactions over a wide range of energies. This coupling potential has the effect of deepening the real elastic potential in the surface region, thereby explaining a common feature of many phenomenological potentials. It is suggested that one can relate this deepening to the super-deformed state of the compound nucleus, $^{24}$Mg.Comment: 12 pages with 3 figure

Density waves and supersolidity in rapidly rotating atomic Fermi gases

We study theoretically the low-temperature phases of a two-component atomic Fermi gas with attractive s-wave interactions under conditions of rapid rotation. We find that, in the extreme quantum limit, when all particles occupy the lowest Landau level, the normal state is unstable to the formation of "charge" density wave (CDW) order. At lower rotation rates, when many Landau levels are occupied, we show that the low-temperature phases can be supersolids, involving both CDW and superconducting order.Comment: 4 pages, 1 figure, uses feynmp.st

Hearing the grass grow. Emotional and epistemological challenges of practice-near research

This paper discusses the concept of practice-near research in terms of the emotional and epistemological challenges that arise from the researcher coming 'near' enough to other people for psychological processes to ensue. These may give rise in the researcher to confusion, anxiety and doubt about who is who and what is what; but also to the possibility of real emotional and relational depth in the research process. Using illustrations from three social work doctoral research projects undertaken by students at the Tavistock Clinic and the University of East London the paper examines four themes that seem to the author to be central to meaningful practice-near research undertaken in a spirit of true emotional and epistemological open-mindedness: the smell of the real; losing our minds; the inevitability of personal change; and the discovery of complex particulars

Product renovation and shared ownership: sustainable routes to satisfying the world's growing demand for goods

It has been estimated that by 2030 the number of people who are wealthy enough to be considered as middle class consumers will have tripled. This will have a dramatic impact on the demands for primary materials and energy. Much work has been carried out on sustainable ways of meeting the World’s energy demands and some work has been carried out on the sustainable production and consumption of goods. It has been estimated that with improvements in design and manufacturing it is possible to reduce the primary material requirements by 30% to produce the current demand for goods. Whilst this is a crucial step on the production side, there will still be a doubling of primary material requirements by the end of the century because of an absolute rise in demand for goods and services. It is therefore clear that the consumption of products must also be explored. This is a key areas of research for the UK INDEMAND centre, which is investigating ways of reducing the UK’s industrial energy demand and demand for energy intensive materials. Our ongoing work shows that two strategies would result in considerable reductions in the demand for primary materials: product longevity and using goods more intensively (which may requires increased durability). Product longevity and durability are not new ideas, but ones that can be applied across a raft of goods as methods of reducing the consumption of materials. With long life products there is a potential risk of outdated design and obsolescence, consequently there is a need to ensure upgradability and adaptability are incorporated at the design stage. If products last longer, then the production of new products can be diverted to emerging markets rather than the market for replacement goods. There are many goods which are only used occasionally; these goods do not normally wear out. The total demand for such could be drastically reduced if they were shared with other people. Sharing of goods has traditionally been conducted between friends or by hiring equipment. The use of modern communication systems and social media could enable the development of sharing co-ops and swap spaces that will increase the utilisation of goods and hence reduce the demand for new goods. This could also increase access to a range of goods for those on low incomes. From a series of workshops it has been found that the principal challenges are sociological rather than technological. This paper contains a discussion of these challenges and explores possible futures where these two strategies have been adopted. In addition, the barriers and opportunities that these strategies offer for consumers and businesses are identified, and areas where government policy could be instigated to bring about change are highlighted

Improved dd+4^4He potentials by inversion, the tensor force and validity of the double folding model

Improved potential solutions are presented for the inverse scattering problem for $d$+$^4$He data. The input for the inversions includes both the data of recent phase shift analyses and phase shifts from RGM coupled-channel calculations based on the NN Minnesota force. The combined calculations provide a more reliable estimate of the odd-even splitting of the potentials than previously found, suggesting a rather moderate role for this splitting in deuteron-nucleus scattering generally. The approximate parity-independence of the deuteron optical potentials is shown to arise from the nontrivial interference between antisymmetrization and channel coupling to the deuteron breakup channels. A further comparison of the empirical potentials established here and the double folding potential derived from the M3Y effective NN force (with the appropriate normalisation factor) reveals strong similarities. This result supports the application of the double folding model, combined with a small Majorana component, to the description even of such a loosely bound projectile as the deuteron. In turn, support is given for the application of iterative-perturbative inversion in combination with the double folding model to study fine details of the nucleus-nucleus potential. A $d$-$^4$He tensor potential is also derived to reproduce correctly the negative $^6$Li quadrupole moment and the D-state asymptotic constant.Comment: 22 pages, 12 figures, in Revte

Time evolution of the chiral phase transition during a spherical expansion

We examine the non-equilibrium time evolution of the hadronic plasma produced in a relativistic heavy ion collision, assuming a spherical expansion into the vacuum. We study the $O(4)$ linear sigma model to leading order in a large-$N$ expansion. Starting at a temperature above the phase transition, the system expands and cools, finally settling into the broken symmetry vacuum state. We consider the proper time evolution of the effective pion mass, the order parameter $\langle \sigma \rangle$, and the particle number distribution. We examine several different initial conditions and look for instabilities (exponentially growing long wavelength modes) which can lead to the formation of disoriented chiral condensates (DCCs). We find that instabilities exist for proper times which are less than 3 fm/c. We also show that an experimental signature of domain growth is an increase in the low momentum spectrum of outgoing pions when compared to an expansion in thermal equilibrium. In comparison to particle production during a longitudinal expansion, we find that in a spherical expansion the system reaches the ``out'' regime much faster and more particles get produced. However the size of the unstable region, which is related to the domain size of DCCs, is not enhanced.Comment: REVTex, 20 pages, 8 postscript figures embedded with eps

Isotropic and Anisotropic Regimes of the Field-Dependent Spin Dynamics in Sr2IrO4: Raman Scattering Studies

A major focus of experimental interest in Sr2IrO4 has been to clarify how the magnetic excitations of this strongly spin-orbit coupled system differ from the predictions of anisotropic 2D spin-1/2 Heisenberg model and to explore the extent to which strong spin-orbit coupling affects the magnetic properties of iridates. Here, we present a high-resolution inelastic light (Raman) scattering study of the low energy magnetic excitation spectrum of Sr2IrO4 and doped Eu-doped Sr2IrO4 as functions of both temperature and applied magnetic field. We show that the high-field (H>1.5 T) in-plane spin dynamics of Sr2IrO4 are isotropic and governed by the interplay between the applied field and the small in-plane ferromagnetic spin components induced by the Dzyaloshinskii-Moriya interaction. However, the spin dynamics of Sr2IrO4 at lower fields (H<1.5 T) exhibit important effects associated with interlayer coupling and in-plane anisotropy, including a spin-flop transition at Hc in Sr2IrO4 that occurs either discontinuously or via a continuous rotation of the spins, depending upon the in-plane orientation of the applied field. These results show that in-plane anisotropy and interlayer coupling effects play important roles in the low-field magnetic and dynamical properties of Sr2IrO4.Comment: 8 pages, 4 figures, submitte