Spin Phase Research Articles

Comparison of serum versus EDTA plasma in canine major crossmatch reactions

Protocols for crossmatch reactions vary in veterinary medicine, particularly regarding the use of recipient serum vs plasma. Sources suggest that major crossmatch results might differ when recipient plasma is used instead of serum, but there are conflicting reports as to the exact effects on the results. The aim of this study was to determine the frequency and degree of discrepancy, if any, between canine major crossmatch reactions using serum versus EDTA plasma, performed via a standard tube method. One hundred duplicate canine major crossmatch reactions were performed with both serum and EDTA plasma from 100 different "recipient" dogs against erythrocytes from a single, healthy "donor." Decreasing concentrations of a rabbit anti-dog erythrocyte antibody were added to generate strong positive, weak positive, and negative results for each crossmatch reaction. Crossmatch results were followed through the following phases: immediate spin, cold, warm, albumin, and Coombs. Semi-quantitative results were compared between reactions using serum vs EDTA plasma. Weak positive, major crossmatch reactions were significantly more likely to demonstrate stronger agglutination in EDTA plasma compared with serum in the immediate spin phase, cold phase, warm phase, and albumin phase (P<0.001). There was no statistically significant difference between serum and EDTA plasma results in the Coombs' phase (P=0.313). In this experimental setting, EDTA plasma and serum were both deemed acceptable for use in canine major crossmatch reactions. EDTA plasma might be preferable to detect weak agglutination with more sensitivity and reduce recipient blood volumes needed to complete the crossmatch reaction.

Quantum-entanglement entropy and double occupancy in a 1-D Holstein-Hubbard model at half-filling

The nature of the cross-over region of the spin-density wave and the charge-density wave phases of the one-dimensional Holstein-Hubbard model is examined at half filling. The vibrational modes have been removed by applying a set of canonical transformations followed by an averaging with a many-phonon state. The resulting effective Hubbard Hamiltonian is dealt exactly by using the method of Bethe-Ansatz to get the ground state energy of the system. The quantum entanglement entropy and double occupancy are calculated at the boundary of the spin and charge density wave phases to confirm the existence of an intervening metallic phase. • 1-D Holstein-Hubbard model is studied using a series of unitary transformations. • Phonon coherence and correlations are incorporated in an accurate way. • A generalized many-phonon state is used to obtain an effective Hubbard model. • Entanglement entropy and double occupancy are calculated. • A broader metallic phase is obtained at the boundary of the CDW-SDW phase.

Corrections to the singlet-length distribution and the entanglement entropy in random singlet phases

We consider random singlet phases of spin-$\frac{1}{2}$, random, antiferromagnetic spin chains, in which the universal leading-order divergence $\frac{\ln 2}{3}\ln\ell$ of the average entanglement entropy of a block of $\ell$ spins, as well as the closely related leading term $\frac{2}{3}l^{-2}$ in the distribution of singlet lengths are well known by the strong-disorder renormalization group (SDRG) method. Here, we address the question of how large the subleading terms of the above quantities are. By an analytical calculation performed along a special SDRG trajectory of the random XX chain, we identify a series of integer powers of $1/l$ in the singlet-length distribution with the subleading term $\frac{4}{3}l^{-3}$. Our numerical SDRG analysis shows that, for the XX fixed point, the subleading term is generally $O(l^{-3})$ with a non-universal coefficient and also reveals terms with half-integer powers: $l^{-7/2}$ and $l^{-5/2}$ for the XX and XXX fixed points, respectively. We also present how the singlet lengths originating in the SDRG approach can be interpreted and calculated in the XX chain from the one-particle states of the equivalent free-fermion model. These results imply that the subleading term next to the logarithmic one in the entanglement entropy is $O(\ell^{-1})$ for the XX fixed point and $O(\ell^{-1/2})$ for the XXX fixed point with non-universal coefficients. For the XX model, where a comparison with exact diagonalization is possible, the order of the subleading term is confirmed but we find that the SDRG fails to provide the correct non-universal coefficient.

Quantum phase transition of many interacting spins coupled to a bosonic bath: Static and dynamical properties

By using worldline and diagrammatic quantum Monte Carlo techniques, matrix product state, and a variational approach \`a la Feynman, we investigate the equilibrium properties and relaxation features of a quantum system of $N$ spins antiferromagnetically interacting with each other, with strength $J$, and coupled to a common bath of bosonic oscillators, with strength $\ensuremath{\alpha}$. We show that, in the Ohmic regime, a Beretzinski-Thouless-Kosterlitz quantum phase transition occurs. While for $J=0$ the critical value of $\ensuremath{\alpha}$ decreases asymptotically with $1/N$ by increasing $N$, for nonvanishing $J$ it turns out to be practically independent on $N$, allowing to identify a finite range of values of $\ensuremath{\alpha}$ where spin phase coherence is preserved also for large $N$. Then, by using matrix product state simulations, and the Mori formalism and the variational approach \`a la Feynman jointly, we unveil the features of the relaxation, that, in particular, exhibits a nonmonotonic dependence on the temperature reminiscent of the Kondo effect. For the observed quantum phase transition we also establish a criterion analogous to that of the metal-insulator transition in solids.

Silver doped titania nanotubes incorporated photocatalytic dual layer antibiofouling hollow fiber membrane for palm oil wastewater treatment

Photocatalytic dual layer hollow fiber membrane (DLHFM) is advantageous over its single layer counterpart due to a better photocatalyst dispersion on the outer layer to maximize the potential of the photocatalyst in improving the overall membrane performance. In this study, a polyvinylidene fluoride (PVDF) dual-layer hollow fiber membrane with antibiofouling properties was successfully synthesized via dry-wet spinning phase inversion method, where the Ag-TNT was incorporated onto the outer layer membrane for photocatalytic degradation of AT-POME pigments in a submerged membrane photoreactor (SMPR). The results revealed that the incorporation of Ag-TNT into the PVDF matrix increased pure water flux from 16.20 L/m2 h for pristine PVDF membrane to 37.12 L/m2 h. The synergistic advantages of photocatalysis and membrane filtration was exhibited by the photocatalytic Ag-TNT membrane which showed the highest AT-POME color removal efficiency of 84.0% compared to the other membranes prepared in this work. With the presence of silver nanoparticles, the modified membrane exhibited antibacterial efficiency of 95.8% with a 1.73 mm inhibition zone around the membrane against P. aeruginosa. Based on the results obtained, the photocatalytic PVDF Ag-TNT membrane showed immense potential as an innovative technology for water reclamation in the palm oil industry.

Berry phases of higher spins due to internal geometry of Majorana constellation and relation to quantum entanglement

Majorana stars, the antipodal directions associated with the coherent states that are orthogonal to a spin state, provide a visualization and a geometric understanding of the structures of general quantum states. For example, the Berry phase of a spin-1/2 is given by half the solid angle enclosed by the close path of its Majorana star. It is conceivable that the Berry phase of higher spins may also be related to the geometry of the Majorana constellation. We find that for a spin-1 state, besides the expected contributions from the solid angles enclosed by the close paths of the two Majorana stars, the Berry phase includes a term related to the twist of the relative position vector around the barycenter vector of the two Majorana stars, i.e., the self-rotation of the constellation. Interestingly, if the spin-1 state is taken as a symmetrized two-qubit state, the extra contribution to the Berry phase is given by the self-rotation of the Majorana constellation weighted by the quantum entanglement of the two qubits. This discovery alludes to the relevance of the Majorana stellar geometry in representing the deep structures of quantum states and of quantum entanglement.

Double-focusing geometry for phase correction in neutron resonance spin-echo spectroscopy

Neutron spin phase correction is an essential technique for achieving a high energy resolution in neutron spin-echo experiments. We propose a double-focusing geometry in which two identical ellipsoidal mirrors are arranged in series. This arrangement enables us to correct the path length differences for large divergent beams using a complete ellipsoidal focusing mirror. In this study, we evaluated the effectiveness of this geometry both analytically and numerically. A Fourier time of 1 μs is achievable using this geometry.

Quantum phases and thermodynamics of a frustrated spin-1/2 ladder with alternate Ising–Heisenberg rung interactions

We study a frustrated two-leg spin ladder with alternate isotropic Heisenberg and Ising rung exchange interactions, whereas, interactions along legs and diagonals are Ising-type. All the interactions in the ladder are anti-ferromagnetic in nature and induce frustration in the system. This model shows four interesting quantum phases: (i) stripe rung ferromagnetic (SRFM), (ii) stripe rung ferromagnetic with edge singlet (SRFM-E), (iii) anisotropic antiferromagnetic (AAFM), and (iv) stripe leg ferromagnetic (SLFM) phase. We construct a quantum phase diagram for this model and show that in stripe rung ferromagnet (SRFM), the same type of sublattice spins (either isotropic S-type or discrete anisotropic σ-type spins) are aligned in the same direction. Whereas, in anisotropic antiferromagnetic phase, both S and σ-type of spins are anti-ferromagnetically aligned with each other, two nearest S spins along the rung form an anisotropic singlet bond whereas two nearest σ spins form an Ising bond. In large Heisenberg rung exchange interaction limit, spins on each leg are ferromagnetically aligned, but spins on different legs are anti-ferromagnetically aligned. The thermodynamic quantities like specific heat C v (T), magnetic susceptibility χ(T) and thermal entropy S(T) are also calculated using the transfer matrix method for various phases. The magnetic gap in the SRFM and the SLFM can be noticed from χ(T) and C v (T) curves.

Beam dynamics corrections to the Run-1 measurement of the muon anomalous magnetic moment at Fermilab

This paper presents the beam dynamics systematic corrections and their uncertainties for the Run-1 data set of the Fermilab Muon g-2 Experiment. Two corrections to the measured muon precession frequency $\omega_a^m$ are associated with well-known effects owing to the use of electrostatic quadrupole (ESQ) vertical focusing in the storage ring. An average vertically oriented motional magnetic field is felt by relativistic muons passing transversely through the radial electric field components created by the ESQ system. The correction depends on the stored momentum distribution and the tunes of the ring, which has relatively weak vertical focusing. Vertical betatron motions imply that the muons do not orbit the ring in a plane exactly orthogonal to the vertical magnetic field direction. A correction is necessary to account for an average pitch angle associated with their trajectories. A third small correction is necessary because muons that escape the ring during the storage time are slightly biased in initial spin phase compared to the parent distribution. Finally, because two high-voltage resistors in the ESQ network had longer than designed RC time constants, the vertical and horizontal centroids and envelopes of the stored muon beam drifted slightly, but coherently, during each storage ring fill. This led to the discovery of an important phase-acceptance relationship that requires a correction. The sum of the corrections to $\omega_a^m$ is 0.50 $\pm$ 0.09 ppm; the uncertainty is small compared to the 0.43 ppm statistical precision of $\omega_a^m$.

Review on Fiber-Optic Vortices and Their Sensing Applications

Vortex beams have attracted much attention in recent years due to unique features of the phase or polarization singularity in the center part of beams. Various applications have been explored by the vortex beams including optical communication, optical tweezer, etc. Especially, the vortex beams for optical sensing applications have emerged. Compared with the traditional Gaussian beams, the vortex beams enable the optical sensing with the degree of freedom by controlling the spin and orbital phase and polarization. In this review article, we have discussed the theory of polarization and phase vortices, and then summarized the vortex beam generation in optical fiber and their sensing applications. It is hoped that the article can intrigue further research interest and development in fiber vortices for sensing applications.

Origin of the orbital polarization of Co2+ in La2CoTiO6 and ( LaCoO3)1+(LaTiO3)1 : A DFT+U and DFMT study

The unequal electronic occupation of localized orbitals (orbital polarization), and associated lowering of symmetry and degeneracy, play an important role in the properties of transition metal oxides. Here, we examine systematically the underlying origin of orbital polarization, taking as exemplar the 3$d$ manifold of Co$^{2+}$ in a variety of spin, orbital and structural phases in the double perovskite La$_2$CoTiO$_6$ and the (001) superlattice (LaCoO$_3$)$_1$+(LaTiO$_3$)$_1$ systems. Superlattices are of specific interest due to the large experimentally observed orbital polarization of their Co cations. Based on first principles calculations, we find that robust and observable orbital polarization requires symmetry reduction through the lattice structure; the role of local electronic interactions is to greatly enhance the orbital polarization.

On the radio frequency dependence of the pulse delay phenomenon in PSR B0943+10

ABSTRACT We report the result of measurements of a gradual shift of the integrated pulses towards later spin phase of the anomalous pulsar B0943+10 at high radio frequencies. We have used observations from the Arecibo Observatory and the GMRT at 327 and 325 MHz correspondingly. For the measurements, we have proposed a special method for calculating the correct positions of the partially merged two components of the pulse profile shape with significant temporal changes in their amplitude ratio. The exponential change in the pulse phase with an amplitude of 4 ms and characteristic time of about 1 h has been found. Comparison of our measurements at 325 and 327 MHz with those at the lower frequencies of 25–80, 62 and 112 MHz have shown that the character of the process does not depend on frequency across a wide frequency range. The result is very important for constraining the nature of the delay. It supports the assumption that the process results from changes in the vacuum gap near the surface of the pulsar. The further correlation between changes in the pulse phase and its intensity is discussed.

Nonreciprocity of spin waves in the conical helix state

Nonreciprocity emerges in nature and in artificial objects from various physical origins, being widely utilized in contemporary technologies as exemplified by diode elements in electronics. While most of the nonreciprocal phenomena are realized by employing interfaces where the inversion symmetry is trivially lifted, nonreciprocal transport of photons, electrons, magnons, and possibly phonons also emerge in bulk crystals with broken space inversion and time reversal symmetries. Among them, directional propagation of bulk magnons (i.e., quanta of spin wave excitation) is attracting much attention nowadays for its potentially large nonreciprocity suitable for spintronic and spin-caloritronic applications. Here, we demonstrate nonreciprocal propagation of spin waves for the conical spin helix state in Cu2OSeO3 due to a combination of dipole and Dzyaloshinskii-Moriya interactions. The observed nonreciprocal spin dispersion smoothly connects to the hitherto known magnetochiral nonreciprocity in the field-induced collinear spin state; thus, all the spin phases show diode characteristics in this chiral insulator.

Vortex structure in magnetic nanodots: Dipolar interaction, mobile spin model, phase transition and melting

We study in this article properties of a nanodot embedded in a support by Monte Carlo simulation. The nanodot is a piece of simple cubic lattice where each site is occupied by a mobile Heisenberg spin which can move from one lattice site to another under the effect of the temperature and its interaction with neighbors. We take into account a short-range exchange interaction between spins and a long-range dipolar interaction. We show that the ground-state configuration is a vortex around the dot central axis: the spins on the dot boundary lie in the xy plane but go out of plane with a net perpendicular magnetization at the dot center. Possible applications are discussed. Finite-temperature properties are studied. We show the characteristics of the surface melting and determine the energy, the diffusion coefficient and the layer magnetizations as functions of temperature.

An eDrive-Based Estimation Method of the Laundry Unbalance and Laundry Inertia for Washing Machine Applications

The estimation of the laundry unbalance and laundry inertia is fundamental in washing machine applications. On the one hand, the estimation and management of the laundry unbalance play a pivotal role in reducing mechanical stress and noise during the spinning phase. On the other hand, the laundry inertia’s estimation, performed at the beginning of the washing cycle, allows for the determination of the proper amounts of water and detergent, the water temperature, and the tumbling time. In this way, good washing performance is obtained, avoiding the waste of energy and resources. Moreover, at the end of the washing cycle, the laundry inertia’s accurate estimation is needed to properly manage the spinning phase. With the aim of optimizing the washing performance, this paper proposes a novel method to estimate the laundry unbalance and laundry inertia. The proposed approach does not require additional sensors, since it uses the already implemented motor control scheme, enhanced by a dedicated position-tracking observer. Experimental results have been carried out on a commercial horizontal-axis direct-drive washer, demonstrating the validity of the proposed solution.

Pulsed field gradient NMR diffusion measurement in nanoporous materials

Labeling in diffusion measurements by pulsed field gradient (PFG) NMR is based on the observation of the phase of nuclear spins acquired in a constant magnetic field with purposefully superimposed field gradients. This labeling does in no way affect microdynamics and provides information about the probability distribution of molecular displacements as a function of time. An introduction of the measuring principle is followed by a detailed description of the ranges of measurements and their limitation. Particular emphasis is given to an explanation of possible pitfalls in the measurements and the ways to circumvent them. Showcases presented for illustrating the wealth of information provided by PFG NMR include a survey on the various patterns of concentration dependence of intra-particle diffusion and examples of transport inhibition by additional transport resistances within the nanoporous particles and on their external surface. The latter information is attained by combination with the outcome of tracer exchange experiments, which are shown to become possible via a special formalism of PFG NMR data analysis. Further evidence provided by PFG NMR concerns diffusion enhancement in pore hierarchies, diffusion anisotropy and the impact of diffusion on chemical conversion in porous catalysts. A compilation of the specifics of PFG NMR and of the parallels with other measurement techniques concludes the paper.

Spin and Charge Correlations Effect on Quantum Entanglement for Extended Hubbard Model

The presence of long-range spin and charge correlations underlies a variety of physical phenomena in condensed-matter systems, especially, in qubits systems. This work aims to study quantum entanglement versus spin and charge correlations in qubits systems modeled by 1D Extended Hubbard Model. The considered model is parameterized by on-site coulomb interaction energy U, off-site coulomb interaction energy V and exchange spin-spin interaction γJ, where γ is the anisotropy parameter. In charge space, the quantum entanglement reaches its maximum value for an optimal interatomic distance that checks the condition U = 2V. Moreover, in spin phase the quantum entanglement increases with external magnetic field h, especially, for anisotropic Ising model with γ = 1.

Influence of the inversion factor on Madelung constants in spinel systems

The influence of the inversion factor on the Madelung constants of the partially inversed spinel systems Mg-Zn-(FeTM)O4 where (TM = Ni and Cr) have been investigated. These results showed that both the ordering parameter, Q and the inversion factor, λ depend on the oxygen positional parameter, u in these spinels. An inverse relation between lattice constants and the inversion factor is well defined in these spinels. From the cation distributions the sample with λ = 2/3, Q = 1 and maximum configurational entropy Sc(≈15.876 J/mol,K) should represents the sample with the complete randomness of the cation distributions in these spinels and can be written as ((MgZn)1/3Fe2/3)[(MgZn)2/3Fe1/3TM3/3]O4. The total Madelung constants Mtot increase as the inversion factor decreases in these spinels. The presence of the Zn2+ (Mg2+) cations enhances the normal (inverse) spin phase arrangements; this might be caused by the strong tendency of the Zn2+ (Mg2+) cations to reside at the tetrahedral (octahedral) sites. The Zn- (Mg-) spinels are largely having the normal (inverse) type structure. Values of the ordering, inversion and randomness parameters moves towards the spinel structure normality as the Zn content (x) increases in the sample. Values of the calculated total Madelung constants, Mtot increase as uavg increases. An inverse relation between the lattice constants and the inversion factor, λ is well defined in these spinels.

Design Optimization of Composite Curved Rod for Wind Tunnel Virtual Flight Test Based on Multi-island Genetic Algorithm

The curved rod of carbon fibrecomposite is the key component of the large angle three degree of freedom virtual flight test device. This article takes the composite curved rod as the research object, Establish a finite element analysis model and analyze its strength and stiffness under the initial design conditions, the RSM response surface approximation model and multi-island genetic algorithm are used to optimize the carbon fibre composite angle of each layer of the composite curved rod, so that the maximum deformation displacement of the curved rod is minimized, As far as possible, the influence of the center of mass of the Virtual flight test model on the wind tunnel test data should be reduced. The optimization results show that relative to the initial design, the failure factor of the composite curved rod is reduced by 65.4%, the rigidity is increased by 35.94%, and the maximum deformation is reduced by 44.5%. In order to realize the simulation of flight motions close to 90 ° angle of attack in a horizontal wind tunnel, it provides equipment guarantee for the research of stall deviation, initial phase of spin and stable spin.

Quantum Lifshitz points and fluctuation-induced first-order phase transitions in imbalanced Fermi mixtures

We perform a detailed analysis of the phase transition between the uniform superfluid and normal phases in spin- and mass-imbalanced Fermi mixtures. At mean-field level we demonstrate that at temperature $T\to 0$ the gradient term in the effective action can be tuned to zero for experimentally relevant sets of parameters, thus providing an avenue to realize a quantum Lifshitz point. We subsequently analyze damping processes affecting the order-parameter field across the phase transition. We show that, in the low energy limit, Landau damping occurs only in the symmetry-broken phase and affects exclusively the longitudinal component of the order-parameter field. It is however unavoidably present in the immediate vicinity of the phase transition at temperature $T=0$. We subsequently perform a renormalization-group analysis of the system in a situation, where, at mean-field level, the quantum phase transition is second order (and not multicritical). We find that, at $T$ sufficiently low, including the Landau damping term in a form derived from the microscopic action destabilizes the renormalization group flow towards the Wilson-Fisher fixed point. This signals a possible tendency to drive the transition weakly first-order by the coupling between the order-parameter fluctuations and fermionic excitations effectively captured by the Landau damping contribution to the order-parameter action.