H. B. Ding

Bio: H. B. Ding is an academic researcher from Tsinghua University. The author has contributed to research in topics: Superconductivity & Physics. The author has an hindex of 8, co-authored 20 publications receiving 277 citations.

High-spin yrast and yrare structures in 112In

Abstract: The high-spin states of 112In have been investigated with in-beam \( \gamma\) -ray spectroscopic methods using the 110Pd (7Li, 5n)112In reaction at a beam energy of 50MeV. A level scheme with 3 band structures has been established. The backbending associated with the alignment of a pair of g7/2/d5/2 neutrons has been found in the negative-parity yrast band. The configuration for the positive-parity yrare band has been assigned to \( \pi\)g9/2 ⊗ \( u\)g7/2 for the lower-spin states, and \( \pi\)g9/2 ⊗ \( u\)h211/2(g7/2) for the higher-spin levels.

Identification of band structures and proposed one- and two-phonon {gamma}-vibrational bands in {sup 105}Mo

Abstract: High-spin band structures in neutron-rich {sup 105}Mo have been investigated by measuring prompt {gamma} rays emitted by the spontaneous fission fragments of {sup 252}Cf with the Gammasphere detector array. The yrast band has been confirmed and five new collective bands are observed. The three bands based on the 246.3-, 332.0-, and 310.0-keV levels are proposed as the single-neutron excitation bands built on the 3/2{sup +}[411], 1/2{sup +}[411], and 5/2{sup +}[413] Nilsson orbitals, respectively. The other two bands with band head levels at 870.5 and 1534.6 keV are candidates for one-phonon K=9/2 and two-phonon K=13/2 {gamma}-vibrational bands, respectively. Systematic comparison of these bands with bands in neighboring nuclei are discussed.

Search for octupole correlations in neutron-rich 148Cenucleus

Abstract: New transitions and levels in $^{148}\mathrm{Ce}$ have been observed in a $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ coincidence study from the spontaneous fission of $^{252}\mathrm{Cf}$ with Gammasphere detector array. The ground band has been extended up to ${I}^{\ensuremath{\pi}}={22}^{+}$, and side bands are extended with $\ensuremath{\Delta}I=2$ stretched transitions and $\ensuremath{\Delta}I=1$ crossing transitions. The observed level scheme is interpreted in terms of possible octupole correlations. Two sets of interwined positive- and negative- parity bands with the simplex quantum numbers $s=\ifmmode\pm\else\textpm\fi{}1$ are suggested. The results of $B(E1)/B(E2)$ branching ratios indicate that the octupole correlations in $^{148}\mathrm{Ce}$ are strong.

High-spin structure and multiphonon γ vibrations in very neutron-rich Ru 114

Abstract: High-spin levels of the neutron-rich $^{114}\mathrm{Ru}$ have been investigated by measuring the prompt $\ensuremath{\gamma}$ rays in the spontaneous fission of $^{252}\mathrm{Cf}$. The ground-state band and one-phonon $\ensuremath{\gamma}$-vibrational band have been extended up to 14${}^{+}$ and 9${}^{+}$, respectively. Two levels are proposed as the members of a two-phonon $\ensuremath{\gamma}$-vibrational band. A back bending (band crossing) has been observed in the ground-state band at $\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\approx}$ 0.40 MeV. Using the triaxial deformation parameters, the cranked shell model calculations indicate that this back bending in $^{114}\mathrm{Ru}$ should originate from the alignment of a pair of ${h}_{11/2}$ neutrons. Triaxial projected shell model calculations for the $\ensuremath{\gamma}$-vibrational band structures of $^{114}\mathrm{Ru}$ are in good agreement with the experimental data. However, when using the oblate deformation parameters, both of the above-calculated results are not in agreement with the experimental data.

Magnetic rotation in In-112

Abstract: The high spin states of $^{112}\mathrm{In}$ have been investigated with in-beam $\ensuremath{\gamma}$-ray spectroscopic methods using the $^{110}\mathrm{Pd}$$({}^{7}\mathrm{Li},5n)$$^{112}\mathrm{In}$ reaction at a beam energy of 50 MeV. A level scheme with three band structures has been established and their configurations are discussed. The positive-parity dipole band has been assigned as a magnetic rotation band. Particle-rotor model calculations have also been performed to interpret the rotational structures in $^{112}\mathrm{In}$.

Phase space representation of quantum dynamics

Abstract: We discuss a phase space representation of quantum dynamics of systems with many degrees of freedom. This representation is based on a perturbative expansion in quantum fluctuations around one of the classical limits. We explicitly analyze expansions around three such limits: (i) corpuscular or Newtonian limit in the coordinate-momentum representation, (ii) wave or Gross-Pitaevskii limit for interacting bosons in the coherent state representation, and (iii) Bloch limit for the spin systems. We discuss both the semiclassical (truncated Wigner) approximation and further quantum corrections appearing in the form of either stochastic quantum jumps along the classical trajectories or the nonlinear response to such jumps. We also discuss how quantum jumps naturally emerge in the analysis of non-equal time correlation functions. This representation of quantum dynamics is closely related to the phase space methods based on the Wigner-Weyl quantization and to the Keldysh technique. We show how such concepts as the Wigner function, Weyl symbol, Moyal product, Bopp operators, and others automatically emerge from the Feynmann's path integral representation of the evolution in the Heisenberg representation. We illustrate the applicability of this expansion with various examples mostly in the context of cold atom systems including sine-Gordon model, one- and two-dimensional Bose Hubbard model, Dicke model and others.

Effective action in a higher-spin background

Abstract: We consider a free massless scalar field coupled to an infinite tower of background higher-spin gauge fields via minimal coupling to the traceless conserved currents. The set of Abelian gauge transformations is deformed to the non-Abelian group of unitary operators acting on the scalar field. The gauge invariant effective action is computed perturbatively in the external fields. The structure of the various (divergent or finite) terms is determined. In particular, the quadratic part of the logarithmically divergent (or of the finite) term is expressed in terms of curvatures and related to conformal higher-spin gravity. The generalized higher-spin Weyl anomalies are also determined. The relation with the theory of interacting higher-spin gauge fields on anti de Sitter spacetime via the holographic correspondence is discussed.

Progress on tilted axis cranking covariant density functional theory for nuclear magnetic and antimagnetic rotation

Abstract: Magnetic rotation and antimagnetic rotation are exotic rotational phenomena observed in weakly deformed or near-spherical nuclei, which are respectively interpreted in terms of the shears mechanism and two shearslike mechanism. Since their observations, magnetic rotation and antimagnetic rotation phenomena have been mainly investigated in the framework of tilted axis cranking based on the pairing plus quadrupole model. For the last decades, the covariant density functional theory and its extension have been proved to be successful in describing series of nuclear ground-states and excited states properties, including the binding energies, radii, single-particle spectra, resonance states, halo phenomena, magnetic moments, magnetic rotation, low-lying excitations, shape phase transitions, collective rotation and vibrations, etc. This review will mainly focus on the tilted axis cranking covariant density functional theory and its application for the magnetic rotation and antimagnetic rotation phenomena.