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Y. P. Wang

Publications and source records attributed to Y. P. Wang.

At least 19 recordsLinked to original sources
arXiv2026

Configuration-interaction time-dependent density functional theory for nuclear dynamics

A configuration-interaction time-dependent density functional theory (CI-TDDFT) for nuclear dynamics is developed. In this framework, the correlated nuclear many-body wave function is expanded in terms of time-dependent many-particle configurations built from a common set of orthonormal single-particle states. The equations of motion for both the expansion coefficients and the single-particle states are derived self-consistently using the Dirac-Frenkel time-dependent variational principle. This formulation extends conventional time-dependent density functional theory (TDDFT) by incorporating configuration mixing and beyond-mean-field correlations, while preserving energy and particle-number conservation. As an illustrative application, the method is implemented using the relativistic point-coupling functional PC-PK1 in the particle-hole channel and a monopole pairing interaction in the particle-particle channel, and is applied to the study of isoscalar giant monopole resonance in $^{58}$Ni and $^{60}$Ni. Numerical tests show that both the total energy and particle number are conserved, with relative deviations within $4\times 10^{-4}$ during the time evolution. Compared with conventional TDDFT, CI-TDDFT yields broader strength distributions for giant monopole resonances while keeping the main peak positions close to those from TDDFT. This broadening is associated with configuration mixing in the valence space and suggests a coupling of the monopole oscillation to additional collective degrees of freedom. These results demonstrate the potential of CI-TDDFT as a quantum, microscopic beyond-mean-field framework for nuclear dynamics.

nucl-th↗
arXiv2025

Tilted-axis-cranking covariant density functional theory for the high-spin spectroscopy in $^{69}$Ga

The tilted-axis-cranking covariant density functional theory is applied to investigate the three newly-observed positive-parity bands SI, SII, and SIII in $^{69}$Ga. The energy spectra and angular momenta are calculated and compared with the experimental data. For the yrast band SI, pairing correlations play a crucial role for the states with spin $I\leq 23/2\hbar$. The bands SII and SIII are suggested to be signature partner bands with positive and negative signatures, respectively. The transition probabilities $B(E2)$ for these bands are predicted, and await further experimental verification. By analyzing the angular momentum alignments microscopicly, it is revealed that the $g_{9/2}$ protons and neutrons play an important role in the description of the collective structure of $^{69}$Ga.

nucl-th↗
arXiv2024

Emergence of High-Order Deformation in Rotating Transfermium Nuclei: A Microscopic Understanding

The rotational properties of the transfermium nuclei are investigated in the full deformation space by implementing a shell-model-like approach in the cranking covariant density functional theory on a three-dimensional lattice, where the pairing correlations, deformations, and moments of inertia are treated in a microscopic and self-consistent way. The kinematic and dynamic moments of inertia of the rotational bands observed in the transfermium nuclei $^{252}$No, $^{254}$No, $^{254}$Rf, and $^{256}$Rf are well reproduced without any adjustable parameters using a well-determined universal density functional. It is found for the first time that the emergence of the octupole deformation should be responsible for the significantly different rotational behavior observed in $^{252}$No and $^{254}$No. The present results provide a microscopic solution to the long-standing puzzle on the rotational behavior in No isotopes, and highlight the risk of investigating only the hexacontetrapole ($β_{60}$) deformation effects in rotating transfermium nuclei without considering the octupole deformation.

nucl-th↗
arXiv2024

Abnormal Bifurcation of the Double Binding Energy Differences and Proton-Neutron Pairing: Nuclei Close to $N=Z$ Line from Ni to Rb

The recently observed abnormal bifurcation of the double binding energy differences $δV_{pn}$ between the odd-odd and even-even nuclei along the $N=Z$ line from Ni to Rb has challenged the nuclear theories. To solve this problem, a shell-model-like approach based on the relativistic density functional theory is established, by treating simultaneously the neutron-neutron, proton-neutron, and proton-proton pairing correlations both microscopically and self-consistently. Without any \textit{ad hoc} parameters, the calculated results well reproduce the observations, and the mechanism for this abnormal bifurcation is found to be due to the enhanced proton-neutron pairing correlations in the odd-odd $N=Z$ nuclei, compared with the even-even ones. The present results provide an excellent interpretation for the abnormal $δV_{pn}$ bifurcation, and provide a clear signal for the existence of the proton-neutron pairing correlations for nuclei close to the $N=Z$ line.

nucl-th↗
arXiv2024

The 25th anniversary for nuclear chirality

The brief history for the prediction of the nuclear chirality is provided. The theoretical and experimental investigations of the nuclear chirality are reviewed, including the verification of chiral doublet bands, the chiral conundrum and its resolution, and the prediction and observation of the multiple chiral doublets (M$χ$D). Some recent theoretical progresses are highlighted, including the chiral collective Hamiltonian, the A-plot and the K-plot, the nuclear chirality-parity (ChP) violation, the chiral rotation induced by the pairing correlations, as well as the chiral dynamics. The possibly emerging area, challenges that lie ahead, and opportunities for progress in the context of the nuclear chirality are discussed.

nucl-th↗
arXiv2023

Measurement of the Gamma-Ray Energy Spectrum beyond 100 TeV from the HESS J1843$-$033 Region

HESS J1843$-$033 is a very-high-energy gamma-ray source whose origin remains unidentified. This work presents, for the first time, the energy spectrum of gamma rays beyond $100\, {\rm TeV}$ from the HESS J1843$-$033 region using the data recorded by the Tibet air shower array and its underground muon detector array. A gamma-ray source with an extension of $0.34^{\circ} \pm 0.12^{\circ}$ is successfully detected above $25\, {\rm TeV}$ at $(α,\, δ) = (281.09^{\circ}\pm 0.10^{\circ},\, -3.76^{\circ}\pm 0.09^{\circ})$ near HESS J1843$-$033 with a statistical significance of $6.2\, σ$, and the source is named TASG J1844$-$038. The position of TASG J1844$-$038 is consistent with those of HESS J1843$-$033, eHWC J1842$-$035, and LHAASO J1843$-$0338. The measured gamma-ray energy spectrum in $25\, {\rm TeV} < E < 130\, {\rm TeV}$ is described with ${\rm d}N/{\rm d}E = (9.70\pm 1.89)\times 10^{-16} (E/40\, {\rm TeV})^{-3.26\pm 0.30}\, {\rm TeV}^{-1} {\rm cm}^{-2} {\rm s}^{-1}$, and the spectral fit to the combined spectra of HESS J1843$-$033, LHAASO J1843$-$0338, and TASG J1844$-$038 implies the existence of a cutoff at $49.5\pm 9.0\, {\rm TeV}$. Associations of TASG J1844-038 with SNR G28.6$-$0.1 and PSR J1844-0346 are also discussed in detail for the first time.

astro-ph.HE↗
arXiv2023

Observation of gamma rays up to 320 TeV from the middle-aged TeV pulsar wind nebula HESS J1849$-$000

Gamma rays from HESS J1849$-$000, a middle-aged TeV pulsar wind nebula (PWN), are observed by the Tibet air shower array and the muon detector array. The detection significance of gamma rays reaches $4.0\, σ$ and $4.4\, σ$ levels above 25 TeV and 100 TeV, respectively, in units of Gaussian standard deviation $σ$. The energy spectrum measured between $40\, {\rm TeV} < E < 320\, {\rm TeV}$ for the first time is described with a simple power-law function of ${\rm d}N/{\rm d}E = (2.86 \pm 1.44) \times 10^{-16}(E/40\, {\rm TeV})^{-2.24 \pm 0.41}\, {\rm TeV}^{-1}\, {\rm cm}^{-2}\, {\rm s}^{-1}$. The gamma-ray energy spectrum from the sub-TeV ($E < 1\, {\rm TeV}$) to sub-PeV ($100\, {\rm TeV} < E < 1\, {\rm PeV}$) ranges including the results of previous studies can be modeled with the leptonic scenario, inverse Compton scattering by high-energy electrons accelerated by the PWN of PSR J1849$-$0001. On the other hand, the gamma-ray energy spectrum can also be modeled with the hadronic scenario in which gamma rays are generated from the decay of neutral pions produced by collisions between accelerated cosmic-ray protons and the ambient molecular cloud found in the gamma-ray emitting region. The cutoff energy of cosmic-ray protons $E_{\rm p\, cut}$, cut is estimated at ${\rm log}_{10}(E_{\rm p,\, cut}/{\rm TeV}) = 3.73^{+2.98}_{-0.66}$, suggesting that protons are accelerated up to the PeV energy range. Our study thus proposes that HESS J1849$-$000 should be further investigated as a new candidate for a Galactic PeV cosmic-ray accelerator, PeVatron.

astro-ph.HE↗
arXiv2023

Nuclear chiral rotation induced by superfluidity

The microscopic understanding on the influence of the pairing correlations or the superfluidity on the nuclear chiral rotation has been a longstanding and challenging problem. Based on the three-dimensional cranking covariant density functional theory, a shell-model-like approach with exact particle number conservation is implemented to take into account the pairing correlations and applied for the chiral doublet bands in Nd135. The data available are well reproduced. It is found that the superfluidity can reduce the critical frequency and make the chiral rotation easier. The mechanism is that the particle/hole alignments along the short/long axis are reduced by the pairing correlations, resulting in the enhanced preference of the collective rotation along the intermediate axis, and inducing the early appearance of the chiral rotation.

nucl-th↗
arXiv2021

Gamma-ray Observation of the Cygnus Region in the 100 TeV Energy Region

We report observations of gamma-ray emissions with energies in the 100 TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1 with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources.

astro-ph.HE↗
arXiv2020

Pseudospin symmetry and octupole correlations for multiple chiral doublets in 131Ba

A reflection-asymmetric triaxial particle rotor model with three quasiparticles and a reflection-asymmetric triaxial rotor is developed, and applied to investigate the observed multiple chiral doublets (M\c{hi}D) candidates with octupole correlations in 131Ba, i.e., two pairs of positive-parity bands D3-D4 and D5-D6, as well as one pair of negative-parity bands D7-D8. The energy spectra, the energy staggering parameters, the B(M1)/B(E2) ratios, and the B(E1)/B(E2) ratios are reproduced well. The chiral geometries for these M\c{hi}D candidates are examined by the azimuthal plots, and the evolution of chiral geometry with spin is clearly demonstrated. The intrinsic structure for the positive-parity bands is analyzed and the possible pseudospin-chiral quartet bands are suggested.

nucl-th↗
arXiv2019

Travelling photons mediated interactions between a magnon mode and a cavity photon mode

We systematically study the indirect interaction between a magnon mode and a cavity photon mode mediated by travelling photons of a waveguide. From a general Hamiltonian, we derive the effective coupling strength between two separated modes, and obtain the theoretical expression of system's transmission. Accordingly, we design an experimental set-up consisting of a shield cavity photon mode, microstrip line and a magnon system to test our theoretical predictions. From measured transmission spectra, indirect interaction, as well as mode hybridization, between two modes can be observed. All experimental observations support our theoretical predictions. In this work, we clarify the mechanism of travelling photon mediated interactions between two separate modes. Even without spatial mode overlap, two separated modes can still couple with each other through their correlated dissipations into a mutual travelling photon bus. This conclusion may help us understand the recently discovered dissipative coupling effect in cavity magnonics systems. Additionally, the physics and technique developed in this work may benefit us in designing new hybrid systems based on the waveguide magnonics.

cond-mat.mes-hall↗
arXiv2008

Study on the spectrum of the injected relativistic protons

About 10TeV gamma-ray emission within 10 pc region from the Galactic Center had been reported by 4 independent groups. Considering that this TeV gamma-ray emission is produced via a hadronic model, and the relativistic protons came from the tidal disruption of stars by massive black holes, we investigate the spectral nature of the injected relativistic protons required by the hadronic model. The calculation was carried on the tidal disruption of the different types of stars and the different propagation mechanisms of protons in the interstellar medium. Compared with the observation data from HESS, we find for the best fitting that the power-law index of the spectrum of the injected protons is about -1.9, when a red giant star is tidally disrupted, and the effective confinement of protons diffusion mechanism is adopted.

astro-ph↗
arXiv2005

Modelling the evolution of dusty starburst galaxies in multi-band deep surveys

We model the constraints set on the evolution of dusty starburst galaxies by the current deep extragalactic surveys performed in the far-infrared with $\it Spitzer$, and at radio wavelengths with the VLA. Our models fit the number counts in all the available spectral bands well, and also provide a reasonably close match to the redshift distribution of the $\it Spitzer$ detections. We find: 1.) dusty starburst galaxies with infrared burst phases triggered by galactic interactions at redshift $z \sim 1-2$ are good candidates to fit the $\it Spitzer$ results at $24μm$, $70 μm$ and $160 μm$, assuming plausible strengths for the PAH features for the infrared luminous sources. An Arp220-like spectral energy distribution (SED) for Ultraluminous Infrared Galaxies (ULIGs) of $L_{\rm ir}>10^{12} L_{\odot}$ and one like that of M82 for Luminous Infrared Galaxies (LIGs) of $L_{\rm ir}\sim 10^{11-12} L_{\odot}$ give a successful fit to the $\it Spitzer$ $24μm$ and $\rm ISOCAM 15μm$ number counts at flux levels of $S_ν< 1 mJy$; 2.) the strong evolution of the number density of the ULIGs from redshift $z\sim 0$ to $\sim 1$ predicted by our models is consistent with the current deep $\rm 1.4 GHz$ radio surveys and accounts for the upturn in the $\rm 1.4 GHz$ differential counts at the sub-mJy flux level; and 3.) comparing with number counts at near infrared bands, as well as the background measurements using DIRBE and 2MASS, shows that only a fraction of the stellar mass in the Universe is included in our models of dusty starburst mergers at $z \sim 1 - 2$.

astro-ph↗
arXiv2002

Cosmic star formation history associated with QSO activity: an approach using the black hole to bulge mass correlation

The tight correlation between the masses of central black holes and their host spheroids in nearby galaxies and active galactic nuclei suggests that black hole growth is closely related to their spheroid formation. Based on our previous work regarding such a joint evolutionary scheme and the consequential black hole to bulge mass correlation, we use the X-ray luminosity function of AGN and the cosmological evolution rate which are from ROSAT X-ray surveys to estimate the cosmic star formation history associated with the black hole growth. By the Basic assumption that the major black hole growth occurs during the luminous AGN phase, the luminosity function of AGNs as a function of redshift traces not only the accretion history of the black holes but also the cosmic star formation history of the spheroids. Although the space density of the especially luminous QSOs is very low, we show that the total amount of star formation associated with the massive black hole growth is almost the same as that of Lyman Break Galaxies detected by the current optical deep surveys. We thus argue that the optical deep surveys may miss about half of the net star formation in our Universe, This is probably due to in part significant dust extinction as well as the small field of view of previous optical surveys which cannot sample such rare events with relatively short time scale. However, the far infrared emission from the dust heated by star fomation on-going during the black hole growth could sufficiently account for the observed SCUBA number counts, and would be the probable dominating energy source of the SUBA population.

astro-ph↗
arXiv2002

Contribution of starburst mergers at z~1 to the strong evolution of infrared and submillimeter deep surveys

Recent FIR/submm deep surveys revealed large number of ULIGs, which are proposed to lie at z>1, and in normally interacting systems with very dusty environments. We discussed in a previous paper that a population with a fast evolving infrared burst phase triggered by gas rich mergers at z~1 interpreted successfully the steep slope of IRAS 60um counts, leaving still a reasonable CIRB level at this wavelength. To extend the model to mid- and far-IR, we adopt a template SED as typical for nearby IR bright galaxies, such as Arp220. We construct the SED for the starburst mergers at z~1 by a simple dust extinction law and a thermal continuum assumption for the FIR emission. Since the radiation process at MIR for the merging systems is still uncertain, we assume it is similar to that of Arp220, but modify it by the observed flux correlation of ULIGs from IRAS, ISOCAM deep surveys. We show in this paper that the strong evolution of the ELAIS 90um, ISO 170um and the SCUBA 850um could be sufficiently accounted for by such an evolutionary scenario, especially for the hump of the ISOCAM 15um source count around 0.4mJy. From current best fit results, we find that the dust temperature of those merging system at z~1 would be higher than that of Arp220 for a reconciliation of the multi-wavelength deep surveys. The major difference of our current model prediction is that we see a fast convergence of the differential number counts at 60um below 50mJy, which is about a factor of two brighter than other model predictions. Future IR satellite like Astro-F,SIRTF would give strong constraints to the models.

astro-ph↗
arXiv2000

Black hole to bulge mass correlation in Active Galactic Nuclei: A test for the simple unified formation scheme

A mass correlation of central black holes and their spheroids ~0.002(within a factor of three) is suggested by Hubble Space Telescope (HST) and various ground-based CCD photometries of early type galaxies. The near-IR images of quasar hosts and the emission line measurements of Broad Line Region for bright QSOs present a similar correlation, which supports the speculation of an evolutionary linkage between the early active QSO phase and the central black holes in normal galaxies. On the other hand, recent reverberation mapping of a sample of Seyferts shows a broad distribution of black hole to bulge mass ratio with a mean of ~10^{-3.5}, about one magnitude lower than the value in early type galaxies and bright QSOs. Adopting a simple unified formation scheme for QSOs and Seyferts, we will discuss in this letter the dependence of the black hole to bulge mass ratio in Active Galactic Nuclei (AGNs) on the environmental parameters of the host galaxies. We show a broad distribution of the mass correlation could be due to different velocity dispersion of the accreting gas from different formation mechanism, and the mass ratio in normal galaxies and bright QSOs is probably a limit case of black hole evolution by merger enhanced accretion close to Eddington limit.

astro-ph↗
arXiv1999

An Exactly Solvable Model of Generalized Spin Ladder

A detailed study of an $S={1\over2}$ spin ladder model is given. The ladder consists of plaquettes formed by nearest neighbor rungs with all possible SU(2)-invariant interactions. For properly chosen coupling constants, the model is shown to be integrable in the sense that the quantum Yang-Baxter equation holds and one has an infinite number of conserved quantities. The R-matrix and L-operator associated with the model Hamiltonian are given in a limiting case. It is shown that after a simple transformation, the model can be solved via a Bethe ansatz. The phase diagram of the ground state is exactly derived using the Bethe ansatz equation.

cond-mat↗