Coupling Constants Research Articles

Phase transitions and composite order in U(1)N lattice London models

The phase diagrams and the nature of the phase transitions in multicomponent gauge theories with an Abelian gauge field are important topics with various physical applications. While an early renormalization-group-based study indicated that the direct transition from a fully ordered to a fully disordered state is continuous for N=1 and N>183, recently it was demonstrated that the transition is discontinuous for N=2. We quantitatively study the dependence on N of the degree of discontinuity of this transition. Our results suggest that the transition is discontinuous at least up to N=7. Furthermore, we demonstrate that, at increased coupling strength, the phase transitions of the neutral and charged sectors of the model split, which for N>2 yields a new phase with composite order. The transition from the composite-order phase to the fully disordered phase is then also discontinuous, at least for N=3 and N=4. Via a duality argument, this indicates that van der Waals–type interaction between directed loops may be responsible for the discontinuous phase transitions in these models. Published by the American Physical Society 2024

Numerical Exploration of a Network of Nonlocally Coupled Josephson Junction Spurred by Wien BridgeOscillators

This paper focuses on the numerical study of the collective dynamics of nonlocally coupled Josephson junctions (JJ) driven by Wien bridge oscillators (JJSWBOs). A single JJSWBO exhibits monostable and bistable chaotic behaviors, bistable period-3 oscillations, and a coexistence of regular and chaotic dynamics. To explore the network's collective dynamics, the local dynamics are set in a bistable regime, with initial conditions ensuring random distribution of units on these two types of behavior. Increasing the coupling strength transitions the network from complete incoherence to coherent traveling waves via a chimera state.

Versatile Method of Engineering the Band Alignment and the Electron Wavefunction Hybridization of Hybrid Quantum Devices.

Hybrid devices that combine superconductors (S) and semiconductors (Sm) have attracted great attention due to the integration of the properties of both materials, which relies on the interface details and the resulting coupling strength and wavefunction hybridization. However, until now, none of the experiments have reported good control of the band alignment of the interface, as well as its tunability to the coupling and hybridization. Here, the interface is modified by inducing specific argon milling while maintaining its high quality, e.g., atomic connection, which results in a large induced superconducting gap and ballistic transport. By comparing with Schrödinger-Poisson calculations, it is proven that this method can vary the band bending/coupling strength and the electronic spatial distribution. In the strong coupling regime, the coexistence and tunability of crossed Andreev reflection and elastic co-tunneling-key ingredients for the Kitaev chain-are confirmed. This method is also generic for other materials and achieves a hard and huge superconducting gap in lead and indium antimonide nanowire (Pb-InSb) devices. Such a versatile method, compatible with the standard fabrication process and accompanied by the well-controlled modification of the interface, will definitely boost the creation of more sophisticated hybrid devices for exploring physics in solid-state systems.

Exploration of the LHCb Pc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P_c$$\\end{document} states and possible resonances in a unitary coupled-channel model

We extend our previous study of the interactions of D¯(∗)Λc-D¯(∗)Σc(∗)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\bar{D}^{(*)} \\Lambda _c - \\bar{D}^{(*)}\\Sigma _c^{(*)}$$\\end{document} within an analytic, unitary, coupled-channel approach by including the J/ψp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J/\\psi p$$\\end{document} channel and performing fits to the J/ψp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J/\\psi p$$\\end{document} invariant mass distributions in the Λb0→J/ψpK-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Lambda _b^0 \\rightarrow J/\\psi p K^-$$\\end{document} decay by the LHCb Collaboration. We take into account the contributions of t-channel pseudoscalar and vector meson exchanges and u-channel baryon exchanges in this work, and a series of bound states and resonances with different spin-parities are dynamically generated. According to the results, four states have a significant impact on the physical observables, with two having a spin-parity of 1/2-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1/2^-$$\\end{document} and the other two having 3/2-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$3/2^-$$\\end{document}. These states can be associated with the LHCb hidden-charm pentaquarks. We further provide the coupling strength between each pole and different channels, which provides some insights on how to search for them in future experiments. Moreover, we also search for poles in higher partial waves up to J=7/2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J=7/2$$\\end{document} and find indications for the existence of several states with larger widths.

Suppressing Side‐Scattering on Laser‐Written Bragg Gratings for Back‐Reflection Engineering in Fibers

AbstractLaser direct writing (LDW) is versatile in structuring fibers with micro‐sized functional elements such as fiber Bragg grating (FBG) and backscattering centers by finely manipulating back and side scattering from laser‐induced refractive index modified (RIM) points. However, the side‐scattering is a lesser‐explored property in laser‐structured fibers. In this work, a concise physical model is established to understand the side‐scattering as a combined effect of microstructure and geometry of RIM points. Based on a single‐pulsed LDW method, the parametric decoupling between scattering loss (α) and coupling strength (κ) coefficients of FBGs is reported, whose cross‐section is customized to have a flattened ellipse with thoroughly positive RIM, enabling controllable reflectivity from −21.33 dB to −0.0018 dB while maintaining narrow bandwidth and low loss. Exemplarily, a designed FBG realizes ultra‐low loss of 0.008 dB with a resonance attenuation of 10.81 dB, exhibiting a record‐breaking κ/α of 2083. Using this FBG as the high‐reflective mirror of a home‐made bismuth‐doped fiber laser, narrow‐band lasing with a high optical signal‐to‐noise ratio of ≈43 dB is achieved, demonstrating flexibilities of the proposed approach in customizing both back‐ and side‐scattering in fibers and opening up wide opportunities for combining multifunctional components into optical fibers and realizing all‐fiber networks.

Synergy of Oxygen Octahedra Distortion and Polar Nanodomains Induced Emergent Electrocaloric Effect in NaNbO3-Based Ceramics.

High-performance electrocaloric materials are essential for the development of solid-state cooling technologies; however, the contradiction of the electrocaloric effect (ECE) and temperature span in ferroelectrics frustrates practical applications. In this work, through modulating oxygen octahedra distortion and short-range polar nanodomains with moderate coupling strength, an EC value of ΔT ∼ 0.30 K with an ultrawide temperature span of 85 K is obtained in the x = 0.04 composition [(0.88 - x)NaNbO3-0.12BaTiO3-xLiSbO3 (x = 0-0.06)]. The LiSbO3 dopant induces a P4bm-to-R3cH phase transition and intensifies the oxygen octahedra distortion degree, accompanied by the ferroelectric domain smashing into polar nanodomains. Also, LiSbO3 addition enhances the relaxation degree with a downshift of Tfd (ferroelectric-to-diffuse phase transition temperature) and TJ (temperature of the maximal current density value), and Tfd is shifted to near room temperature with an absence of TJ in x = 0.04. Local energy barriers induced by oxygen octahedra distortion inhibit the phase transition in conjunction with activation of short-range polar order switching under thermal stimuli, which is the underlying mechanism for an excellent EC performance for x = 0.04. This work not only clarifies that ferroelectrics with oxygen octahedra distortion and short-range polar order are expected to achieve remarkable EC performances but also provides a design strategy to seek emergent EC behaviors in complex oxygen-octahedra-distortion materials.

Tunable coupling of a quantum phononic resonator to a transmon qubit via galvanic-contact flip-chip architecture

A hybrid system with tunable coupling between phonons and qubits shows great potential for advancing quantum information processing. In this work, we demonstrate strong and tunable coupling between a surface acoustic wave resonator and a transmon qubit based on the galvanic-contact flip-chip technique. The coupling strength varies from 2π× 7.0 to −2π× 20.6 MHz, which is extracted from different vacuum Rabi oscillation frequencies. The phonon-induced ac Stark shift of the qubit at different coupling strengths is also shown. Our approach offers a good experimental platform for exploring quantum acoustics and hybrid systems.

Tracking EEG network dynamics through transitions between eyes-closed, eyes-open, and task states

Our study aimed to verify the possibilities of effectively applying chronnectomics methods to reconstruct the dynamic processes of network transition between three types of brain states, namely, eyes-closed rest, eyes-open rest, and a task state. The study involved dense EEG recordings and reconstruction of the source-level time-courses of the signals. Functional connectivity was measured using the phase lag index, and dynamic analyses concerned coupling strength and variability in alpha and beta frequencies. The results showed significant and dynamically specific transitions regarding processes of eyes opening and closing and during the eyes-closed-to-task transition in the alpha band. These observations considered a global dimension, default mode network, and central executive network. The decrease of connectivity strength and variability that accompanied eye-opening was a faster process than the synchronization increase during eye-opening, suggesting that these two transitions exhibit different reorganization times. While referring the obtained results to network studies, it was indicated that the scope of potential similarities and differences between rest and task-related networks depends on whether the resting state was recorded in eyes closed or open condition.

Aided design and molecular regulatory mechanism of non-fused ring acceptors in the framework of A-D1-D2-A molecular systems

Non-fused ring acceptors (NFRAs) have garnered significant attention due to their low cost, ease of synthesis, and high efficiency. Molecules with asymmetric structures can improve molecular stacking and effectively reduce non-radiative energy loss. So, the asymmetric A-D1-D2-A series NFRAs (DPCT-4F and DPCT-4Cl) were selected as the research objects, and four acceptors (DPCT-D1∼DPCT-D4) were designed using end-capped modification strategies. Theoretical simulations were conducted on the ground and excited state characteristics of DPCT series molecules, and the electron mobility of the dimers formed by these acceptors was calculated. It was found that the simulated energy levels, energy gaps, absorption spectra and open-circuit voltages of original molecules are consistent with the trends in the experiment, ensuring the accuracy of the calculation method. Moreover, the nearly equal bond lengths of the developed compounds and the original molecules at the corresponding positions indicate that end-capping modification strategies have little effect on the molecular bond lengths. However, the instability of C-C single bond results in an increased dihedral angle between dipyran and cyclopentadithiophene. Among these designed molecules, DPCT-D1 and DPCT-D2, modified with -CN/-NO2 functional groups, outperform the reference molecules regarding energy gap, molecular descriptors, absorption spectrum, and exciton binding energy. This demonstrates the superiority of functional group substitution strategies with strong electron-withdrawing ability. Introducing thiophene units enables DPCT-D4 molecule to achieve a higher open-circuit voltage, dipole moment and light capture ability. Additionally, all the designed molecules exhibit higher electron mobility than DPCT-4F. DPCT-D1 shows even higher mobility than the better-performing reference molecule DPCT-4Cl due to its greater electronic coupling strength and lower reorganization energy. Overall, most tailored molecules, particularly DPCT-D1, exhibit superior performance in most critical parameters compared to the reference molecules, demonstrating the design strategy's effectiveness and offering worthwhile theoretical instruction for developing high-performance acceptors.

Anisotropic magnon frequency comb based on antiferromagnetic bimerons

The interaction between propagating magnons and topological spin textures is attracting a lot of recent attention from the magnonic community. It has been shown that the three-wave mixing between magnons and breathing skyrmion can induce the magnon frequency comb (MFC) with equidistant coherent peaks. However, a magnetic bimeron is a nontrivial spin texture and is regarded as the counterpart of the skyrmion in easy-plane magnets with Dzyaloshinskii–Moriya interaction, which allows anisotropic magnon propagations. This raises the question of whether the nonlinear interaction between magnons and bimerons can generate an MFC. If so, how does the direction of magnon propagation affect the characteristics of the MFC? In this Letter, we demonstrate that the three-wave mixing between propagating magnons and locally breathing bimerons can induce a terahertz MFC in easy-plane antiferromagnets. Micromagnetic simulations reveal that the three-wave coupling strength weakly depends on the driving frequency, but it strongly relies on the propagation direction of incident magnons. Our findings uncover the anisotropic nature of MFC in bimeron structures, which may have potential applications for ultrafast magnonic devices with spectroscopy, metrology, and sensing functionalities.

Influence of atomistic features in plasmon-exciton coupling and charge transfer driven by a single molecule in a metallic nanocavity.

When an organic molecule is placed inside a plasmonic cavity formed by two metallic nanoparticles (MNP) under illumination, the electronic excitations of the molecule couple to the plasmonic electromagnetic modes of the cavity, inducing new hybrid light-matter states called polaritons. Atomistic abinitio methods accurately describe the coupling between MNPs and molecules at the nanometer scale and allow us to analyze how atomistic features influence the interaction. In this work, we study the optical response of a porphine molecule coupled to a silver nanoparticle dimer from first principles, within the linear-response time-dependent density functional theory framework, using the recently developed Python Numeric Atomic Orbitals implementation to compute the optical excitations. The optical spectra show the splitting of the resonances of the plasmonic dimer and the molecule into two distinct polaritons, a characteristic feature of the strong light-matter coupling regime. Our results stress the importance of atomistic features, such as the gap configuration in determining the plasmon-exciton coupling strength and in the emergence of molecule-mediated charge-transfer plasmon (CTP) resonances at lower frequencies. Moreover, we show that the strength of the CTP resonance can be tuned by shifting the alignment of the molecular energy levels with respect to the Fermi level of the MNPs.

Bilinear Fronsdal currents in the AdS4 higher-spin theory

We analyse higher-spin theory with general coupling constant η at the second order, focusing on the gauge non-invariant vertices Υ(ω, ω), Υ(Ω, ω, C) and Υ(ω, C), that are shown to generate nontrivial currents in the Fronsdal equations. Explicit expressions for the currents are found in the frame-like formalism counterpart of the TT gauge worked out in the paper. The nonlinear higher-spin theory is shown to generate all types of Metsaev’s currents with the coupling constants manifestly expressed via the complex coupling constant η of the higher-spin theory. It is shown that all currents in the higher-spin theory are conformal in the TT gauge except for those bilinear in the higher-spin gauge fields ω.

New sesquineolignan glycoside isomers from the aerial parts of Leonurus japonicus and their absolute configurations

The acid water-soluble fraction of the 95% EtOH extract of Leonurus japonicus exhibited significant anti-inflammatory activity by suppressing the p-ERK/ERK ratio and iNOS expression. A further phytochemical investigation of this acid water-soluble fraction led to the isolation of three previously undescribed sesquineolignan glycosides, leolignosides A–C (1–3), and their planar structures were elucidated using HR-ESI-MS and 1D and 2D NMR. To determine the complicated absolute configuration of sesquineolignan glycosides, coupling constants, NOESY data, empirical rules, enzymatic hydrolysis, and ECD data were comprehensively used. These isolated compounds were also screened for anti-inflammatory activity. Encouragingly, leolignosides A–C all suppressed LPS-induced NO overproduction in RAW 264.7 macrophages. The aglycone (3a) of leolignoside C was chosen for further investigation for its activity and the available amount. Similar to the acid water-soluble fraction, compound 3a inhibited NO overproduction and decreased the p-ERK/ERK and p-NF-κB/NF-κB ratios, indicating that 3a may exert anti-inflammatory effects through the ERK/NF-κB signaling pathway.

Role of complexity on the minimal deformation of black holes

Abstract We investigate spherically symmetric classes of anisotropic
solutions within the realm of a schematic gravitational decoupling scheme, primarily decoupling through minimal geometric
deformation, applied to non-rotating, ultra-compact,
self-gravitational fluid distributions. In this respect, we employ
the minimal complexity factor scheme
to generate physically realistic models for
anisotropic matter distributions, using a well-behaved model. The zero-complexity factor condition enables us to
determine the deformation function for solving the decoupled system.
We explore all the structure-defining scalar variables, such as
density inhomogeneity, strong energy
condition, density homogeneity, and the complexity factor (an alloy of
density inhomogeneity and pressure anisotropy) for the decoupling
constant ranging between $0$ and $1$. We observe that the anisotropy vanishes when the coupling constant is set to unity. This finding holds significance as it implies that, in the context of a zero-complexity factor approach, an anisotropic matter distribution becomes perfect without requiring any isotropy requirements. This work effectively explored the impact of complexity on the composition of self-gravitational stellar distributions. This effective approach enables the development of new, physically realistic isotropic stellar models for anisotropic matter distributions. Additionally, our findings indicate that the complexity factor in static, spherically symmetric self-gravitational objects can significantly affect the nature of the matter distribution within these systems. It is concluded that the minimally deformed Durgapal-IV model features an increasing pressure profile, and the local anisotropy of pressure vanishes throughout the model under complexity-free conditions.

Atom-magnon entanglement in a coupled cavity-magnon atom-optomechanical system

We propose an alternative way to realize macroscopic entanglement between an atomic ensemble and ferrimagnetic magnons in a hybrid cavity-magnon atom-optomechanics, in which a microwave cavity couples to the magnons via magnetic dipole interaction, and simultaneously couples to a standard optomechanical cavity with an ensemble of two-level atoms. We show that in experimental feasible parameters, the optomechanical entanglement can be transferred to the bipartite subsystems, which makes it possible to generate the macroscopic atom-magnon entanglement and genuine tripartite entanglement. We mainly analyze the effects of coupling strengths on the efficiency of the entanglement transfer and the generation of the atom-magnon entanglement. We find that by selecting appropriate coupling strengths, both the degree of the atom-magnon entanglement and its robustness against the environmental temperature are enhanced significantly.

Strong radiative coupling between two quantum emitters with arbitrary mutual orientation via a silver nano-arc

Strong radiative coupling realizes coherent exchange of single excitation between two quantum emitters, while their dipole orientation influences the coupling strength in anisotropic environments. We propose a silver nano-arc with arbitrary radian which can support two hot spots of electric field with radian-independent resonant wavelength. Two quantum emitters resonant with the cavity mode, embedded inside the two hot spots and oriented along the nano-arc axis, can realize strong radiative coupling, verified by the large splitting and anti-crossing behavior in the spectrum and the population oscillation in the time domain. All these signatures of strong radiative coupling are robust against the nano-arc’s curvature. Our work provides a flexible approach to realize strong radiative coupling between two quantum emitters with arbitrary mutual orientation and facilitates quantum information processing.

The evolution of cooperation and global synchronization in the evolutionary Kuramoto dilemma combined with the prisoner's dilemma

In this work, we have studied the evolution of the cooperation and the global synchronization on the Kuramoto model upon random networks with two games, in which one is the evolutionary Kuramoto dilemma and the other is the weak prisoner's dilemma. Agents can gain their payoffs from these two games synchronously. In the evolutionary Kuramoto game, cooperators prefer the formation of local synchronization but pay less cooperative cost. Cooperators in weak prisoner's dilemma can form cooperator clusters because of the network reciprocity. Combining these two games shows a mutual promotion effect upon the order of the global synchronization but a competition effect on the cooperation level. The global synchronization begins to rise only when most agents choose cooperation. It is manifested by the fact that the optimal coupling strength for the highest cooperation level is smaller than that for the highest synchronization level. The high cooperation cost makes defection the most advantageous strategy when the coupling strength reaches rather high, which diminishes the effect of cooperator clusters, and ultimately results in the absence of both cooperators and global synchronization. When agents have more neighbors in the random network, it is observed that cooperation is consistently hindered unless the coupling strength is relatively small. Additionally, there is always an optimal average degree that allows for global synchronization.

Non-universality Relationships for Charged Higgs Boson Yukawa Couplings in the Two Higgs Doublet Model Type III

In the context of the two Higgs doublet model type III with flavor-changing neutral currents at the tree level, I obtain non-universality relationships of charged Higgs boson Yukawa coupling constants by calculating the widths of the pure leptonic decays of the tau lepton τ→eν¯eντ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ au \\rightarrow e \\bar{\ u }_e \ u _\ au$$\\end{document} and τ→μν¯μντ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ au \\rightarrow \\mu \\bar{\ u }_\\mu \ u _\ au$$\\end{document}. To this end, I first calculate these total widths by including the effects of the exchanges of the Higgs boson H-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$H^-$$\\end{document} and the gauge boson W-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$W^-$$\\end{document}, with the purpose to obtain the flavor-violating contribution ΔlH-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta _l^{H^-}$$\\end{document} and then to calculate the fraction ΔμH-/ΔeH-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta _\\mu ^{H^-}/\\Delta _e^{H^-}$$\\end{document}. By writing this fraction in terms of the experimental and electroweak standard model branching ratios of these decays and assuming that flavors of neutrino and antineutrino in the final state are defined but unknown, I obtain fractions of charged Higgs boson Yukawa coupling constants that differ from one. These fractions establish non-universality relationships associated with the scalar interaction in contrast to the universality relationships associated with the electroweak interaction.

Inter-layer coupling strength in lipid bilayer can control the size of lipid domains

Inter-layer coupling strength in lipid bilayer can control the size of lipid domains

Vortex phase diagram and transition in (Bi1.6Pb0.4Sr2Ca2Cu3O10-δ)1-x(SnO2)x superconductors

The superconducting vortex phase diagram of (Bi1.6Pb0.4Sr2Ca2Cu3O10-δ)1-x(SnO2)x ceramics, where x = 0, 0.002, 0.004, 0.006, 0.008, and 0.010, was investigated using resistivity measurement under magnetic fields. If the value of the offset critical temperature (Tc,offset) monotonously decreased on the SnO2-added samples, then the mean-field critical temperature (Tmf) would slightly improve on the x = 0.002 sample. The excess conductivity of all samples was analyzed based on the Aslamazov–Larkin and Lawrence–Doniach models. The c-axis coherence length at 0 K (ξc(0)) and the interlayer coupling strength were optimized on the x = 0.002 sample. The activation energy (U0) calculated using the Arrhenius model was also increased, and the maximum for the x = 0.002 sample was reached. The upper critical field (Bc2) deduced using the Werthamer–Helfand–Hohenberg model was also enhanced for the x = 0.002 sample. The small bundle field (Bsb), large bundle field (Blb), irreversibility field (Birr), and Bc2 were combined for the vortex phase (B-T) diagram of the x = 0.000 and x = 0.002 samples. All pinning regimes of the x = 0.002 sample were extended, clearly revealing the improvements in the flux pinning properties in that sample.