Hall viscosity, spin density, and torsion

We investigate the relationship between Hall viscosity, spin density and response to geometric torsion. For the most general effective action for relativistic gapped systems, the presence of non-universal terms implies that there is no relationship between torsion response and Hall viscosity. We also consider free relativistic and non-relativistic microscopic actions and again verify the existence of analogous non-universal couplings. Explicit examples demonstrate that torsion response is unrelated to both Hall viscosity and spin density. We also argue that relativistic gapped theories must have vanishing Hall viscosity in Lorentz invariant vacuums.Comment: 15 pages, 1 figur

The Euler current and relativistic parity odd transport

For a spacetime of odd dimensions endowed with a unit vector field, we introduce a new topological current that is identically conserved and whose charge is equal to the Euler character of the even dimensional spacelike foliations. The existence of this current allows us to introduce new Chern-Simons-type terms in the effective field theories describing relativistic quantum Hall states and (2+1) dimensional superfluids. Using effective field theory, we calculate various correlation functions and identify transport coefficients. In the quantum Hall case, this current provides the natural relativistic generalization of the Wen-Zee term, required to characterize the shift and Hall viscosity in quantum Hall systems. For the superfluid case this term is required to have nonzero Hall viscosity and to describe superfluids with non s-wave pairing.Comment: 24 pages. v2: added citations, corrected minor typos in appendi

Effective Field Theory of Relativistic Quantum Hall Systems

Motivated by the observation of the fractional quantum Hall effect in graphene, we consider the effective field theory of relativistic quantum Hall states. We find that, beside the Chern-Simons term, the effective action also contains a term of topological nature, which couples the electromagnetic field with a topologically conserved current of $2+1$ dimensional relativistic fluid. In contrast to the Chern-Simons term, the new term involves the spacetime metric in a nontrivial way. We extract the predictions of the effective theory for linear electromagnetic and gravitational responses. For fractional quantum Hall states at the zeroth Landau level, additional holomorphic constraints allow one to express the results in terms of two dimensionless constants of topological nature.Comment: 4 page

Value-Driven Analysis of New Paradigms in Space Architectures: An Ilities-Based Approach

Current commercial, civil, and military space architecture designs perform exquisitely and reliably. However, today’s architecture paradigms are also characterized by expensive launches, large and expensive high-performance spacecraft, long development cycles, and wide variations in ground architectures. While current assets provide high-quality services, and future assets are slated to improve performance within the same design frameworks, proposed future architectures may not be capitalizing on technology improvements, system innovations, or policy alternatives explored during the last two decades. This paper identifies five “trends” along which space architectures may develop, aimed at granting systems several “ilities,” such as resiliency, robustness, flexibility, scalability, and affordability. The trends examined include: commercialization of space, significant reductions in launch costs and the development of hybrid or reusable launch systems, development of on-orbit infrastructure and servicing, aggregation or disaggregation of orbital assets, and the automation and standardization of ground architectures. Further refinement of these key technological and system trends could result in major paradigm shifts in the development and fielding of space operations as well as lead to space architecture designs in the future that are radically different from those today. Within the framework of systems engineering ilities and risk management, this paper reviews current literature surrounding these new change trends and justifies their potential to cause significant paradigm shifts. By examining the work and research conducted so far through an ilities-based approach, systems engineers can more fully appreciate the value being offered by these trends

Effect of different physio-chemical factors on sex expression and fruit yield in green-house cucumber

Male flower expression is considered an important aim in greenhouse cucumber breeding for creating paternal lines as a base for hybrid progeny. The study was carried out to evaluate the effects of different treatments on sex expression and fruit yield of cucumber in two different season (autumn-winter and spring-summer), in particular this research focuses on the influence of 1) usage of two chemical agents: silver thiosulphate [Ag(S2O3)2-3] and silver nitrate (AgNO3) at different concentration, respectively 200 and 500 ppm and 100, 200 and 300 ppm 2) plant development stages at the moment of the treatment (5, 10, and 15-leaf growth stages) and 3) application of single or double sprayings. Analysis of variance showed that season, chemical applications and number of spaying had significant effect on the induction of a higher number of male flowers. A positive significant effect of season suggested that longer days and higher temperature promote the formation of male flowers in cucumber. This study showed that male flower production was induced by all concentrations of silver ions, especially high concentrations. Important traits related to change of sex expression such as the number of days to male flowering and the number of male flowers are more affected by different interactions of studied factors in contrast to vegetative and yield related traits. Also, the quadruple interaction effects indicated that silver ion could change sex expression at  higher temperatures and longer days (second season in summer) with high concentration when applied in 15 leaf stage for AgNO3 and 5 and 15 leaf growth stage for Ag(S2O3)2-3 with double spraying. Consequently, female lines can be induced to male flowering with silver ions, thus increasing the feasibility of large scale seed production of gynoecious × gynoecious cucumber hybrid