19,478 research outputs found
A new class of -d topological superconductor with topological classification
The classification of topological states of matter depends on spatial
dimension and symmetry class. For non-interacting topological insulators and
superconductors the topological classification is obtained systematically and
nontrivial topological insulators are classified by either integer or .
The classification of interacting topological states of matter is much more
complicated and only special cases are understood. In this paper we study a new
class of topological superconductors in dimensions which has
time-reversal symmetry and a spin conservation symmetry. We
demonstrate that the superconductors in this class is classified by
when electron interaction is considered, while the
classification is without interaction.Comment: 5 pages main text and 3 pages appendix. 1 figur
Electronic correlations and unusual superconducting response in the optical properties of the iron-chalcogenide FeTe0.55Se0.45
The in-plane complex optical properties of the iron-chalcogenide
superconductor FeTe0.55Se0.45 have been determined above and below the critical
temperature Tc = 14 K. At room temperature the conductivity is described by a
weakly-interacting Fermi liquid; however, below 100 K the scattering rate
develops a frequency dependence in the terahertz region, signaling the
increasingly correlated nature of this material. We estimate the dc
conductivity just above Tc to be sigma_dc ~ 3500 Ohm-1cm-1 and the superfluid
density rho_s0 ~ 9 x 10^6 cm-2, which places this material close to the scaling
line rho_s0/8 ~ 8.1 sigma_dc Tc for a BCS dirty-limit superconductor. Below Tc
the optical conductivity reveals two gap features at Delta_1,2 ~ 2.5 and ~ 5.1
meV.Comment: Minor revisions, 5 pages, 4 figure
An efficient auction mechanism for service chains in the NFV market
Network Function Virtualization (NFV) is emerging as a new paradigm for providing elastic network functions through flexible virtual network function (VNF) instances executed on virtualized computing platforms exemplified by cloud datacenters. In the new NFV market, well defined VNF instances each realize an atomic function that can be chained to meet user demands in practice. This work studies the dynamic market mechanism design for the transaction of VNF service chains in the NFV market, to help relinquish the full power of NFV. Combining the techniques of primal-dual approximation algorithm design with Myerson's characterization of truthful mechanisms, we design a VNF chain auction that runs efficiently in polynomial time, guarantees truthfulness, and achieves near-optimal social welfare in the NFV eco-system. Extensive simulation studies verify the efficacy of our auction mechanism. © 2016 IEEE.postprin
Glassy Dynamics in a Frustrated Spin System: Role of Defects
In an effort to understand the glass transition, the kinetics of a spin model
with frustration but no quenched randomness has been analyzed. The
phenomenology of the spin model is remarkably similiar to that of structural
glasses. Analysis of the model suggests that defects play a major role in
dictating the dynamics as the glass transition is approached.Comment: 9 pages, 5 figures, accepted in J. Phys.: Condensed Matter,
proceedings of the Trieste workshop on "Unifying Concepts in Glass Physics
Stable nanoemulsions for poorly soluble curcumin: From production to digestion response in vitro
Curcumin, a polyphenol, can induce anticancer activity depending on dose. However, oral curcumin administration is limited by its low bioavailability due to aqueous insolubility and instability against physiological conditions. This study aims at formulating nanoemulsions by phase inversion temperature to enhance curcumin loading, stability, antioxidant performance, bioaccessibility, and in vitro absorption. The selection mechanisms for oil phase (coconut oil), surfactant (polyoxyl 40 hydrogenated castor oil), co-surfactant (soy phospholipid), and aqueous phase (2 % wt citrate buffer at pH 4.5) are established. The nanoemulsions show tunable mean droplet size (26–129 nm), high curcumin loading (9.53 ± 0.49 mg/mL), polydispersity 0.05). The curcumin nanoemulsions show ∼ 11 %, 24 %, and 57 % higher retention and ∼ 10 %, 12 %, and 17 % higher antioxidant activity than raw curcumin after 3-hour simulated gastric, intestinal, and physiological incubations, respectively. During in vitro digestion and absorption, the encapsulated curcumin shows higher bioaccessibility and absorption than free curcumin (P < 0.05). The samples are stable during 4-week storage at 4˚C and room temperature without preservatives. These findings suggest the potential to develop a nanoencapsulation strategy, particularly for an oral delivery system of oil-soluble drugs
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