Unconventional pairing in the iron arsenide superconductors

We use magnetic long range order as a tool to probe the Cooper pair wave function in the iron arsenide superconductors. We show theoretically that antiferromagnetism and superconductivity can coexist in these materials only if Cooper pairs form an unconventional, sign-changing state. The observation of coexistence in Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ then demonstrates unconventional pairing in this material. The detailed agreement between theory and neutron diffraction experiments, in particular for the unusual behavior of the magnetic order below $T_{c}$, demonstrates the robustness of our conclusions. Our findings strongly suggest that superconductivity is unconventional in all members of the iron arsenide family.Comment: 3 figures and 4 pages; final version as published

From cellular decision making to adaptive handoff in heterogeneous wireless networks

Handoff decision making is critical for mobile users to reap potential benefits from heterogeneous wireless networks. This letter proposes a biologically inspired handoff decisionmaking method by mimicking the dynamics which govern the adaptive behavior of an Escherichia coli cell in a time-varying environment.With the goal of guaranteeing the Quality of Service (QoS), we formulate a utility function that covers the demands of a user’s diverse applications and the time-varying network conditions. With this utility function, we map the dynamic heterogeneous environment to a cellular decision-making space, such that the user is induced by a cellular attractor selection mechanism to make distributed and robust handoff decisions. Furthermore, we also present a multi-attribute decision-making network selection algorithm for any user to determine an access network, which is integrated with the proposed bio-inspired decision-making mechanism. Simulation results are supplemented to show that the proposed method can achieve better QoS and fairness when it is compared with conventional methods

Antiparticle in Light of Einstein-Podolsky-Rosen Paradox and Klein Paradox

The original version of Einstein-Podolsky-Rosen (EPR) paradox and the Klein paradox of Klein-Gordon (KG) equation are discussed to show the necessity of existence of antiparticle with its wavefunction being fixed unambiguously. No concept of "hole" is needed.Comment: 4 pages, 0 figures. Accepted by Chinese Phys. Let

Operando and three-dimensional visualization of anion depletion and lithium growth by stimulated Raman scattering microscopy

Visualization of ion transport in electrolytes provides fundamental understandings of electrolyte dynamics and electrolyte-electrode interactions. However, this is challenging because existing techniques are hard to capture low ionic concentrations and fast electrolyte dynamics. Here we show that stimulated Raman scattering microscopy offers required resolutions to address a long-lasting question: how does the lithium-ion concentration correlate to uneven lithium deposition? In this study, anions are used to represent lithium ions since their concentrations should not deviate for more than 0.1 mM, even near nanoelectrodes. A three-stage lithium deposition process is uncovered, corresponding to no depletion, partial depletion, and full depletion of lithium ions. Further analysis reveals a feedback mechanism between the lithium dendrite growth and heterogeneity of local ionic concentration, which can be suppressed by artificial solid electrolyte interphase. This study shows that stimulated Raman scattering microscopy is a powerful tool for the materials and energy field