Heavy States Research Articles

Oscillator design for high efficiency DC-DC of micro direct methanol fuel cell

This paper develops a novel oscillator with wide output frequency range, continuous frequency adoption, anti-electromagnetic interference (EMI), and high precision in order to achieve the high energy conversion efficiency of DC-DC for micro direct methanol fuel cell (μDMFC). The oscillator employs the state of art including frequency jitter, slope compensation, and digital trimming to perform the load mode control and detection module, thus linearly adjusting the operating frequency and modulation according to the load. Based on the 0.18 μm microelectronics process, the transient output of the presented oscillator during continuously turning on exports a stable voltage square wave. The jitter frequency ranges only about −1.66% to +4.3% of the base frequency. Moreover, the oscillator can adjust the typical output frequency linearly from 100 kHz to 1 MHz continuously based on the light or heavy load state. The oscillator yields stable performance under EMI with the jittering rate ranges from −31.82% to 36.2%. The quantitative results validates the wide frequency range, continuous frequency adoption, anti-EMI, and high precision of the oscillator. The oscillator solves the low energy conversion efficiency of the μDMFC DC-DC. The oscillator will achieve high energy conversion efficiency and stable output voltage of μDMFC for practical application.

Open-quantum-systems approach to in-medium heavy quarkonium dynamics

Heavy quarkonium continues to play a central role in the study of nuclear matter under extremes of temperature and density in relativistic heavy-ion collisions. In this talk I report on recent developments in the theoretical description of quarkonium in-medium dynamics using the open-quantum systems approach. Not only does it provide a clear interpretation of the imaginary part of the complex heavy-quark potential but also reveals that a subtle interplay between screening and wavefunction decoherence is responsible for the melting of heavy quarkonium states.

Spectroscopic behavior of fully heavy tetraquarks

Stimulated by the observation of the X(6900) from LHCb in 2020 and the recent results from CMS and ATLAS in the di-J/psi invariant mass spectrum, in this work we systematically study all possible configurations for the ground states of fully heavy tetraquark in the constituent quark model. By our calculation, we present their spectroscopic behaviors including binding energy, lowest meson–meson thresholds, specific wave function, magnetic moment, transition magnetic moment, radiative decay width, rearrangement strong width ratio, internal mass contributions, relative lengths between (anti)quarks, and the spatial distribution of four valence (anti)quarks. We cannot find a stable S-wave state for the fully heavy tetraquark system. We hope that our results will be valuable to further experimental exploration of fully heavy tetraquark states.

Radiative and semileptonic decay widths of heavy ground state baryons in diquark model

Radiative and semileptonic decay widths of heavy ground state baryons in diquark model

Effects of complex sulphur substrates on sludge bioleaching to improve heavy metal removal and microbial community diversity

In this study, H2S was used as a partial replacement nutrient substrate for sludge bioleaching. The effects of different combinations of H2S/sludge load and monomeric sulphur on heavy metal removal and microbial communities were investigated. Changes in pH, oxidation-reduction potential (ORP), SO42− concentration, heavy metal removal, and the content of heavy metal states during bioleaching were investigated, and community diversity analysis was performed. Daily introduction of H2S three times (at an interval of 8 h) at a gas flow rate of 2 ml/min and an H2S/sludge load of 15 ml/L with 5 g/L FeSO4·7H2O and 2 g/L monomeric sulphur as a nutrient substrate significantly accelerated both the bioleaching process and the pH drop in the sludge system, promoted the production of SO42−, and maintained a higher redox potential. The combination of H2S and monomeric sulphur had a significant effect on the leaching of heavy metals. Compared with the experimental group containing only H2S or monomeric sulphur, the removal rates of Zn, Ni, Pb, and Cr increased by 4.63%/13.8%, 8.5%/20.07%, 3.84%/9.5%, and 4.24%/8.02% respectively, while promoting the transformation of various heavy metal states to labile states, improving heavy metal stability, and reducing sludge ecotoxicity. High-throughput sequencing analysis showed that introducing the H2S gaseous matrix accelerated the decreasing trend of species number, bacterial abundance, and community diversity in the sludge system, promoting Proteobacteria as the dominant phylum, Acidithiobacillus, Metallibacterium, and Thiomonas as the dominant genera, and improving the bioleaching treatment effect.

Prediction of charmed-bottom pentaquarks in quark model

Inspired by the fully heavy tetraquark states reported by the LHCb, ATLAS and CMS Collaborations, we perform a systematical investigation of the low-lying fully heavy pentaquark systems composed of charm and bottom quarks (anti-quark) in the chiral quark model. With the help of the channel-coupling, we obtain several fully heavy pentaquark candidates, which are ccccbar{b} and bbbbbar{c} systems with J^P = 1/2^- and 3/2^-, cccbbar{c}, bbbcbar{b}, cccbbar{b} and bbbcbar{c} systems with J^P = 5/2^-. The binding energies of these states are all below 10 MeV and the root mean square (RMS) are around 1.8 fm, which indicates that these states are likely to be molecular states. These predicted exotic states may provide new ideas for experimental searches and we expect more experimental and theoretical researches to study and understand the fully heavy states in future.

Kondo interaction in FeTe and its potential role in the magnetic order

Finding d-electron heavy fermion states has been an important topic as the diversity in d-electron materials can lead to many exotic Kondo effect-related phenomena or new states of matter such as correlation-driven topological Kondo insulator. Yet, obtaining direct spectroscopic evidence for a d-electron heavy fermion system has been elusive to date. Here, we report the observation of Kondo lattice behavior in an antiferromagnetic metal, FeTe, via angle-resolved photoemission spectroscopy, scanning tunneling spectroscopy and transport property measurements. The Kondo lattice behavior is represented by the emergence of a sharp quasiparticle and Fano-type tunneling spectra at low temperatures. The transport property measurements confirm the low-temperature Fermi liquid behavior and reveal successive coherent-incoherent crossover upon increasing temperature. We interpret the Kondo lattice behavior as a result of hybridization between localized Fe 3dxy and itinerant Te 5pz orbitals. Our observations strongly suggest unusual cooperation between Kondo lattice behavior and long-range magnetic order.

Anisotropic Behavior of S-Wave and P-Wave States of Heavy Quarkonia at Finite Magnetic Field

We studied the effect of momentum space anisotropy on heavy quarkonium states using an extended magnetized effective fugacity quasiparticle model (EQPM). Both the real and imaginary part of the potential has been modified through the dielectric function by including the anisotropic parameter ξ. The real part of the medium-modified potential becomes more attractive in the presence of the anisotropy and constant magnetic field. The binding energy of the 1S, 2S, and 1P quarkonium states including anisotropy effects for both the oblate and the isotropic case were studied. We find that the binding energy of QQ¯ states becomes stronger in the presence of anisotropy. However, the magnetic field is found to reduce the binding energy. The thermal width of the charmonium and bottomonium 1S states has been studied at constant magnetic field eB=0.3 GeV2 for isotropic and prolate cases. The effect of magnetic field on the mass spectra of the 1P state for the oblate case was also examined. The dissociation temperature for the 1S, 2S, and 1P states of charmonium and bottomonium has been determined to be higher for the oblate case with respect to the isotropic case.

Heavy quarkonium with finite three momentum near Tc

We investigate the non-trivial 3-momentum effects on the masses of heavy quarkonium states that are moving in a hot medium using QCD sum rules. For all charmonium states, we observe a negative mass shift near $T_c$ that is less than 3$\%$ at a momentum of 1$\rm{GeV}$. Specifically, we first investigate the difference between the longitudinal and transverse modes of both $J/\psi$ and $\chi_{c1}$. We find that the transverse mode of the $J/\psi$ experiences larger modification than the longitudinal mode, while the $\chi_{c1}$ has the opposite behavior. By comparing the $\eta_c$ and $\chi_{c0}$, and also the unpolarized $J/\psi$ and $\chi_{c1}$, we recognize that the P-wave particles have stronger momentum dependencies on their masses than the S-wave ones. We also find $\Upsilon$(1S) has negligible 3-momentum dependence compared to the charmonium states, e.g. less than 0.01$\%$ even at 1.4$T_c$ and at a momentum of 4$\rm{GeV}$.

Introducing shrinkage in heavy-tailed state space models to predict equity excess returns

AbstractWe forecast excess returns of the S &P 500 index using a flexible Bayesian econometric state space model with non-Gaussian features at several levels. More precisely, we control for overparameterization via global–local shrinkage priors on the state innovation variances as well as the time-invariant part of the state space model. The shrinkage priors are complemented by heavy tailed state innovations that cater for potential large breaks in the latent states, even if the degree of shrinkage introduced is high. Moreover, we allow for leptokurtic stochastic volatility in the observation equation. The empirical findings indicate that several variants of the proposed approach outperform typical competitors frequently used in the literature, both in terms of point and density forecasts.

Triangular Kondo lattice in YbV6Sn6 and its quantum critical behavior in a magnetic field

We report on the magnetization, specific heat, and electrical resistivity for a newly discovered heavy-fermion (HF) compound, ${\mathrm{YbV}}_{6}{\mathrm{Sn}}_{6}$, which is crystallized in a hexagonal ${\mathrm{HfFe}}_{6}{\mathrm{Ge}}_{6}$-type structure, highlighted by the stacking of the triangular ytterbium sublattice and kagome vanadium sublattice. Above 2 K, ${\mathrm{YbV}}_{6}{\mathrm{Sn}}_{6}$ shows typical HF properties due to the Kondo effect on the Kramers doublet of ${\mathrm{Yb}}^{3+}$ ions in the crystalline electric field. A remarkable magnetic ordering occurs at ${T}_{\mathrm{N}}=0.40$ K in zero field, while a weak external field suppresses the ordering and induces non-Fermi-liquid behavior. In strong magnetic field, the compound shows a heavy Fermi-liquid state. ${\mathrm{YbV}}_{6}{\mathrm{Sn}}_{6}$ is represented as one of the few examples of Yb-based HF compounds hosting a triangular Kondo lattice on which a magnetic field induces quantum criticality near zero temperature.

Course keeping control for very large ship using hyperbolic tangent function based on nonlinear decoration technique

To solve the problems of difficult course keeping, high energy output, and large wear of very large ships under different sea conditions, a robust controller combining the closed-loop gain shaping algorithm and nonlinear decoration is proposed in this paper. Firstly, a linear controller is designed by using the third-order closed-loop gain shaping algorithm and takes the hyperbolic tangent function as the nonlinear decoration of the controller output, and the robustness of the system is proved by H∞ robust control theory. Secondly, taking ‘Vale Brasil’, an ore carrier with a displacement of 400,000 tons, as the test plant. The nonlinear Nomoto model and nonlinear Norrbin model were established, which were compared with the control effect from the existing controller. Thirdly, simulation experiments were carried out under normal sea state and heavy sea state to prove the effectiveness. The results indicate that the proposed control strategy can achieve the required course faster, and enhances the smoothness of rudder angle actuation compared with the existing controller. It can maintain good control ability under different sea conditions. The proposed controller has the advantages of simple parameter adjustment, better robustness, less energy consumption, and reduced rudder angle. It is more in line with engineering practice and increases ship operation benefits.

Fractional Effective Quark-Antiquark Interaction in Symplectic Quantum Mechanics

Considering the formalism of symplectic quantum mechanics, we investigate a two-dimensional nonrelativistic strong interacting system, describing a bound heavy quark-antiquark state. The potential has a linear component that is analyzed in the context of generalized fractional derivatives. For this purpose, the Schrödinger equation in phase space is solved with the linear potential. The ground state solution is obtained and analyzed through the Wigner function for the meson c c ¯ . One basic and fundamental result is that the fractional quantum phase-space analysis gives rise to the confinement of quarks in the meson, consistent with experimental results.

Pairing of holes by confining strings in antiferromagnets

In strongly correlated quantum materials, the behavior of charge carriers is dominated by strong electron-electron interactions. These can lead to insulating states with spin order, and upon doping to competing ordered states including unconventional superconductivity. The underlying pairing mechanism remains poorly understood however, even in strongly simplified theoretical models. Recent advances in quantum simulation allow to study pairing in paradigmatic settings, e.g. in the t-Jt−J and t-J_zt−Jz Hamiltonians. Even there, the most basic properties of paired states of only two dopants, such as their dispersion relation and excitation spectra, remain poorly studied in many cases. Here we provide new analytical insights into a possible string-based pairing mechanism of mobile holes in an antiferromagnet. We analyze an effective model of partons connected by a confining string and calculate the spectral properties of bound states. Our model is equally relevant for understanding Hubbard-Mott excitons consisting of a bound doublon-hole pair or confined states of dynamical matter in lattice gauge theories, which motivates our study of different parton statistics. Although an accurate semi-analytic estimation of binding energies is challenging, our theory provides a detailed understanding of the internal structure of pairs. For example, in a range of settings we predict heavy states of immobile pairs with flat-band dispersions - including for the lowest-energy dd-wave pair of fermions. Our findings shed new light on the long-standing question about the origin of pairing and competing orders in high-temperature superconductors.

Fat b-jet analyses using old and new clustering algorithms in new Higgs boson searches at the LHC

We compare different jet-clustering algorithms in establishing fully hadronic final states stemming from the chain decay of a heavy Higgs state into a pair of the 125 GeV Higgs boson that decays into bottom-antibottom quark pairs. Such 4b events typically give rise to boosted topologies, wherein b{bar{b}} pairs emerging from each 125 GeV Higgs boson tend to merge into a single, fat b-jet. Assuming large hadron collider (LHC) settings, we illustrate how both the efficiency of selecting the multi-jet final state and the ability to reconstruct from it the masses of all Higgs bosons depend on the choice of jet-clustering algorithm and its parameter settings. We indicate the optimal choice of clustering method for the purpose of establishing such a ubiquitous beyond the SM (BSM) signal, illustrated via a Type-II 2-Higgs Doublet Model (2HDM).

Pressure-induced Structural Phase Transition and New Superconducting Phase in UTe2

We report on the crystal structure and electronic properties of the heavy fermion superconductor UTe2 at high pressure up to 11 GPa, as investigated by X-ray diffraction and electrical resistivity experiments. The X-ray diffraction measurements under high pressure using a synchrotron light source reveal anisotropic linear compressibility of the unit cell up to 3.5 GPa, while a pressure-induced structural phase transition is observed above PO–T ∼ 3.5–4 GPa at room temperature, where the body-centered orthorhombic crystal structure with the space group Immm changes into a body-centered tetragonal structure with the space group I4/mmm. The molar volume drops abruptly at PO–T, while the distance between the first-nearest neighbor of U atoms, dU–U, increases, implying a switch from the heavy electronic states to the weakly correlated electronic states. Surprisingly, a new superconducting phase at pressures higher than 7 GPa was detected at Tsc > 2 K with a relatively low upper-critical field, Hc2(0). The resistivity above 3.5 GPa, thus, in the high-pressure tetragonal phase, shows a large drop below 230 K, which may also be related to a considerable change from the heavy electronic states to the weakly correlated electronic states.

Spectroscopic Study of $$\pmb {\varOmega _{cc}}$$, $$\pmb {\varOmega _{cb}}$$ and $$\pmb {\varOmega _{bb}}$$ Baryons

In this paper, we presented the mass spectra of the doubly heavy $\Omega$ baryons containing one light (strange) quark and two heavy (charm and bottom) quarks. Our predicted masses can be consider to determine the $J^p$ value for the resonances detected by experimental facilities in future. The masses of ground excited states (1S-6S, 1P-3P, 1D-2D, 1F-2F) are calculated for all possible $J^p$ values, using the Hypercentral Constituent Quark Model (hCQM), by employing screened potential as confining potential with color-Coloumb potential. Regge trajectories are also plotted in $(J, M^2)$ plane for natural and unnatural parities. Doubly heavy Omega states are not declared yet by any experimental facility. We compared our results to the predictions gained from other theoretical approaches, and we found that our predictions are quite close to those of them. Other properties such as magnetic moment (for spin state $\frac{1}{2}$ and $\frac{3}{2}$) and radiative decay width are calculated using the enuerated masses.

Massive color-kinematics duality and double-copy for Kaluza-Klein scattering amplitudes

We study the structure of scattering amplitudes of massive Kaluza-Klein (KK) states under toroidal compactification. We present a shifting method to quantitatively derive the scattering amplitudes of massive KK gauge bosons and KK gravitons from the corresponding massless amplitudes in the noncompactified higher dimensional theories. With these we construct the massive KK scattering amplitudes by extending the double-copy relations of massless scattering amplitudes within the field theory framework, including both the BCJ and CHY methods, and build up their connections to the massive KK KLT relations. We present the massive BCJ-type double-copy construction of the N-point KK gauge boson/graviton scattering amplitudes, and as the applications we derive explicitly the four-point KK scattering amplitudes as well as the five-point KK scattering amplitudes. We further study the nonrelativistic limit of these massive scattering amplitudes with the heavy external KK states and discuss the impact of the compactified extra dimensions on the low energy gravitational potential. Finally, we analyze the four-point and N-point mass spectral conditions and newly propose a novel group theory approach to prove that only the KK theories under toroidal compactification can satisfy these conditions for directly realizing massive double-copy in the field theory framework.

Strictly regulated cannabis retail models with state control can provide lessons in how jurisdictions can regulate THC.

Strictly regulated cannabis retail models with state control can provide lessons in how jurisdictions can regulate THC.

Assessment of the status of improved F&E trachoma control practices among children of agro-pastoralists in Southern Ethiopia: a mixed design survey using theory of triadic influences

BackgroundEthiopia is one of the countries with heavy trachoma burdens states globally. More than 75 million people in Ethiopia live in the trachoma endemic zones. Most populations with neglected tropical diseases (NTDs) live in hard-to-reach residences because of landscape and socio-cultural variances. This survey assessed the status of improved Face hygiene and Environmental cleanliness (F&E) trachoma control practices in children 1–9 years of age.MethodsA mixed-method study design was applied concurrently. Enumeration was done through interviews using the standard tool and observational technique. Focus Group discussions (FGDs) and Key informant Interviews (KIIs) were used to conduct the qualitative arm. Confounders were controlled by modeling with multivariable logistic regression.ResultsFor the Quantitative survey: The response rate was 99.8% of participants. The proportion with improved practice was 8%. About 13.9% of a child washed their faces and were visibly clean. About 15.2% of the households had an observable clean environment. High Wealth index, Perceived ability, knowledge about trachoma transmission from person to person, and stance toward preventive behavior were associated with improved practices. The odds of having improved F&E practice were 67% lower for those who reported positive normative preventive behavior than negatives. Qualitative arm: Some key informants reported village dwellers’ shortage of basic knowledge; attitude and behavioral change for improved hygienic practices are the challenges. Inhabitants, including elder children, are aware of the hygiene issue though they do not practice it or have no intention to practice it.ConclusionsImproved F&E practices were much lower in the study region than the regional plan to achieve.