13 research outputs found
Generalized N = 2 Super Landau Models
We generalize previous results for the superplane Landau model to exhibit an
explicit worldline N = 2 supersymmetry for an arbitrary magnetic field on any
two-dimensional manifold. Starting from an off-shell N = 2 superfield
formalism, we discuss the quantization procedure in the general case
characterized by two independent potentials on the manifold and show that the
relevant Hamiltonians are factorizable. In the restricted case when both the
Gauss curvature and the magnetic field are constant over the manifold and, as a
consequence, the underlying potentials are related, the Hamiltonians admit
infinite series of factorization chains implying the integrability of the
associated systems. We explicitly determine the spectrum and eigenvectors for
the particular model with CP^1 as the bosonic manifold.Comment: 26 page
Hierarchy of N=8 Mechanics Models
Using the N=4 superspace approach in one dimension (time), we construct
general N=8 supersymmetric mechanics actions for the multiplets (b,8,8-b)
classified in hep-th/0406015, with the main focus on the previously unexplored
cases of (8,8,0), (7,8,1) and (6,8,2), as well as on (5,8,3) for completeness.
N=8 supersymmetry of the action amounts to a harmonicity condition for the
Lagrangian with respect to its superfield arguments. We derive the generic
off-shell component action for the ``root'' multiplet (8,8,0), prove that the
actions for all other multiplets follow from it through automorphic dualities
and argue that this hierarchical structure is universal. The bosonic target
geometry in all cases is conformally flat, with a unique scalar potential
(except for the root multiplet). We show that the N=4 superfield constraints
respect the full R-symmetry and find the explicit realization of its quotient
over the manifest R-symmetry on superfields and component fields. Several
R-symmetric N=4 superfield Lagrangians with N=8 supersymmetry are either newly
found or reproduced by a simple universal method.Comment: 33 pages, Latex, minor corrections, version to appear in Nucl. Phys.
Galilean Conformal Mechanics from Nonlinear Realizations
We apply the nonlinear realizations method for constructing new Galilean
conformal mechanics models. Our starting point is the Galilean conformal
algebra which is a non-relativistic contraction of its relativistic
counterpart. We calculate Maurer-Cartan one-forms, examine various choices of
the relevant coset spaces and consider the geometric inverse Higgs-type
constraints which reduce the number of the independent coset parameters and, in
some cases, provide dynamical equations. New Galilean conformally invariant
actions are derived in arbitrary space-time dimension D=d+1 (no central
charges), as well as in the special dimension D=2+1 with one "exotic" central
charge. We obtain new classical mechanics models which extend the standard
(D=0+1) conformal mechanics in the presence of d non-vanishing space
dimensions.Comment: v2: 1 + 20 pages, small changes in Sect.5 and two references added;
the version will appear in Phys.Rev.
Massive Nonlinear Sigma Models and BPS Domain Walls in Harmonic Superspace
Four-dimensional massive N=2 nonlinear sigma models and BPS wall solutions
are studied in the off-shell harmonic superspace approach in which N=2
supersymmetry is manifest. The general nonlinear sigma model can be described
by an analytic harmonic potential which is the hyper-Kahler analog of the
Kahler potential in N=1 theory. We examine the massive nonlinear sigma model
with multi-center four-dimensional target hyper-Kahler metrics and derive the
corresponding BPS equation. We study in some detail two particular cases with
the Taub-NUT and double Taub-NUT metrics. The latter embodies, as its two
separate limits, both Taub-NUT and Eguchi-Hanson metrics. We find that domain
wall solutions exist only in the double Taub-NUT case including its
Eguchi-Hanson limit.Comment: 35 pages, 4 figures, minor corrections and references added, to
appear in NP
Non-English languages enrich scientific knowledge : The example of economic costs of biological invasions
We contend that the exclusive focus on the English language in scientific researchmight hinder effective communication between scientists and practitioners or policymakerswhose mother tongue is non-English. This barrier in scientific knowledge and data transfer likely leads to significant knowledge gaps and may create biases when providing global patterns in many fields of science. To demonstrate this, we compiled data on the global economic costs of invasive alien species reported in 15 non-English languages. We compared it with equivalent data from English documents (i.e., the InvaCost database, the most up-to-date repository of invasion costs globally). The comparison of both databases (similar to 7500 entries in total) revealed that non-English sources: (i) capture a greater amount of data than English sources alone (2500 vs. 2396 cost entries respectively); (ii) add 249 invasive species and 15 countries to those reported by English literature, and (iii) increase the global cost estimate of invasions by 16.6% (i.e., US$ 214 billion added to 1.288 trillion estimated fromthe English database). Additionally, 2712 cost entries - not directly comparable to the English database - were directly obtained frompractitioners, revealing the value of communication between scientists and practitioners. Moreover, we demonstrated how gaps caused by overlooking non-English data resulted in significant biases in the distribution of costs across space, taxonomic groups, types of cost, and impacted sectors. Specifically, costs from Europe, at the local scale, and particularly pertaining to management, were largely under-represented in the English database. Thus, combining scientific data from English and non-English sources proves fundamental and enhances data completeness. Considering non-English sources helps alleviate biases in understanding invasion costs at a global scale. Finally, it also holds strong potential for improving management performance, coordination among experts (scientists and practitioners), and collaborative actions across countries. Note: non-English versions of the abstract and figures are provided in Appendix S5 in 12 languages. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/ by/4.0/).Peer reviewe
Superconformal field theory in three dimensions: correlation functions of conserved currents
Gypsy moth (Lymantria dispar (Linnaeus))
Educação Superior::Ciências Biológicas::ZoologiaApresenta imagem de uma larva da Mariposa cigana, que é mais conhecida por se alimentar de mais de 300 árvores e arbustos, em cima de uma folh
Gypsy moth (Lymantria dispar (Linnaeus))
Educação Superior::Ciências Biológicas::ZoologiaApresenta imagem de uma larva da mariposa cigana, que é mais conhecida por se alimentar de mais de 300 árvores e arbusto
Gypsy moth (Lymantria dispar (Linnaeus))
Educação Superior::Ciências Biológicas::ZoologiaApresenta imagem de uma larva da Mariposa cigana, que é mais conhecida por se alimentar de mais de 300 árvores e arbustos, em cima de uma folh
Gypsy moth (Lymantria dispar (Linnaeus))
Educação Superior::Ciências Biológicas::ZoologiaApresenta imagem de uma larva da mariposa cigana, que é mais conhecida por se alimentar de mais de 300 árvores e arbusto