Volume 62, Number 34, 2017
Theoretical, Mathematical, and Computational Physics
A Solution to the Naturalness Problem Amir H. Fariborz, Renata Jora Romanian Journal of Physics 62,
106 (2017)
We present a solution to the naturalness problem of the electroweak scale based on a change of variable in the Fourier space of non supersymmetric nature that transforms a boson into a fermion and viceversa. This is exemplified for that part of the standard model Lagrangian that contains a Dirac fermion coupled with the Higgs field. The full Lagrangian which contains both the initial particles and the partners obtained through this method is invariant under the symmetry associated to this change of variables and is free of quadratic divergences to the scalar particles present in the Lagrangian. The partners appear mostly as “offshell” states thus explaining their experimental absence at any particle accelerators.
Gaussian Quantum Steering of Two Bosonic Modes in a Thermal Environment Tatiana Mihaescu, Aurelian Isar Romanian Journal of Physics 62,
107 (2017)
EinsteinPodolskyRosen steerability of quantum states is a property that is different from entanglement and Bell nonlocality. We describe the time evolution of a measure that quantifies steerability for arbitrary bipartite Gaussian states in a system consisting of two bosonic modes embedded in a common thermal environment. We work in the framework of the theory of open quantum systems. If the initial state of the subsystem is taken of Gaussian form, then the evolution under completely positive quantum dynamical semigroups assures the preservation in time of the Gaussian form of the state. We study the Gaussian quantum steering in terms of the covariance matrix under the influence of the thermal environment and find out that the thermal noise and dissipation destroy the steerability between the two parts. We make a comparison with other quantum correlations for the same system, and show that, unlike Gaussian quantum discord, which is decreasing asymptotically in time, the Gaussian quantum steerability suffers a ”sudden death” behaviour  it vanishes in a finite time, like quantum entanglement.
Rational Solution of the Nonlocal Nonlinear Schroedinger Equation and Its Application in Optics Yongshuai Zhang, Deqin Qiu, Yi Cheng, Jingsong He Romanian Journal of Physics 62,
108 (2017)
We derive a kind of rational solution with two free phase parameters of the nonlocal nonlinear Schrödinger equation, which satisfies the paritytime (PT) symmetry condition. In addition, the analyticity of the rational solution about the phase parameters and the classification of this solution according to its asymptotic amplitude are studied in detail. Furthermore, the gain/loss profile related to an optical system is remarkably similar to the profile of the imaginary part of a PTsymmetric potential generated by the abovementioned rational solution.
Weakly Integrable CamassaHolmType Equations Peilong Dong, Zhiwei Wu, Jingsong He Romanian Journal of Physics 62,
109 (2017)
Series of deformed CamassaHolmtype equations are constructed using the Lagrangian deformation and Loop algebra splittings. They are weakly integrable in the sense of modified Lax pairs.
Exact Solutions of a Generalized Bratu Equation Lazhar Bougoffa Romanian Journal of Physics 62,
110 (2017)
In this short article, we derive the closedform solutions of a generalized Bratu equation, which arises in many fields of science and engineering such as radiative heat transfer, combustion theory, and nanotechnology.
Numerical Solutions of TwoDimensional Mixed VolterraFredholm Integral Equations via Bernoulli Collocation Method R. M. Hafez, E. H. Doha, A. H. Bhrawy, D. Baleanu Romanian Journal of Physics 62,
111 (2017)
The mixed VolterraFredholm integral equations (VFIEs) arise in various physical and biological models. The main purpose of this article is to propose and analyze efficient Bernoulli collocation techniques for numerically solving classes of twodimensional linear and nonlinear mixed VFIEs. The novel aspect of the technique is that it reduces the problem under consideration to a system of algebraic equations by using the GaussBernoulli nodes. One of the main advantages of the present approach is its superior accuracy. Consequently, good results can be obtained even by using a relatively small number of collocation nodes. In addition, several numerical results are given to illustrate the features of the proposed technique.
Atomic, Molecular, and Optical Physics
Comparison between Propagation Characteristics of Some Photonic FiberBased Plasmonic Sensors V. A. Popescu Romanian Journal of Physics 62,
204 (2017)
The birefringence characteristics of recently studied photonic fiberbased plasmonic sensors are investigated using a finite element method. The fiber is made by a SiO$_2$ core with fourteen small air holes (of radius $r$) placed at the vertices of a tworing hexagonal lattice in which two horizontal holes surrounded a smaller central hole (of radius $r_1$) are omitted to introduce the birefringence behavior. The radius of two airholes in the second ring at the same row with the central airhole is reduced to $r/2$. This fiber structure supports two types (I and II) of resonant modes. In this sensor there is a stronger interaction between the core and plasmon modes of type II near the phase matching point for the xcomponent of the electric field as compared to the ycomponent, in contradiction with recently published results for a similar fiber structure. The advantages of the xpolarization of the core modes of type II are a smaller spectral width and a smaller value of the propagation length due to a large absorption at the resonance wavelength.
Optical Amplification and Reshaping Based on Rogue Wave in the Femtosecond Regime Yan Wang, Lu Li Romanian Journal of Physics 62,
205 (2017)
Based on the higher order nonlinear Schrödinger equation, the amplification and the reshaping of ultrashort pulses are investigated. The numerical results show that the direct amplification of femtosecond pulses can be achieved by injecting a continuous wave (CW) and filtering the CW at suitable positions in the presence of higherorder dispersion and nonlinear effects. The combination of continuous wave pump and spectral filter placed suitably in fiber plays the role of the amplifier, which can be used to longhaul transmission of pulses. As an example, longhaul transmission with four amplification periods is demonstrated. The effects of higherorder dispersion and Raman effect on the longhaul transmission of pulses are also discussed.
Study of the Optical Absorption Coefficient Variation in SodaLime and Borosilicate Glasses Due to Their Exposure to GammaRays MR. Ioan Romanian Journal of Physics 62,
206 (2017)
In this paper, the relative variation of the optical absorption for two types of glasses (sodalime and borosilicate), due to their exposure to gammarays is studied. The optical absorptions were determined by measuring the transmission optical powers of a 633 nm continuous wave HeNe laser beam passing through the gammarays exposed glass samples. The optical powers were measured by using of a UVVIS type powermeter. The relative optical absorption variations for the two types of glass, when were exposed to gammarays, were different. For the sodalime type glass, the optical absorption variation was of about 2.4 % and for the borosilicate one was of about 16 %. The relative variations of the transmitted optical powers through the glass samples as a function of the absorbed gammarays doses of 68.7 % in the first case, respectively 80.6 % in the second one, contributed to the results. Moreover, the analytical relation between the optical absorption coefficient variation and the magnitude of the absorbed doses which produced it, was determined. This method may be also used to determine the magnitude and the rate of change for the “glass browning” phenomenon induced by the gammarays to exposed optical transmission materials, such as the lens and the optical transmission windows operating in gammaray environments, but also the glass materials used as dosimeters for estimating the gammaray absorbed doses.
Condensed and Soft Matter Physics
Nonlinear Transitions in Single, Double and Triple δDoped GaAs Structures E. Ozturk Romanian Journal of Physics 62,
603 (2017)
In this study, the intersubband optical absorption coefficient and the refractive index change in single, double, and triple deltadoped GaAs structure will investigate for the uniform doping distribution model. The electronic properties of the structure such as potential profile, subband energies and wave functions will be calculated by solving the Schrödinger and the Poisson equations selfconsistently. Dependence on different doping wells of the intersubbands nonlinear transitions is more important for potential variations in photodetectors and optical modulators. These structures will play a key role in researches of quantum electronics and photonic devices in the future.
Vacuum Annealing Effect on the Structural and Optical Properties of Antimony Trioxide Thin Films N. Tigau, S. ConduracheBota, R. Drasovean, J. Cringanu, R. Gavrila Romanian Journal of Physics 62,
604 (2017)
Antimony trioxide (Sb_{2}O_{3}) thin films were deposited onto glass substrates held at 25°C using the thermal vacuum evaporation technique. The films were annealed at 250°C in vacuum after evaporation. The morphostructural properties of the films were studied by Xray diffraction (XRD) and atomic force microscopy (AFM), respectively. The optical properties were investigated for both the asdeposited and annealed film in the wavelength range of 190–1100 nm. The optical constants such as the refractive index, the absorption coefficient and the energy bandgap were determined from the transmission spectra, by using Swanepoel’s method.
Biophysics and Medical Physics
Biomedical Application of Biogenic Ferrihydrite Nanoparticles C.G. Chilom, D.M. Găzdaru, M. Bălăşoiu, M. Bacalum, S.V. Stolyar, A.I. Popescu Romanian Journal of Physics 62,
701 (2017)
Spectroscopic properties of biogenic ferrihydrite nanoparticles, produced by Klebsiella oxytoca, were investigated. Their interaction with two serum albumins was moderate. A very weak stabilization of protein structure to denaturation, in the presence of nanoparticles, was put in evidence. Nanoparticle cytotoxicity and their hemolytic effect were studied on healthy and tumour cells.
Environmental and Earth Physics
Magnetite/Tartaric Acid Nanosystems for Experimental Study of Bioeffects on Zea Mays Growth M. Răcuciu, D. Creangă Romanian Journal of Physics 62,
804 (2017)
Experimental study was carried out with magnetic nanosystems supplied to Zea mays cereal species. Diluted suspensions of colloidal magnetite nanoparticles (MNPs) stabilized in water were supplied in the culture medium: volume fraction ranging between 50 and 300 μl/l, equivalent with nanoparticle concentrations between 3.7 μg/ml and 22.5 μg/ml. The impact of MNPs administration was recorded at the level of: seedling growth and green tissue contents of assimilatory pigments. Photosynthesis efficacy appeared to be stimulated by MNPs as resulted from slight but statistically significant increase of the chlorophyll a/chlorophyll b ratio.
Comparison Study of Inorganic Cements to the Conditioning of the Secondary Radioactive Waste M. Nicu, L. Ionascu, F. Dragolici, E. Neacsu, L. Zicman, B. Obreja Romanian Journal of Physics 62,
805 (2017)
Portland cement is currently the most widely used as a matrix for shielding and immobilization of low level radioactive waste. Performance in the long term of cement based matrix depends on the cement formulation as well as the interactions between cement and radioactive waste components. Also a comparison of Portland cement with other composite cements was made. This paper presents the results regarding the influence of cement and the concentrate content on properties of waste form cement, such as: fluidity, setting time, and compressive strength (in fresh and hardened state). A simulated concentrate and different types of cement were used in this study. The engineering properties of the resulting paste or mortar are correlated with XRD characterization data in order to obtain an optimized formula of cement based matrix.
Investigation and Modeling of Fixed Bed Cesium Sorption on Nickel Ferrocyanide, Precipitated on Silica Gel L.R. Zicman, E. Neacsu, L. Done, L.C. Tugulan, C. Alexandru, F.N. Dragolici, M. Nicu, L.F. Ionacsu, B.T. Obreja, G. Dogaru, T. Dobre Romanian Journal of Physics 62,
806 (2017)
Cesium sorption on nickel ferrocyanide, precipitated on silica gel (PNFSG) from low and intermediate level liquid radioactive waste was investigated in a fixedbed column. The breakthrough characteristics of the ionexchange system were studied at different Cs concentrations (50–150 mg/L), bed heights (20–60 mm) and feed flow rates (1–6 mL/min). Mathematical models of Thomas and Yoon–Nelson were applied to the experimental data to investigate the column performance. The results fitted well the Thomas and Yoon–Nelson models with correlation coefficient values of R^{2} ≥ 0.91.
