13,986 research outputs found
R-matrices of three-state Hamiltonians solvable by Coordinate Bethe Ansatz
We review some of the strategies that can be implemented to infer an
-matrix from the knowledge of its Hamiltonian. We apply them to the
classification achieved in arXiv:1306.6303, on three state -invariant
Hamiltonians solvable by CBA, focusing on models for which the -matrix is
not trivial.
For the 19-vertex solutions, we recover the -matrices of the well-known
Zamolodchikov--Fateev and Izergin--Korepin models. We point out that the
generalized Bariev Hamiltonian is related to both main and special branches
studied by Martins in arXiv:1303.4010, that we prove to generate the same
Hamiltonian. The 19-vertex SpR model still resists to the analysis, although we
are able to state some no-go theorems on its -matrix.
For 17-vertex Hamiltonians, we produce a new -matrix.Comment: 22 page
Electron trapping and acceleration by the plasma wakefield of a self-modulating proton beam
It is shown that co-linear injection of electrons or positrons into the
wakefield of the self-modulating particle beam is possible and ensures high
energy gain. The witness beam must co-propagate with the tail part of the
driver, since the plasma wave phase velocity there can exceed the light
velocity, which is necessary for efficient acceleration. If the witness beam is
many wakefield periods long, then the trapped charge is limited by beam loading
effects. The initial trapping is better for positrons, but at the acceleration
stage a considerable fraction of positrons is lost from the wave. For efficient
trapping of electrons, the plasma boundary must be sharp, with the density
transition region shorter than several centimeters. Positrons are not
susceptible to the initial plasma density gradient.Comment: 9 pages, 9 figures, 1 table, 44 reference
Investigation of the Integrity of aC:H Coatings on Stainless Steel Micro-Moulds during Thermal Cycling
Micro-injection moulding (µIM) is a key technology for scaling down larger geometry components and can include functional features at the micrometre scale and as far as the sub-micrometre length scale. Thermal cycling of amorphous hydrogenated carbon (aC:H) coated Stainless Steel (SS) has been investigated to simulate long-term micro-injection moulding (µIM) wearing and damage. Micro indentations and cracks were made into the mould and predictions of the crack behaviour were made using thermal expansion models. Validation of the results was performed with multiple heating and cooling cycles along with hardness measurements of the damage to the coating. The undamaged surfaces showed no major deformation but the cracks were shown to propagate and change in behaviour. The first two heat cycles of the testing had the most significant effect on the substrate with varying thermal expansions of materials being the main cause. The aC:H is shown to have excellent properties for mould tool applications but delamination could occur in areas susceptible to damaged and periodic surface inspection will be required preserve tool life
Sobrevivência e desenvolvimento larval de Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) em hospedeiros alternativos.
Dois bioensaios foram conduzidos para avaliar a adaptação da lagarta-do-cartucho (LCM), Spodoptera frugiperda (J E Smith), em alguns de seus hospedeiros mais comuns nos agroecossistemas brasileiros. Em testes de confi namento, utilizando lagartas recém-eclodidas e seções de folhas de milho (Zea mays), sorgo granífero (Sorghum bicolor), sorgo selvagem (Sorghum sp.), braquiária Brachiaria sp., soja (Glycine max) e fumo (Nicotiana tabacum), foram observados a sobrevivência e o desenvolvimento larval da LCM. A sobrevivência da LCM nos diferentes hospedeiros foi acima de 80%, exceto nas folhas de fumo, que foi nula. O acúmulo de biomassa nas lagartas desenvolvidas na soja e na dieta artifi cial foi maior do que nos demais hospedeiros. A maior biomassa foi das pupas de lagartas alimentadas na dieta artifi cial e a menor nas lagartas e pupas provenientes da braquiária. A menor média do período larval foi dos insetos desenvolvidos no milho e a maior nos alimentados na dieta artifi cial Foram observadas três classes de período larval no milho; quatro no sorgo, na braquiária e na soja e cinco na dieta artifi cial As porcentagens aproximadas dos indivíduos da LCM que completaram o período larval foram 85% até o 12o. dia em milho; 77% em sorgo granífero, 80% em sorgo selvagem, 83% em soja e 68% em braquiária, até o 14o dia; e 69% na dieta artifi cial até o 17o dia. Portanto, a adaptação da LCM foi melhor no milho, intermediária no sorgo e na soja e pior na braquiária
Optimal Control of One-Qubit Gates
We consider the problem of carrying an initial Bloch vector to a final Bloch
vector in a specified amount of time under the action of three control fields
(a vector control field). We show that this control problem is solvable and
therefore it is possible to optimize the control. We choose the physically
motivated criteria of minimum energy spent in the control, minimum magnitude of
the rate of change of the control and a combination of both. We find exact
analytical solutions.Comment: 5 page
Dynamics and control of the expansion of finite-size plasmas produced in ultraintense laser-matter interactions
The strong influence of the electron dynamics provides the possibility of
controlling the expansion of laser-produced plasmas by appropriately shaping
the laser pulse. A simple irradiation scheme is proposed to tailor the
explosion of large deuterium clusters, inducing the formation of shock
structures, capable of driving nuclear fusion reactions. Such a scenario has
been thoroughly investigated, resorting to two- and three-dimensional
particle-in-cell simulations. Furthermore, the intricate dynamics of ions and
electrons during the collisionless expansion of spherical nanoplasmas has been
analyzed in detail using a self-consistent ergodic-kinetic model. This study
clarifies the transition from hydrodynamic-like to Coulomb-explosion regimes
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