Magnetic phase transitions in the LiNi0.9 M 0.1PO4 (M = Mn, Co) single crystals

The LiNiPO4, LiNi0.9Mn0.1PO4, and LiNi0.9Co0.1PO4 single crystals are studied with heat capacity and neutron diffraction measurements over the temperature interval (10–30) K. Two peaks are observed on the temperature dependence of heat capacity for LiNiPO4, and LiNi0.9Co0.1PO4 samples. One peak indicates the first order phase transition from an antiferromagnetic commensurate (C) structure to an incommensurate (IC) one upon heating. According to neutron diffraction, in LiNiPO4 the IC ordering is described by the propagation vector k = 2π/b(0, 0.080, 0) at the Néel temperature T N = 20.8 K, and k = 2π/b(0, 0.098, 0) at T N = 20.2(1) K for LiNi0.9Co0.1PO4. A further increase in temperature leads to the second order phase transition to a paramagnetic state at critical temperature T IC = 21.7 K and 21.1 K for LiNiPO4 and LiNi0.9Co0.1PO4, respectively. The C and IC phases coexist over the temperature interval (20.6–20.8) K and (20.2–21.2) K in LiNiPO4 and LiNi0.9Co0.1PO4, respectively. In the LiNi0.9Mn0.1PO4 the magnetic phase transition occurs at T N = 22.7 K, but a magnetic scattering is observed up to 24.6 K.

Efficiency increasing of the bidirectional teleportation protocol via weak and reversal measurements

In this suggested version of the bidirectional teleportation protocol, it is assumed that the used quantum channel passes through an amplitude damping channel. Therefore, some of its quantum correlations (entanglement) are lost and, consequently, its efficiency to implement this protocol decreases. The weak and the reversal measurements are used to recover the losses of these correlations, where the negativity, as a measure of entanglement is improved. In this context, we discussed the effect of the noisy strength on the fidelities of the bidirectional teleported states between the users. It is shown that, by applying the weak and the reversal measurements (WRM) on the initial quantum channel between the users, the fidelities of the teleported states are improved. Moreover, we showed that, the upper bounds of the teleported states depend on the initial states of the triggers and the strengths of WRM. It is worth noting that the WRM improves the quantum correlations of the shared channel and, hence, the fidelity of the teleported state if the initial fidelity of the teleported state is larger than 0.5

Reply to Comment on 'Inverse problem from the discrete spectrum in the D = 2 dimensional space'

We want to thank our colleague F. Fernandez for his interest and his careful reading of our paper "The inverse problem from discrete spectrum in the D = 2 dimensional space". We are confused to have left a number of mistakes in the manuscript.

Photonic schemes of distribution and reconstruction of an entangled state from hybrid entanglement between polarization and time-bin via quantum dot

We propose photonic schemes for the distribution and reconstruction of a two-qubit entangled state using a hybrid entangled state under a noisy quantum channel. First, to generate a hybrid entangled state correlated with polarizations and time-bins, we employ a quantum dot (QD)-cavity system (nonlinear optical gate) and linear optical devices to implement controlled operation. These schemes can achieve the distribution and reconstruction of a two-qubit entangled state from hybrid entanglement by utilizing only linear optical devices without a QD-cavity system (i.e., a nonlinear optical device) for users who want to share an entangled state under a noisy quantum channel. For a feasible realization of the proposed schemes, we analyze the interaction between the photons and QD-cavity system and demonstrate the experimental conditions under which the reliable performance of the QD-cavity system is achieved.

Comment on Inverse problem from discrete spectrum in the D = 2 dimensional space (2014 Phys. Scr. 989 085201)

We analyse a method for the construction of the potential-energy function from the moments of the ground-state density. The sum rule on which some expressions are based appear to be wrong, as well as the moments and potential-energy functions derived for some illustrative examples.

An ab-initio study of electronic and optical properties of RhXO3 (X = Ga, Ag) perovskites

The ab-initio computations were performed to study the electronic and optoelectronic properties of RhXO3 (X = Ga, Ag) using WIEN2k code. The RhGaO3 has band gap of 2.29 eV, and the behavior of RhAgO3 metallic. The sub-TDOS of the studied materials revealed that rhodium and oxygen atoms have significant contributions in the valence band and conduction band formation of both materials. The silver cation is responsible for the reasonable peaks appearing at the Fermi level of RhAgO3, which demonstrated the conducting nature of RhAgO3. The dielectric functions, optical conductivity, energy loss function, absorption coefficient, refractive index, extinction coefficient, and reflectivity are computed for these materials to understand the optical behavior of the studied materials. The analysis of optical properties ensure the RhGaO3 is a promising material for optoelectronics while RhAgO3 has metallic nature.

Structure of spherically symmetric objects: a study based on structure scalars

The aim of this paper is to explore the consequences of extra curvature terms mediated from f(R, T, Q) (where Q ≡ R μ ν T μ ν ) theory on the formation of scalar functions and their importance in the study of populations who are crowded with regular relativistic objects. For this purpose, we model our system comprising of non-rotating spherical geometry formed due to gravitation of locally anisotropic and radiating sources. After considering a particular f(R, T, Q) model, we form a peculiar relation among Misner-Sharp mass, tidal forces, and matter variables. Through structure scalars, we have modeled shear, Weyl, and expansion evolutions equations. The investigation for the causes of the irregular distribution of energy density is also performed with and without constant curvature conditions. It is deduced that our computed one of the f(R, T, Q) structure scalars (Y T ) has a vital role to play in understanding celestial mechanisms in which gravitational interactions cause singularities to emerge.

Photoelectric and magnetic properties of chemically synthesized Cd-Ni Ferrite nanomagnetic particles

Cadmium nickel (Cd-Ni) ferrite samples have been successfully synthesized via chemical co-precipitation technique. The structural analysis revealed the formation of FCC framework and Fe-phase in a trivalent state. The crystallite size is decreased with increasing Cd2+ ion composition whereas the lattice constant is increased. SEM was used to obtain the surface morphology and average grain size of the microstructure. The FTIR shows the formation of metal oxide, hydroxyl and carboxylic groups. EDX revealed the formation of Ni2+, Cd2+, Fe3+, and O2- ions in proper stoichiometric composition. Large optical losses were revealed by Cd2+ poor-NiFe2O4 samples whereas Cd2+ rich-CdxNi1-xFe2O4 samples revealed low optical losses and showed enhanced photoconductivity and photoelectric effect. Result from optical analysis showed that Cd2+ rich-CdxNi1-xFe2O4 nanoparticles can be used as infrared (IR) detector, ultraviolet (UV) filter and in optoelectronics device applications. VSM measurement showed an increase in saturation magnetization and decrease in coercivity as Cd2+ ion content is increased. The remanance magnetization and magnetic anisotropy were also examined. Photoluminescence (PL) spectroscopy examined the nature of the light emission of the samples at the excitation wavelength 380 nm and emission of series of colours such as red, green, yellow, orange and violet light at different wavelengths were found.

A simple mass oscillator metasurface design with linear phase shift

In this paper, a simple mass oscillator metasurface is designed, which can regulate the phase shift of flexural wave covering 0-2π by adjusting the number of mass oscillators on the connecting bar. Based on the forced vibration theory, there is a simple approximately linear relationship between the number and phase shift of mass oscillators, which can more intuitively and accurately predict the phase of different number of mass oscillators, and then realize the metasurface design of mass oscillators with different requirements. Therefore, arbitrary regulation of flexural waves, such as abnormal refraction, beam focusing, and self-acceleration, can be realized by reasonably arranging the number of mass oscillators. The results show that the proposed metasurface can be greatly simplified both in the establishment of phase shift relation and in the fabrication of structure configuration, and will have broad application potential in the engineering field.

Investigation of boron distribution and material migration on the W7-X divertor by picosecond LIBS

One set of horizontal target elements of the Test Divertor Units (TDU), retrieved from the Wendelstein 7-X (W7-X) vessel after the end of second divertor Operation Phase (OP1.2B) in Hydrogen (H), were investigated by picosecond Laser-Induced Breakdown Spectroscopy (ps-LIBS). The Boron (B) distribution, H pattern and the material erosion/deposition pattern on these target elements were analyzed with high depth resolution and mapped in the poloidal direction of W7-X. From the spectroscopic analysis, B, H, Carbon (C) and Molybdenum (Mo) were clearly identified. A non-uniformly distributed B pattern on these divertor target elements was determined by the combination of B layer deposition during the three boronizations and W7-X plasma operation with multiple erosion and deposition steps of B. Like the TDU, the analyzed target elements are made of fine grain graphite, but have two marker layers which allow us to determine the material migration via the ps-LIBS technique. Two net erosion zones including one main erosion zone with a peak erosion depth of 6.5 μm and one weak erosion with a peak erosion of 1.3 μm were determined. Between two net erosion zones, a net deposition zone with width of 135 mm and a thickness up to 3.5 μm at the peak deposition location was determined by the ps-LIBS technique. The B distributions are correlated with the erosion/deposition pattern and the operational time in standard magnetic configuration of W7-X in the phases after the boronizations. The thickness of the containing B layer on these target elements also correlates with the erosion/deposition depth, in which the thickness of the containing B layer varies spatially in poloidal direction between 0.1 μm and 6 μm. Complementary, Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) was employed also to verify and investigate the deposition layer thicknesses at typical net erosion and net deposition zones as well as to identify the three boronizations in depth.