Community detection in multiplex networks using locally adaptive random walks

Multiplex networks, a special type of multilayer networks, are increasingly applied in many domains ranging from social media analytics to biology. A common task in these applications concerns the detection of community structures. Many existing algorithms for community detection in multiplexes attempt to detect communities which are shared by all layers. In this article we propose a community detection algorithm, LART (Locally Adaptive Random Transitions), for the detection of communities that are shared by either some or all the layers in the multiplex. The algorithm is based on a random walk on the multiplex, and the transition probabilities defining the random walk are allowed to depend on the local topological similarity between layers at any given node so as to facilitate the exploration of communities across layers. Based on this random walk, a node dissimilarity measure is derived and nodes are clustered based on this distance in a hierarchical fashion. We present experimental results using networks simulated under various scenarios to showcase the performance of LART in comparison to related community detection algorithms

Anatomy of molecular structures in 20^{20}Ne

We present a beyond mean-field study of clusters and molecular structures in low-spin states of $^{20}$Ne with a multireference relativistic energy density functional, where the dynamical correlation effects of symmetry restoration and quadrupole-octupole shapes fluctuation are taken into account with projections on parity, particle number and angular momentum in the framework of the generator coordinate method. Both the energy spectrum and the electric multipole transition strengths for low-lying parity-doublet bands are better reproduced after taking into account the dynamical octupole vibration effect. Consistent with the finding in previous studies, a rotation-induced dissolution of the $\alpha+^{16}$O molecular structure in $^{20}$Ne is predicted.Comment: 6 pages with 6 figures, version to be published in Phys. Lett.

A New Multiplicity Formula for the Weyl Modules of Type A

A monomial basis and a filtration of subalgebras for the universal enveloping algebra $U(g_l)$ of a complex simple Lie algebra $g_l$ of type $A_l$ is given in this note. In particular, a new multiplicity formula for the Weyl module $V(\lambda)$ of $U(g_l)$ is obtained in this note.Comment: 13 page

Direct mapping of the finite temperature phase diagram of strongly correlated quantum models

Optical lattice experiments, with the unique potential of tuning interactions and density, have emerged as emulators of nontrivial theoretical models that are directly relevant for strongly correlated materials. However, so far the finite temperature phase diagram has not been mapped out for any strongly correlated quantum model. We propose a remarkable method for obtaining such a phase diagram for the first time directly from experiments using only the density profile in the trap as the input. We illustrate the procedure explicitly for the Bose Hubbard model, a textbook example of a quantum phase transition from a superfluid to a Mott insulator. Using "exact" quantum Monte Carlo simulations in a trap with up to $10^6$ bosons, we show that kinks in the local compressibility, arising from critical fluctuations, demarcate the boundaries between superfluid and normal phases in the trap. The temperature of the bosons in the optical lattice is determined from the density profile at the edge. Our method can be applied to other phase transitions even when reliable numerical results are not available.Comment: 12 pages, 5 figure

Tunable Quantum Fluctuation-Controlled Coherent Spin Dynamics

Temporal evolution of a macroscopic condensate of ultra cold atoms is usually driven by mean field potentials, either due to scattering between atoms or due to coupling to external fields; and coherent quantum dynamics have been observed in various cold-atom experiments. In this article, we report results of studies of a class of quantum spin dynamics which are purely driven by zero point quantum fluctuations of spin collective coordinates. Unlike the usual mean-field coherent dynamics, quantum fluctuation-controlled spin dynamics or QFCSD studied here are very sensitive to variation of quantum fluctuations and can be tuned by four to five order of magnitude using optical lattices. They have unique dependence on optical lattice potential depths and quadratic Zeeman fields. QFCSD can be potentially used to calibrate quantum fluctuations and investigate correlated fluctuations and various universal scaling properties near quantum critical points.Comment: 14 pages, 12 figures included; including detailed discussions on thermal effects, trapping potentials and spin exchange losses. (To appear in PRA

Neutron halo in deformed nuclei from a relativistic Hartree-Bogoliubov model in a Woods-Saxon basis

Halo phenomenon in deformed nuclei is studied by using a fully self-consistent deformed relativistic Hartree-Bogoliubov model in a spherical Woods-Saxon basis with the proper asymptotic behavior at large distance from the nuclear center. Taking a deformed neutron-rich and weakly bound nucleus $^{44}$Mg as an example and by examining contributions of the halo, deformation effects, and large spatial extensions, we show a decoupling of the halo orbitals from the deformation of the core.Comment: 6 pages, 2 figures, to appear in the proceedings of the International Nuclear Physics Conference (INPC 2010), July 4-9 2010, Vancouve