Generalized Supersymmetries and Composite Structure in M-Theory

We describe generalized D=11 Poincar\'{e} and conformal supersymmetries. The corresponding generalization of twistor and supertwistor framework is outlined with $OSp(1|64)$ superspinors describing BPS preons. The $\frac{k}{32}$ BPS states as composed out of $n=32 - k$ preons are introduced, and basic ideas concerning BPS preon dynamics is presented. The lecture is based on results obtained by J.A. de Azcarraga, I. Bandos, J.M. Izquierdo and the author$^1$.Comment: LaTeX, 7pages. Talk presented at the XVI-th Max Born Symposium ,,Supersymmetries and Quantum Symmetries `01" (21-25.09.2001, Karpacz, Poland) and International Nankai Symposium (8-11.10.2001, Tianjin, China). To be published in the Proceedings of Nankai Symposium, Ed. Ge Mo-Lin and J. Park, Int. J. Mod. Phys.

Hamiltonian analysis of Poincar\'e gauge theory scalar modes

The Hamiltonian constraint formalism is used to obtain the first explicit complete analysis of non-trivial viable dynamic modes for the Poincar\'e gauge theory of gravity. Two modes with propagating spin-zero torsion are analyzed. The explicit form of the Hamiltonian is presented. All constraints are obtained and classified. The Lagrange multipliers are derived. It is shown that a massive spin-$0^-$ mode has normal dynamical propagation but the associated massless $0^-$ is pure gauge. The spin-$0^+$ mode investigated here is also viable in general. Both modes exhibit a simple type of ``constraint bifurcation'' for certain special field/parameter values.Comment: 28 pages, LaTex, submitted to International Journal of Modern Physics

Difference in general practice telehealth utilisation associated with birth country during COVID-19 from two Australian states

Objective: Telehealth has been an integral part of ensuring continued general practice access during the COVID-19 pandemic. Whether telehealth was similarly adopted across different ethnic, cultural, and linguistic groups in Australia is unknown. In this study, we assessed how telehealth utilisation differed by birth country. Methods: In this retrospective observational study, electronic health record data from 799 general practices across Victoria and New South Wales, Australia between March 2020 to November 2021 were extracted (12,403,592 encounters from 1,307,192 patients). Multivariate generalised estimating equation models were used to assess the likelihood of a telehealth consultation (against face-to-face consultation) by birth country (relative to Australia or New Zealand born patients), education index, and native language (English versus others). Results: Patients born in Southeastern Asia (aOR: 0.54; 95% CI: 0.52–0.55), Eastern Asia (aOR: 0.63; 95% CI: 0.60–0.66), and India (aOR: 0.64; 95% CI: 0.63–0.66) had a lower likelihood of having a telehealth consultation compared to those born in Australia or New Zealand. Northern America, British Isles, and most European countries did not present with a statistically significant difference. Additionally, higher education levels (aOR: 1.34; 95% CI: 1.26–1.42) was associated with an increase in the likelihood of a telehealth consultation, while being from a non-English-speaking country was associated with a reduced likelihood (aOR: 0.83; 95% CI: 0.81–0.84). Conclusions: This study provides evidence showing differences in telehealth use associated with birth country. Strategies to ensure continued healthcare access for patients, whose native language is not English, such as providing interpreter services for telehealth consultations, would be beneficial. Perspectives: Understanding cultural and linguistic differences may reduce health disparities in telehealth access in Australia and could present an opportunity to promote healthcare access in diverse communities

N=1 superstring in 2+2 dimensions

In this paper we construct a (2,2) dimensional string theory with manifest N=1 spacetime supersymmetry. We use Berkovits' approach of augmenting the spacetime supercoordinates by the conjugate momenta for the fermionic variables. The worldsheet symmetry algebra is a twisted and truncated ``small'' N=4 superconformal algebra. The realisation of the symmetry algebra is reducible with an infinite order of reducibility. We study the physical states of the theory by two different methods. In one of them, we identify a subset of irreducible constraints, which is by itself critical. We construct the BRST operator for the irreducible constraints, and study the cohomology and interactions. This method breaks the SO(2,2) spacetime symmetry of the original reducible theory. In another approach, we study the theory in a fully covariant manner, which involves the introduction of infinitely many ghosts for ghosts

BRST Operator for Superconformal Algebras with Quadratic Nonlinearity

We construct the quantum BRST operators for a large class of superconformal and quasi--superconformal algebras with quadratic nonlinearity. The only free parameter in these algebras is the level of the (super) Kac-Moody sector. The nilpotency of the quantum BRST operator imposes a condition on the level. We find this condition for (quasi) superconformal algebras with a Kac-Moody sector based on a simple Lie algebra and for the $Z_2\times Z_2$--graded superconformal algebras with a Kac-Mody sector based on the superalgebra $osp(N\vert 2M)$ or $s\ell(N+2\vert N)$.Comment: 13 pages, plain tex, CTP TAMU-27/93, IC/93/16

Light States in Chern-Simons Theory Coupled to Fundamental Matter

Motivated by developments in vectorlike holography, we study SU(N) Chern-Simons theory coupled to matter fields in the fundamental representation on various spatial manifolds. On the spatial torus T^2, we find light states at small `t Hooft coupling \lambda=N/k, where k is the Chern-Simons level, taken to be large. In the free scalar theory the gaps are of order \sqrt {\lambda}/N and in the critical scalar theory and the free fermion theory they are of order \lambda/N. The entropy of these states grows like N Log(k). We briefly consider spatial surfaces of higher genus. Based on results from pure Chern-Simons theory, it appears that there are light states with entropy that grows even faster, like N^2 Log(k). This is consistent with the log of the partition function on the three sphere S^3, which also behaves like N^2 Log(k). These light states require bulk dynamics beyond standard Vasiliev higher spin gravity to explain them.Comment: 58 pages, LaTeX, no figures, Minor error corrected, references added, The main results of the paper have not change

de Sitter Supersymmetry Revisited

We present the basic $\mathcal{N} =1$ superconformal field theories in four-dimensional de Sitter space-time, namely the non-abelian super Yang-Mills theory and the chiral multiplet theory with gauge interactions or cubic superpotential. These theories have eight supercharges and are invariant under the full $SO(4,2)$ group of conformal symmetries, which includes the de Sitter isometry group $SO(4,1)$ as a subgroup. The theories are ghost-free and the anti-commutator $\sum_\alpha\{Q_\alpha, Q^{\alpha\dagger}\}$ is positive. SUSY Ward identities uniquely select the Bunch-Davies vacuum state. This vacuum state is invariant under superconformal transformations, despite the fact that de Sitter space has non-zero Hawking temperature. The $\mathcal{N}=1$ theories are classically invariant under the $SU(2,2|1)$ superconformal group, but this symmetry is broken by radiative corrections. However, no such difficulty is expected in the $\mathcal{N}=4$ theory, which is presented in appendix B.Comment: 21 pages, 2 figure