XY Type Research Articles

Anisotropic magnetic and quadrupolar H−T phase diagram of CeRh2As2

The tetragonal heavy-fermion compound CeRh2As2 has intriguing low-temperature symmetry-breaking phases whose nature is unclear. The unconventional superconducting phase is complemented by other normal-state phases which presumably involve ordering of 4f electron multipoles supported by the Kramers doublets split by the tetragonal crystal electric field (CEF). The most striking aspect is the pronounced anisotropic H−T phase boundary for in-plane and out-of plane field directions. Using a localized 4f CEF model we demonstrate that its essential features can be understood as the result of competing low-field easy-plane magnetic order and field-induced quadrupolar order of xy type. We present calculations based on coupled multipole random phase approximation response function approach as well as molecular field treatment in the ordered regime. We use an analytical approach for a reduced quasiquartet model and numerical calculations for the complete CEF level scheme. We discuss the quantum critical properties as function of multipolar control parameters and explain the origin of a pronounced ac anisotropy of the H−T phase diagram. Finally, the field and temperature evolution of multipolar order parameters is derived and the high-field phase diagram is predicted. Published by the American Physical Society 2024

Thermal quantum correlations in a three-qubit spin chain under an in-homogeneous magnetic field

The thermal quantum correlations of a three-qubit spin chain of XY type under an in-homogeneous magnetic field have been investigated, where by considering magnetic fields with different magnitudes [Formula: see text], [Formula: see text] and [Formula: see text] for each spin, the quantum correlations between the adjacent and the non-adjacent qubits (spins) have been studied. For this purpose, the concurrence as an entanglement quantifier and the trace distance discord as a discord-like quantifier have been computed for the corresponding bipartite subsystems with the reduced density matrices [Formula: see text], [Formula: see text] and [Formula: see text]. The differences between the concurrence and the trace distance discord, are explained in detail. Their dependence on the parameters of the uniform magnetic field [Formula: see text], the temperature [Formula: see text], and the in-homogeneity parameter [Formula: see text] is discussed so that the thermal correlation decreases by increasing the mentioned parameters. Also, the results show that by changing and controlling the parameters [Formula: see text], [Formula: see text] and [Formula: see text], especially the in-homogeneous magnetic field [Formula: see text], it is possible that the correlation value between non-adjacent spins, i.e. [Formula: see text] can be reached to a greater value than the thermal correlations between adjacent spins, i.e. [Formula: see text] and [Formula: see text]. Moreover, it is shown that the trace distance [Formula: see text] between the non-adjacent spins has always a lower value than those of the adjacent spins [Formula: see text] and [Formula: see text]. Finally, the results show that in-homogeneous magnetic field b can be effective for improving thermal quantum correlation.

The nature of halogen bond in model OC∙∙∙XY systems from the energy decomposition analysis perspective

This work represents the theoretical study results of the halogen bond's nature, based upon six model complexes of OC∙∙∙XY type, in which X and Y are halogen atoms. Local Molecular Orbital Energy Decomposition Analysis (LMOEDA), Quantum Theory Atom in Molecules (QTAIM), including geometrical parameters, the values and energy of intermolecular interaction and Molecular Electrostatic Potential (MESP) have been referred to in this investigation. A critical assessment of the LMOEDA studies is also presented. This shows a strong dependency of the results on calculation methods. Some DFT methods have as expected given very consistent results; however, Grimme’s dispersion corrections and some long-range separated functions in DFT do not work with the used decomposition energy procedure. Electron density and Laplacian values confirm linear dependencies in connection to halogen bond energy than in the case of ΔEint = f(RC∙∙∙X). MESP calculations also confirm the usefulness of σ-hole theory.

The genomic architecture of the sex-determining region and sex-related metabolic variation in Ginkgobiloba.

Sex differences and evolutionary differences are critical biological issues. Ginkgo is an ancient lineage of dioecious gymnosperms with special value for studying the mechanism of sex determination in plants. However, the major genetic basic underlying sex chromosomes remains to be uncovered. In this study, we identify the sex-determining region of Ginkgo and locate it to the area from megabases 48 to 75 on chromosome 2. We find that the male sex-determining region of Ginkgo contains more than 200 genes, including four MADS-box genes, demonstrating that the Ginkgo sex determination system is of the XY type. We also find that genetic sex differences result in specialized flavonoid metabolism and regulation in each sex. These findings establish a foundation for revealing the molecular mechanism of sexual dimorphism and promoting the development of the Ginkgo industry.

Mathematical Modeling and Sensitivity Analysis of the Existence of Male Calico Cats Population Based on Cross Breeding of All Coat Colour Types

The coat color of cats is normally governed by genes found on the X chromosome in both male chromosome XY and female chromosome XX. The meiosis failure in the process of gametogenesis leads to the birth of three-colored male cats caused by an excess of the X chromosome in the male chromosome type XY. The chromosome structure of three-color male cats, called male calico cats, appeared similar to the XXY Klinefelter’s syndrome in human. Mathematical modeling and investigation of the factors that influence the infrequency of male calico cats are our main objectives of this paper. In addition, we also discuss the possible contributions and strategies to overcome the scarcity of these cats. We construct a mathematical model based on a combination of genes in the chromosome that regulates the color of cat coat on the fertilization process. The mathematical model is given as a six-dimensional system of differential equations. Sensitivity analysis is used to investigate the important parameters in the existence of male calico cats. Our finding states that the probability of normal male cats meiosis is a crucial parameter in the maintenance of the existence of male calico cats. Furthermore, one of the strategies that we could recommend in maintaining the existence of male calico cats is minimizing the value of the successful meiosis probability of normal male cats.

A Design Method of Precise Positioning Stage in Vacuum Environment by Disturbance Observer with Position Dependent Parameter

The semiconductor inspection apparatus using an electron beam in the vacuum environment requires high resolution and measuring accuracy because the semiconductor devices which are smaller and thinner are required by growing market of the smartphone and the tablet PC. Herewith, high positioning accuracy of XY stage working in vacuum environment is also required. However, it is hard to introduce the aerostatic bearing like semiconductor photolithography apparatus into vacuum environment due to technical difficulties and cost. Therefore, friction drive type XY stage was adopted. Nevertheless, it is difficult to precisely control and adjust characteristics and behavior as for friction drive XY stage which is working in vacuum environment. The characteristic of XY stage fluctuates in vacuum environment even though it has been precisely adjusted in the atmosphere. Moreover, nobody can re-adjust mechanical characteristics unless they open a vacuum chamber. It means an electron beam is halted, and the long time is necessary to restart emitting an electron beam. Therefore, this paper proposes a design approach which is useful for high precision positioning of XY stage in vacuum environment by the feedback of estimated disturbance which includes position dependent parameter. Position dependent parameter is determined by measuring evaluation function value at each position. Furthermore, proposed design method is also useful to maintain performance for aged deterioration. In this paper, issue of XY stage is mentioned at first. Then, a design approach which comprises a disturbance observer including position dependent parameter and state feedback is described. At last, experiment results are shown.

A VSEPR-inspired force field for determining molecular properties of PF5

ABSTRACTValence Shell Electron Pair Repulsion (VSEPR) theory, commonly taught in introductory chemistry courses, provides a basis for understanding the molecular structures of molecules of the type XY, where X is a central atom surrounded by m Y ligands. While VSEPR is generally thought of only as a qualitative theory, Bartell and coworkers constructed a semi-quantitative model potential to address the physical underpinnings of VSEPR by introducing a points-on-a-sphere (POS) potential such that all X-Y bonds are of fixed length and all atoms Y repel each other. More than forty years ago, this simple model was shown to be effective in reproducing relative quadratic and cubic bending force constants for a variety of binary XY compounds when compared to values computed with semi-empirical and fairly primitive methods. The work presented here endeavours to go beyond the model used in the early investigations by Bartell and coworkers. Specifically, stretching force constants are clearly omitted from any POS model with a fixed radius, and are (primitively) included here by treating all X-Y bonds as simple (and equivalent) Morse oscillators. With the additional degrees of freedom in the parametrization that come from the Morse potential, the resulting model was investigated. The degree to which this simple mechanical model can reproduce quadratic and cubic force fields for PF is studied here, as well as how it works for a more difficult problem – the energetics and transition state properties for the intermediate in the (Berry) pseudorotation process that interchanges axial and equatorial fluorines in this prototype molecule. The five parameter Morse-POS model is shown to be do quite well in describing the quadratic and cubic force fields, as well as the pseudorotation process, a fairly impressive feat given the naivete of the model.

On the number of topological orbits of complex germs in classes (xy, xa + yb)

We show that there exist an infinite number of topological orbits in classes of complex map germs from the plane to the plane that have a representative of type (xy, xa + yb), with (a, b) ≠ = (2, 3) or (2, 5). Our key tool to prove this existence is the existence (or not) of stems in the class; these germs are not -finitely determined and allow the determination of a non-finite number of topological orbits. We also show that the class (xy, x2 + y5) has two topological orbits.

Primary sex determination of placental mammals: a modelling study uncovers dynamical developmental constraints in the formation of Sertoli and granulosa cells.

BackgroundPrimary sex determination in placental mammals is a very well studied developmental process. Here, we aim to investigate the currently established scenario and to assess its adequacy to fully recover the observed phenotypes, in the wild type and perturbed situations. Computational modelling allows clarifying network dynamics, elucidating crucial temporal constrains as well as interplay between core regulatory modules.ResultsRelying on a comprehensive revision of the literature, we define a logical model that integrates the current knowledge of the regulatory network controlling this developmental process. Our analysis indicates the necessity for some genes to operate at distinct functional thresholds and for specific developmental conditions to ensure the reproducibility of the sexual pathways followed by bi-potential gonads developing into either testes or ovaries. Our model thus allows studying the dynamics of wild type and mutant XX and XY gonads. Furthermore, the model analysis reveals that the gonad sexual fate results from the operation of two sub-networks associated respectively with an initiation and a maintenance phases. At the core of the process is the resolution of two connected feedback loops: the mutual inhibition of Sox9 and ß-catenin at the initiation phase, which in turn affects the mutual inhibition between Dmrt1 and Foxl2, at the maintenance phase. Three developmental signals related to the temporal activity of those sub-networks are required: a signal that determines Sry activation, marking the beginning of the initiation phase, and two further signals that define the transition from the initiation to the maintenance phases, by inhibiting the Wnt4 signalling pathway on the one hand, and by activating Foxl2 on the other hand.ConclusionsOur model reproduces a wide range of experimental data reported for the development of wild type and mutant gonads. It also provides a formal support to crucial aspects of the gonad sexual development and predicts gonadal phenotypes for mutations not tested yet.Electronic supplementary materialThe online version of this article (doi:10.1186/s12918-016-0282-3) contains supplementary material, which is available to authorized users.

Calculation of the Vibrational-Rotational Energy Structure of Molecules with Tetrahedral Symmetry of the Type XY 4

On the basis of the formalism of irreducible tensor operators in symmetrized form, a Hamiltonian has been constructed, an algorithm has been developed, and a software package has been created that allows the calculation of high-resolution spectra for various polyads of interacting vibrational states and also makes it possible to interpret the spectra and solve the inverse spectroscopic problem for molecules with tetrahedral symmetry.

Polarized neutron diffraction and anisotropic exchange in pyrochlores

Rare earth frustrated pyrochlore magnets are among the materials that exhibit no long range order down to the lowest explored temperatures. To better understand the many complex phenomena observed in the pyrochlores, knowledge of the local interactions present in these materials is necessary. In the pyrochlore lattice, selection between Ising, Heisenberg, or XY types of the anisotropy cannot be based on the analysis of the macroscopic properties because of the presence of four equivalent local anisotropy (<111> -type) axes. Then only an average over the four axes can be measured by classical methods. Polarized neutron diffraction based on the `site susceptibility approach' (A Gukasov and P. J. Brown, J. Phys.: Cond. Matt., 14, 8831, 2002) allows to determine the local susceptibility tensor on the magnetic site. Its temperature dependence in the paramagnetic phase can be accounted for by the crystal field anisotropy and a molecular field tensor that encompasses exchange and dipolar interactions. It was found that for rare earth pyrochlores an isotropic exchange model is not suitable to explain their magnetic behavior and that, instead, the exchange interaction appear anisotropic to large extent (H. Cao et al., PRL 103, 056402, 2009). The experimental evaluation of the anisotropic exchange in pyrochlores can provide a clue to the richness of the phase diagram observed in rare earth frustrated magnets.

Design of an Optimal PID Controller by Genetic Algorithms for a Pantograph Type XY Platform

This study focused on the development of an intelligent motion control system for a nanoscale micro-platform based on the pantograph mechanism. The platform is designed to satisfy the need for achieving high accuracy and process efficiency in the manufacture of increasingly small industrial products. The target platform is mounted on a pantograph and small x-y sliders, and is driven by a traditional X-Y platform with common precision. The goal of this study is to drive the target platform to move in the region of 20mm × 20mm for the positioning, and repeatedly positioning accuracy error is less than 800 nm by a traditional X-Y platform. Due to the different PID parameters will affect platform positioning accuracy and system response for the two axes, the optimal PID parameters by the Genetic algorithms was proposed. The simulation and experimental results indicated that the proposed method is feasible for development of an intelligent motion control system for the nanoscale micro-platform positioning.

Embryological basis of the virgin birth of Jesus

Virgin Mary gave birth to Jesus without a father. A scenario is presented here for this miraculous event. She is a chimera of 46,XX/46,XY type resulting from the fusion of two embryos of different sex types and both ovary and testis develop in Her body. It is well known that in chimera XX cells tend to gather on the left side while XY cells on the right; therefore, an ovary develops at the left side with an oviduct and a testis develops at the right side of the abdominal cavity with no duct. Both gonads are functional and produce oocyte and spermatozoa respectively after puberty. At the time of ovulation, estrogens leads to a negative pressure in the left oviduct and this vacuum effect helps oocyte and sperms to be picked-up into the tube, taking both types of gametes to the fertilization site in the left oviduct. Because of the higher temperature of the oocyte at the left ovary, fertilization occurs with a Y-bearing sperm to give rise to a XY male embryo which becomes miraculously Jesus.

Cytogenetic and molecular genetic analysis of gynogenesis in Megalobrama amblycephala using spermatozoa of Erythroculter ilishaeformis

In the present study we used both cytogenetics (measurement of DNA content, detection of chromosome number, observation of gonadal development)and molecular genetics(microsatellite analysis)to analyze the biological characteristics of gynogenetic M. amblycephala, which werecreatedthrough gynogenesis induced via UV-irradiated E. ilishaeformis spermatozoa to fertilize M. amblycephala eggs. The maternal genome was duplicated by cold shock in 0~4℃ cold water to form a population of M. amblycephala with 48 chromosomes whose DNA content was identical to the diploid maternal parent. Morphologically, this group of gynogenetic M. amblycephala was similar to the control group. All gynogenetic M. amblycephala were female, and no males were found in any of the examined gynogenetic M. amblycephala, providing cytogenetic evidence that our gynogenetic M. amblycephala are type XY. At the same time, microsatellite analysis showed that 63 alleles were amplified in the three test groups of gynogenetic M. amblycephala. Overall, the population of gynogenetic M. amblycephala observed heterozygosity average, and the expected average was significantly lower than the parental averages, demonstrating that after generation gynogenesis the gene homozygosity of M. amblycephala was significantly higher than the ordinary bream and E. ilishaeformis, making it a pure line. The genetic proximity of gynogenetic M. amblycephala to M. amblycephala demonstrates that gynogenesis passes on maternal DNA. Gynogenetic groups developed in this study may provide good genetic material for future breeding projects of M. amblycephala.

Cytogenetic Analysis of Otiorhynchus bisulcatus (Fabricius, 1781) and O.(Zadrehus) atroapterus (De Geer, 1775) (Coleoptera, Curculionidae, Entiminae) using C Bands, NORs, and DAPI/CMA3 Staining

The structure of the karyotypes of two Otiorhynchus species belonging to separate subgenera, viz. Otiorhynchus s.str. bisulcatus and O. (Zadrehus) atroapterus, is compared and described for the first time. Both species have the same chromosome number (2n = 22), sex chromosome system of an achiasmate parachute type (Xy(p)), symmetric karyotype with the prevalence of metacentrics, similar meiotic behaviour, localization of NORs and positive DAPI signals. The main differences involve the morphology of autosomes and the X chromosome in the C-banding pattern and DAPI/CMA3 signals as well as in the presence of additional B chromosomes.

Spin fluctuations with two-dimensional XY behavior in a frustratedS=12square-lattice ferromagnet

The spin dynamics of the layered square-lattice vanadate Pb2VO(PO4)2 is investigated by electron spin resonance at various magnetic fields and at temperatures above magnetic ordering. The linewidth divergence towards low temperatures seems to agree with isotropic Heisenberg-type spin exchange suggesting that the spin relaxation in this quasi-two dimensional compound is governed by low-dimensional quantum fluctuations. However, a weak easy- plane anisotropy of the g factor points to the presence of a planar XY type of exchange. Indeed, we found that the linewidth divergence is described best by XY-like spin fluctuations which requires a single parameter only. Therefore, ESR-probed spin dynamics could establish Pb2VO(PO4)2 as the first frustrated square lattice system with XY-inherent spin topological fluctuations.

Magnetocaloric effect in M–pyrazole–[Nb(CN)8] (M = Ni, Mn) molecular compounds

We report a study of magnetocaloric effect (MCE) in cyanido-bridged {[MII(pyrazole)4]2[NbIV(CN)8]⋅4H2O}n molecular compounds where M = Ni, Mn, pyrazole = C3H4N2. The substances show a sharp phase transition to a long range magnetically ordered state, with ferromagnetic coupling between M and Nb sublattices in the case of the Ni-based sample 1 (Tc = 13.4 K) and ferrimagnetic coupling for the Mn-based sample 2 (Tc = 23.8 K). The magnetic entropy change ΔS due to applied field change ΔH as a function of temperature was determined by the magnetization and heat capacity measurements. The maximum value of ΔS at μ0ΔH = 5 T is 6.1 J mol−1 K−1 (5.9 J kg−1 K−1) for 1 at T = 14 K and 6.7 J mol−1 K−1 (6.5 J kg−1 K−1) for 2 at T = 25 K. MCE data at different applied fields have been presented as one universal curve, which confirms magnetic transitions in 1 and 2 to be of second order. The temperature dependences of the n exponent characterizing the dependence of ΔS on ΔH have been obtained. The n(Tc) values, consistent with the shape of the magnetization curves, pointed to the 3D Heisenberg behaviour for 2 and some anisotropy, probably of the XY type, for 1. The (H/Tc)2/3 dependence of the maximum entropy change has been tested in the ferrimagnetic Mn2–L–[Nb(CN)8] (L = C3H4N2, C4H4N2) series.

Greenberger-Horne-Zeilinger generation protocol forNsuperconducting transmon qubits capacitively coupled to a quantum bus

We propose a circuit quantum electrodynamics (QED) realization of a protocol to generate a Greenberger-Horne-Zeilinger (GHZ) state for $N$ superconducting transmon qubits homogeneously coupled to a superconducting transmission line resonator in the dispersive limit. We derive an effective Hamiltonian with pairwise qubit exchange interactions of the XY type, $\tilde{g}(XX+YY)$, that can be globally controlled. Starting from a separable initial state, these interactions allow to generate a multi-qubit GHZ state within a time $t_{\text{GHZ}}\sim \tilde{g}^{-1}$. We discuss how to probe the non-local nature and the genuine $N$-partite entanglement of the generated state. Finally, we investigate the stability of the proposed scheme to inhomogeneities in the physical parameters.

Evaluation of entanglement measures in spin systems with the random phase approximation

We discuss a general formalism based on the mean field plus random phase approximation (RPA) for the evaluation of entanglement measures in the ground state of spin systems. The method provides a tractable scheme for determining the entanglement entropy as well as the negativity of finite subsystems, which becomes analytic in the case of systems with translational invariance, in one or D dimensions. The approach improves as the spin increases, and also as the interaction range or connectivity increases. Illustrative results for different types of entanglement entropies (single site, block and comb) in the ground state of a small spin lattice with ferromagnetic type XY couplings in a transverse field are shown and compared with the exact numerical result. Effects arising from symmetry breaking at the mean field level are also discussed.

Signatures of hidden-order symmetry in torque oscillations, elastic constant anomalies, and field-induced moments in URu2Si2

We discuss the conclusions on the symmetry of hidden order (HO) in URu2Si2 that may be drawn from recent torque experiments in rotating magnetic field by Okazaki et al. [1]. They are very sensitive to changes in the magnetic susceptibility induced by HO. We show that the observed twofold angular torque oscillations give evidence that hidden order has degenerate E- type (yz,zx) symmetry where both components are realised. The oscillations have the wrong characteristics or are absent for the 1D nontrivial representations like quadrupolar B1 (x^2-y^2) and B2 (xy) type HO or hexadecapolar A2(xy(x^2-y^2)) type HO. Therefore they may be excluded as candidates for hidden order. We also predict the field-angular variation of possible field-induced Bragg peaks based on underlying E-type order parameter and discuss the expected elastic constant anomalies.