Application of Pseudo-Hermitian Quantum Mechanics to a Complex Scattering Potential with Point Interactions

We present a generalization of the perturbative construction of the metric operator for non-Hermitian Hamiltonians with more than one perturbation parameter. We use this method to study the non-Hermitian scattering Hamiltonian: H=p^2/2m+\zeta_-\delta(x+a)+\zeta_+\delta(x-a), where \zeta_\pm and a are respectively complex and real parameters and \delta(x) is the Dirac delta function. For regions in the space of coupling constants \zeta_\pm where H is quasi-Hermitian and there are no complex bound states or spectral singularities, we construct a (positive-definite) metric operator \eta and the corresponding equivalent Hermitian Hamiltonian h. \eta turns out to be a (perturbatively) bounded operator for the cases that the imaginary part of the coupling constants have opposite sign, \Im(\zeta_+) = -\Im(\zeta_-). This in particular contains the PT-symmetric case: \zeta_+ = \zeta_-^*. We also calculate the energy expectation values for certain Gaussian wave packets to study the nonlocal nature of \rh or equivalently the non-Hermitian nature of \rH. We show that these physical quantities are not directly sensitive to the presence of PT-symmetry.Comment: 22 pages, 4 figure

Coherent and squeezed states of quantum Heisenberg algebras

Starting from deformed quantum Heisenberg Lie algebras some realizations are given in terms of the usual creation and annihilation operators of the standard harmonic oscillator. Then the associated algebra eigenstates are computed and give rise to new classes of deformed coherent and squeezed states. They are parametrized by deformed algebra parameters and suitable redefinitions of them as paragrassmann numbers. Some properties of these deformed states also are analyzed.Comment: 32 pages, 3 figure

Durability and wear resistance of laser-textured hardened stainless steel surfaces with hydrophobic properties

Hydrophobic surfaces are of high interest to industry. While surface functionalization has attracted significant interest, from both industry and research, the durability of engineered surfaces remains a challenge, as wear and scratches deteriorate their functional response. In this work, a cost-effective combination of surface engineering processes on stainless steel was investigated. Low-temperature plasma surface alloying was applied to increase surface hardness from 172 to 305 HV. Then, near-infrared nanosecond laser patterning was deployed to fabricate channel-like patterns that enabled superhydrophobicity. Abrasion tests were carried out to examine the durability of such engineered surfaces during daily use. In particular, the evolution of surface topographies, chemical composition, and water contact angle with increasing abrasion cycles were studied. Hydrophobicity deteriorated progressively on both hardened and raw stainless steel samples, suggesting that the major contributing factor to hydrophobicity was the surface chemical composition. At the same time, samples with increased surface hardness exhibited a slower deterioration of their topographies when compared with nontreated surfaces. A conclusion is made about the durability of laser-textured hardened stainless steel surfaces produced by applying the proposed combined surface engineering approach

Solvability and PT-symmetry in a double-well model with point interactions

We show that and how point interactions offer one of the most suitable guides towards a quantitative analysis of properties of certain specific non-Hermitian (usually called PT-symmetric) quantum-mechanical systems. A double-well model is chosen, an easy solvability of which clarifies the mechanisms of the unavoided level crossing and of the spontaneous PT-symmetry breaking. The latter phenomenon takes place at a certain natural boundary of the domain of the "acceptable" parameters of the model. Within this domain the model mediates a nice and compact explicit illustration of the not entirely standard probabilistic interpretation of the physical bound states in the very recently developed (so called PT symmetric or, in an alternative terminology, pseudo-Hermitian) new, fairly exciting and very quickly developing branch of Quantum Mechanics.Comment: 24 p., written for the special journal issue "Singular Interactions in Quantum Mechanics: Solvable Models". Will be also presented to the int. conference "Pseudo-Hermitian Hamiltonians in Quantum Physics III" (Instanbul, Koc University, June 20 - 22, 2005) http://home.ku.edu.tr/~amostafazadeh/workshop/workshop.ht

Obesity and type 2 diabetes in Northern Canada’s remote First Nations communities: the dietary dilemma

First Nations populations in Northwestern Ontario have undergone profound dietary and lifestyle transformations in less than 50 years, which have contributed to the alarming rise in obesity and obesity-related diseases, in particular type 2 diabetes mellitus. Even though the genetic background of First Nations peoples differs from that of the Caucasians, genetics alone cannot explain such a high prevalence in obesity and type 2 diabetes. Modifications in lifestyle and diet are major contributors for the high prevalence of chronic diseases. What remains constant in the literature is the persistent view that locally harvested and prepared foods are of tremendous value to First Nations peoples providing important health and cultural benefits that are increasingly being undermined by westernbased food habits. However, the complexities of maintaining a traditional diet require a multifaceted approach, which acknowledges the relationship between benefits, risks and viability that cannot be achieved using purely conventional medical and biological approaches. This brief review explores the biological predispositions and potential environmental factors that contribute to the development of the high incidence of obesity and obesity-related diseases in First Nations communities in Northern Canada. It also highlights some of the complexities of establishing exact physiological causes and providing effective solutions

Galactic pane infrared polarization survey (GPIPS): Data Release 4

The Galactic Plane Infrared Polarization Survey (GPIPS) seeks to characterize the magnetic field in the dusty Galactic disk using near-infrared stellar polarimetry. All GPIPS observations were completed using the 1.83 m Perkins telescope and Mimir instrument. GPIPS observations surveyed 76 deg2 of the northern Galactic plane, from Galactic longitudes 18°–56° and latitudes −1° to +1°, in the H band (1.6 μm). Surveyed stars span 7th–16th mag, resulting in nearly 10 million stars with measured linear polarizations. Of these stars, ones with m_H < 12.5 mag and polarization percentage uncertainties under 2% were judged to be high quality and number over one million. GPIPS data reveal plane-of-sky magnetic field orientations for numerous interstellar clouds for AV values to ∼30 mag. The average sky separation of stars with m_H < 12.5 mag is about 30″, or about 60 per Planck polarization resolution element. Matching to Gaia DR2 showed the brightest GPIPS stars are red giants with distances in the 0.6–7.5 kpc range. Polarization orientations are mostly parallel to the Galactic disk, with some zones showing significant orientation departures. Changes in orientations are stronger as a function of Galactic longitude than of latitude. Considered at 10′ angular scales, directions that show the greatest polarization fractions and narrowest polarization position angle distributions are confined to about 10 large, coherent structures that are not correlated with star-forming clouds. The GPIPS polarimetric and photometric data products (Data Release 4 catalogs and images) are publicly available for over 13 million stars.Accepted manuscrip

Effect of dietary fiber, genetic strain and age on the digestive metabolism of broiler chickens

In this study, 360 male broilers, out of which 240 of a fast-growing strain (Cobb500), and 120 of a slow-growing strain (Label Rouge), were used to evaluate the effect of dietary fiber on digesta transit time and digestive metabolism during the period of 1 to 42 days of age. A completely randomized experimental design with a 3x2 factorial arrangement was applied, consisting of three groups of birds (slow-growing – SG; fast-growing fed ad libitum – FGAL; and fast-growing pair-fed with SG broilers – FGPF) and two iso-protein diets (a 3100 kcal ME/kg low-fiber diet –LFD- and a 2800 kcal ME/ kg high-fiber diet –HFD- with 14% wheat bran and 4% oat hulls). HFD-fed birds presented lower ME retention (p < 0.001) and lower dry matter metabolizability (DMM) (p < 0.001), which is possibly related to the shorter digesta transit time observed in these birds (p < 0.001). DMM was reduced with age, whereas metabolizable energy remained almost constant (p < 0.001) independently of strain. This may be related to the increase in feed intake as birds age. The slowgrowing strain did not present better utilization of the high-fiber diet as compared to the fast-growing strain in none of the analyzed ages, even though showing a significant better use of fiber and dietary energy from 31 days of age