Gravity, Two Times, Tractors, Weyl Invariance and Six Dimensional Quantum Mechanics

Fefferman and Graham showed some time ago that four dimensional conformal geometries could be analyzed in terms of six dimensional, ambient, Riemannian geometries admitting a closed homothety. Recently it was shown how conformal geometry provides a description of physics manifestly invariant under local choices of unit systems. Strikingly, Einstein's equations are then equivalent to the existence of a parallel scale tractor (a six component vector subject to a certain first order covariant constancy condition at every point in four dimensional spacetime). These results suggest a six dimensional description of four dimensional physics, a viewpoint promulgated by the two times physics program of Bars. The Fefferman--Graham construction relies on a triplet of operators corresponding, respectively to a curved six dimensional light cone, the dilation generator and the Laplacian. These form an sp(2) algebra which Bars employs as a first class algebra of constraints in a six-dimensional gauge theory. In this article four dimensional gravity is recast in terms of six dimensional quantum mechanics by melding the two times and tractor approaches. This "parent" formulation of gravity is built from an infinite set of six dimensional fields. Successively integrating out these fields yields various novel descriptions of gravity including a new four dimensional one built from a scalar doublet, a tractor vector multiplet and a conformal class of metrics.Comment: 27 pages, LaTe

Zirconium trisulfide as a promising cathode material for Li primary thermal batteries

In this work ZrS3 has been synthesized by solid state reaction in a sealed quartz tube and investigated as a candidate cathode material in Li thermal batteries. The structure of ZrS3 before and after cell testing has been studied using powder X-ray diffraction. A new spinel related material, LiZr2S4, has been identified as the product of the electrochemical process, which can be indexed to a = 10.452(8) Å cubic unit cell. The electrochemical properties of the batteries were investigated at 500 °C against Li13Si4 by galvanostatic discharge and galvanostatic intermittent titration technique (GITT). In a thermal Li cell at 500 °C a single voltage plateau of 1.70 V at a current density of 11 mA/cm2 was achieved with capacity of 357 mA h g-1. Therefore ZrS3 material has some promise as a cathode for Li thermal batteries.Publisher PDFPeer reviewe

Non-linear Realizations of Conformal Symmetry and Effective Field Theory for the Pseudo-Conformal Universe

The pseudo-conformal scenario is an alternative to inflation in which the early universe is described by an approximate conformal field theory on flat, Minkowski space. Some fields acquire a time-dependent expectation value, which breaks the flat space so(4,2) conformal algebra to its so(4,1) de Sitter subalgebra. As a result, weight-0 fields acquire a scale invariant spectrum of perturbations. The scenario is very general, and its essential features are determined by the symmetry breaking pattern, irrespective of the details of the underlying microphysics. In this paper, we apply the well-known coset technique to derive the most general effective lagrangian describing the Goldstone field and matter fields, consistent with the assumed symmetries. The resulting action captures the low energy dynamics of any pseudo-conformal realization, including the U(1)-invariant quartic model and the Galilean Genesis scenario. We also derive this lagrangian using an alternative method of curvature invariants, consisting of writing down geometric scalars in terms of the conformal mode. Using this general effective action, we compute the two-point function for the Goldstone and a fiducial weight-0 field, as well as some sample three-point functions involving these fields.Comment: 49 pages. v2: minor corrections, added references. v3: minor edits, version appearing in JCA

Transition metal chlorides NiCl2, KNiCl3, Li6VCl8 and Li2MnCl4 as alternative cathode materials in primary Li thermal batteries

Special thanks to AWE Plc for their support and funding for this work. The authors would also like to acknowledge the EPSRC Platform Grant EP/K015540/1 and the Royal Society Wolfson Merit Award WRMA 2012/R2.Transition metal chlorides KNiCl3, Li6VCl8 and Li2MnCl4 were synthesized by solid state reaction in sealed quartz tubes and investigated as candidate cathode materials along with NiCl2 in Li thermal batteries. The structure and morphology were studied and electrochemical properties probed at high temperatures (400°C–500°C) against Li13Si4 by galvanostatic discharge and galvanostatic intermittent titration technique (GITT). All the transition metal chlorides reduced to metal and the products of the discharge mechanism were confirmed by powder X-ray diffraction. NiCl2 was tested at 500°C and a capacity of 360 mAhg−1 was achieved. KNiCl3 was tested at different current densities from 15 mA/cm2 to 75 mA/cm2 and a high voltage profile 2.30V was achieved at 425°C with a capacity of 262 mAhg−1. Li6VCl8 was tested at 500°C and a 1.80V voltage plateau at a current density of 7.5 mA/cm2 was achieved with a capacity of 145 mAhg−1. Li2MnCl4 was tested at the same current density at 400°C and a capacity of 254 mAhg−1 was achieved. These transition metal chlorides exhibit higher voltage against Li13Si4 and, hence, provide more specific power compared to the well-known metal disulfides MS2 (M = Fe, Co, Ni) and may be promising cathode materials for Li thermal batteries.Publisher PDFPeer reviewe

Notes on the ambient approach to boundary values of AdS gauge fields

The ambient space of dimension d+2 allows to formulate both fields on AdS(d+1) and conformal fields in d dimensions such that the symmetry algebra o(d,2) is realized linearly. We elaborate an ambient approach to the boundary analysis of gauge fields on anti de Sitter spacetime. More technically, we use its parent extension where fields are still defined on AdS or conformal space through arbitrary intrinsic coordinates while the ambient construction works in the target space. In this way, a manifestly local and o(d,2)-covariant formulation of the boundary behaviour of massless symmetric tensor gauge fields on AdS(d+1) spacetime is obtained. As a byproduct, we identify some useful ambient formulation for Fronsdal fields, conformal currents and shadow fields along with a concise generating-function formulation of the Fradkin-Tseytlin conformal fields somewhat similar to the one obtained by Metsaev. We also show how this approach extends to more general gauge theories and discuss its relation to the unfolded derivation of the boundary dynamics recently proposed by Vasiliev.Comment: Slightly expanded version of the invited contribution to the J.Phys.A special volume on "Higher Spin Theories and AdS/CFT" edited by Matthias Gaberdiel and Mikhail Vasiliev; version 2: addition of 2 references, some comparisons with the standard AdS/CFT framework and comments on the scalar singleton cas

Beta-gamma systems and the deformations of the BRST operator

We describe the relation between simple logarithmic CFTs associated with closed and open strings, and their "infinite metric" limits, corresponding to the beta-gamma systems. This relation is studied on the level of the BRST complex: we show that the consideration of metric as a perturbation leads to a certain deformation of the algebraic operations of the Lian-Zuckerman type on the vertex algebra, associated with the beta-gamma systems. The Maurer-Cartan equations corresponding to this deformed structure in the quasiclassical approximation lead to the nonlinear field equations. As an explicit example, we demonstrate, that using this construction, Yang-Mills equations can be derived. This gives rise to a nontrivial relation between the Courant-Dorfman algebroid and homotopy algebras emerging from the gauge theory. We also discuss possible algebraic approach to the study of beta-functions in sigma-models.Comment: LaTeX2e, 15 pages; minor revision, typos corrected, Journal of Physics A, in pres

In-situ studies of high temperature thermal batteries : a perspective

Funding: UK Engineering and Physical Sciences Research Council (EP/P007821/1).Here we present a perspective on in-situ studies of high temperature batteries. We focus on a primary battery technology- the thermal battery- which possesses a molten salt electrolyte. We discuss aspects of sample environment design, data collection and will briefly look at some case studies. We aim to highlight the importance of using in-situ techniques in studying electrochemical devices such as high temperature batteries.Publisher PDFPeer reviewe

Outside the gate: sub-urban legal practices in early medieval England

Many aspects of English early medieval (Anglo-Saxon) legal landscapes can be discerned in archaeological and toponymic evidence, ranging from the locations of legislative councils and judicial assemblies to sites of capital punishment. Among the corpus of such sites a striking group can be detected at the periphery of urban spaces. Gates into a number of towns appear to have functioned as legislative meeting-places, and even gave their names to some legally constituted communities, while suburban locations also feature prominently as sites of gallows and public punishment. In this paper historical, archaeological and toponymic evidence is used to examine this phenomenon of suburban legal practices and to pose questions about the wider dimensions of the early medieval legal landscape

Reconsidering the Tribal-State Compact Process

This essay evaluates the tribal‐state compact process, as one of several alternative, nonadversarial processes, warranting attention. It argues that, because of its binding character and relatively low cost (in contrast to litigation), and because it is based in the idea of tribes and states exhibiting mutual respect, the compact process is an advanced version of negotiation and bargaining that tribes and states should consider where appropriate

Increased indoleamine-2,3-dioxygenase activity is associated with poor clinical outcome in adults hospitalized with influenza in the INSIGHT FLU003Plus study

BACKGROUND: Indoleamine-2,3-dioxygenase (IDO) mediated tryptophan (TRP) depletion has antimicrobial and immuno-regulatory effects. Increased kynurenine (KYN)-to-TRP (KT) ratios, reflecting increased IDO activity, have been associated with poorer outcomes from several infections. METHODS: We performed a case-control (1:2; age and sex matched) analysis of adults hospitalized with influenza A(H1N1)pdm09 with protocol-defined disease progression (died/transferred to ICU/mechanical ventilation) after enrollment (cases) or survived without progression (controls) over 60 days of follow-up. Conditional logistic regression was used to analyze the relationship between baseline KT ratio and other metabolites and disease progression. RESULTS: We included 32 cases and 64 controls with a median age of 52 years; 41% were female, and the median durations of influenza symptoms prior to hospitalization were 8 and 6 days for cases and controls, respectively (P = .04). Median baseline KT ratios were 2-fold higher in cases (0.24 mM/M; IQR, 0.13-0.40) than controls (0.12; IQR, 0.09-0.17; P ≤ .001). When divided into tertiles, 59% of cases vs 20% of controls had KT ratios in the highest tertile (0.21-0.84 mM/M). When adjusted for symptom duration, the odds ratio for disease progression for those in the highest vs lowest tertiles of KT ratio was 9.94 (95% CI, 2.25-43.90). CONCLUSIONS: High KT ratio was associated with poor outcome in adults hospitalized with influenza A(H1N1)pdm09. The clinical utility of this biomarker in this setting merits further exploration. CLINICALTRIALSGOV IDENTIFIER: NCT01056185