Pinned Bilayer Wigner Crystals with Pseudospin Magnetism

We study a model of \textit{pinned} bilayer Wigner crystals (WC) and focus on the effects of interlayer coherence (IC) on pinning. We consider both a pseudospin ferromagnetic WC (FMWC) with IC and a pseudospin antiferromagnetic WC (AFMWC) without IC. Our central finding is that a FMWC can be pinned more strongly due to the presence of IC. One specific mechanism is through the disorder induced interlayer tunneling, which effectively manifests as an extra pinning in a FMWC. We also construct a general "effective disorder" model and effective pinning Hamiltonian for the case of FMWC and AFMWC respectively. Under this framework, pinning in the presence of IC involves \textit{interlayer} spatial correlation of disorder in addition to intralayer correlation, leading to \textit{enhanced} pinning in the FMWC. The pinning mode frequency (\wpk) of a FMWC is found to decease with the effective layer separation, whereas for an AFMWC the opposite behavior is expected. An abrupt drop of \wpk is predicted at a transition from a FMWC to AFMWC. Possible effects of in-plane magnetic fields and finite temperatures are addressed. Finally we discuss some other possible ramifications of the FMWC as an electronic supersolid-like phase.Comment: Slightly revised. The final version is published on PR

Estimates for X(4350) Decays from the Effective Lagrangian Approach

The strong and electromagnetic decays of $X(4350)$ with quantum numbers $J^P =0^{++}$ and $2^{++}$ have been studied by using the effective Lagrangian approach. The coupling constant between $X(4350)$ and $D_s^{\ast}D_{s0}^{\ast}$ is determined with the help of the compositeness condition which means that $X(4350)$ is a bound state of $D_s^{\ast}D_{s0}^{\ast}$. Other coupling constants applied in the calculation are determined phenomenologically. Our numerical results show that, using the present data within the present model, the possibility that $X(4350)$ is a $D_s^{\ast}D_{s0}^{\ast}$ molecule can not be ruled out.Comment: 15 pages, 4 eps figure

On-Demand Spin-Orbit Interaction from Which-Layer Tunability in Bilayer Graphene

Spin-orbit interaction (SOI) that is gate-tunable over a broad range is essential to exploiting novel spin phenomena. Achieving this regime has remained elusive because of the weakness of the underlying relativistic coupling and lack of its tunability in solids. Here we outline a general strategy that enables exceptionally high tunability of SOI through creating a which-layer spin-orbit field inhomogeneity in graphene multilayers. An external transverse electric field is applied to shift carriers between the layers with strong and weak SOI. Because graphene layers are separated by sub-nm scales, exceptionally high tunability of SOI can be achieved through a minute carrier displacement. A detailed analysis of the experimentally relevant case of bilayer graphene on a semiconducting transition metal dichalchogenide substrate is presented. In this system, a complete tunability of SOI amounting to its ON/OFF switching can be achieved. New opportunities for spin control are exemplified with electrically driven spin resonance and topological phases with different quantized intrinsic valley Hall conductivities.Comment: 8 pages, 3 figure

Complex networks in climate dynamics - Comparing linear and nonlinear network construction methods

Complex network theory provides a powerful framework to statistically investigate the topology of local and non-local statistical interrelationships, i.e. teleconnections, in the climate system. Climate networks constructed from the same global climatological data set using the linear Pearson correlation coefficient or the nonlinear mutual information as a measure of dynamical similarity between regions, are compared systematically on local, mesoscopic and global topological scales. A high degree of similarity is observed on the local and mesoscopic topological scales for surface air temperature fields taken from AOGCM and reanalysis data sets. We find larger differences on the global scale, particularly in the betweenness centrality field. The global scale view on climate networks obtained using mutual information offers promising new perspectives for detecting network structures based on nonlinear physical processes in the climate system.Comment: 24 pages, 10 figure

Second-order superposition operations via Hong-Ou-Mandel interference

We propose an experimental scheme to implement a second-order nonlocal superposition operation and its variants by way of Hong-Ou-Mandel interference. The second-order coherent operations enable us to generate a NOON state with high particle number in a heralded fashion and also can be used to enhance the entanglement properties of continuous variable states. We discuss the feasibility of our proposed scheme considering realistic experimental conditions such as on-off photodetectors with nonideal efficiency and imperfect single-photon sources.Comment: published version, 6 pages, 6 figure