Ultrafast all-optically controlled 2×2 crossbar switch

All-optical packet switching using all-optical routing control, where both ultrafast address recognition and routing of photonic packets were all optically performed on a header with 4 picosecond bit period, was demonstrated. Packets were self-routed through a node with no need for optoelectronic conversion. Terahertz optical asymmetric demultiplexer (TOAD) was used as an optically controlled 2×2 routing switch and as an all optical routing controller. TOAD read the individual address bits in the tightly compressed packet header and set the state of the routing switch. The bit-error rate at the switching element was measured to be less than 10-9

The Effect of Carbon Nanotube/Organic Semiconductor Interfacial Area on the Performance of Organic Transistors

We show that the performance of pentacene transistors can be significantly improved by maximizing the interfacial area at single walled carbon nanotube (SWCNT)/pentacene. The interfacial areas are varied by anchoring short SWCNTs of different densities (0-30/{\mu}m) to the Pd electrodes. The average mobility is increased three, six and nine times for low, medium and high SWCNT densities, respectively, compared to the devices with zero SWCNT. The current on-off ratio and on-current are increased up to 40 times and 20 times with increasing the SWCNT density. We explain the improved device performance using reduced barrier height of SWCNT/pentacene interface.Comment: 9 pages, 7 figures, 1 tabl

Spin Fluctuation Induced Dephasing in a Mesoscopic Ring

We investigate the persistent current in a hybrid Aharonov-Bohm ring - quantum dot system coupled to a reservoir which provides spin fluctuations. It is shown that the spin exchange interaction between the quantum dot and the reservoir induces dephasing in the absence of direct charge transfer. We demonstrate an anomalous nature of this spin-fluctuation induced dephasing which tends to enhance the persistent current. We explain our result in terms of the separation of the spin from the charge degree of freedom. The nature of the spin fluctuation induced dephasing is analyzed in detail.Comment: 4 pages, 4 figure

Theory of Fano-Kondo effect in quantum dot systems: temperature dependence of the Fano line shapes

The Fano-Kondo effect in zero-bias conductance is studied based on a theoretical model for the T-shaped quantum dot by the finite temperature density matrix renormalization group method. The modification of the two Fano line shapes at much higher temperatures than the Kondo temperature is also investigated by the effective Fano parameter estimated as a fitting parameter.Comment: 2 pages, 2 figures, the proceeding of SCES'0

Cascade of Quantum Phase Transitions in Tunnel-Coupled Edge States

We report on the cascade of quantum phase transitions exhibited by tunnel-coupled edge states across a quantum Hall line junction. We identify a series of quantum critical points between successive strong and weak tunneling regimes in the zero-bias conductance. Scaling analysis shows that the conductance near the critical magnetic fields $B_{c}$ is a function of a single scaling argument $|B-B_{c}|T^{-\kappa}$, where the exponent $\kappa = 0.42$. This puzzling resemblance to a quantum Hall-insulator transition points to importance of interedge correlation between the coupled edge states.Comment: 4 pages, 3 figure

Evaluating information systems for collaborative wellness

We are refining a system for studying Collaborative Wellness (CW) developed by us for use in evaluating knowledge creation and information systems. CW is founded on reaching agreement between stakeholders on ways to address issues arising in complex environments and create the necessary knowledge to address these issues. Such a model is needed in the increasingly complex and dynamic environment now found in business and society. Creating, managing and disseminating knowledge is crucial to enabling organisations to adapt to change in their dynamic environments. Despite this, we found gaps in organisational knowledge creation theory for supporting fine grained studies of knowledge creation. The Collaborative Wellness System (CWS) is intended to address this situation. CWS treats collaborations of knowledge creators as social information systems. CWS has an adaptable framework of measures that may be deployed to suit the circumstances of a collaboration. The measures of CW record assessments of the usefulness of created knowledge relative to agreed stakeholder expectations. The system allows collaborative experiences to be shared and compared. CWS informs the development, application, tracking and refinement of improvements to existing information systems. The CWS presented in this paper has been validated in four case studies involving business and government agencies

The influence of the knowledge-sharing process on technology business incubator performance in Saudi Arabia

In the competitive global market, technology business incubators are considered to be the backbone of the economic development of a country. Technology business incubators are involved in the creation of employment opportunities, boosting the local economy, and commercializing innovative technologies. This research-in-progress will propose a framework for technology business incubators to examine the impact of the knowledge-sharing practices of incubatees on technology business incubator performance both in general and in Saudi Arabia in particular. The key findings of this study will allow technology business incubators to better formulate the incubation process

Neutrino masses along with fermion mass hierarchy

Recently a new mechanism has been proposed to cure the problem of fermion mass hierarchy in the Standard Model (SM) model. In this scenario, all SM charged fermions other than top quark arise from higher dimensional operators involving the SM Higgs field. This model also predicted some interesting phenomenology of the Higgs boson. We generalize this model to accommodate neutrino masses (Dirac & Majorana) and also obtain the mixing pattern in the leptonic sector. To generate neutrino masses, we add extra three right handed neutrinos $(N_{iR})$ in this model.Comment: 20 pages, the content on results and phenomenology have been expanded, a new section on UV completion of the model has been added and also some new references, this version has been accepted by Physical Review