Signatures of tunable Majorana-fermion edge states

Chiral Majorana-fermion modes are shown to emerge as edge excitations in a superconductor--topological-insulator hybrid structure that is subject to a magnetic field. The velocity of this mode is tunable by changing the magnetic-field magnitude and/or the superconductor's chemical potential. We discuss how quantum-transport measurements can yield experimental signatures of these modes. A normal lead coupled to the Majorana-fermion edge state through electron tunneling induces resonant Andreev reflections from the lead to the grounded superconductor, resulting in a distinctive pattern of differential-conductance peaks.Comment: (13 pages, Accepted for publication in New Journal of Physics, an extension of and expansion on our previous work arXiv:1210.4057). arXiv admin note: text overlap with arXiv:1210.405

Neutral edge modes in a superconductor -- topological-insulator hybrid structure in a perpendicular magnetic field

We study the low-energy edge states of a superconductor -- 3D topological-insulator hybrid structure (NS junction) in the presence of a perpendicular magnetic field. The hybridization of electron-like and hole-like Landau levels due to Andreev reflection gives rise to chiral edge states within each Landau level. We show that by changing the chemical potential of the superconductor, this junction can be placed in a regime where the sign of the effective charge of the edge state within the zeroth Landau level changes more than once resulting in neutral edge modes with a finite value of the guiding-center coordinate. We find that the appearance of these neutral edge modes is related to the level repulsion between the zeroth and the first Landau levels in the spectra. We also find that these neutral edge modes come in pairs, one in the zeroth Landau level and its corresponding pair in the first.Comment: 5 page

DNA Computing and Implementations

DNA Computing aims to harness the molecules at the Nano level for computational purpose. DNA Computing features high data density and massive storage capability therefore, its approach can be used to solve various combinatorial Problems like solving Non Deterministic Problems (i.e. NP- Complete and NP-Hard). This Molecular Level Computational involve input and output both in the molecule form. Since DNA has already been explored as an exquisite material and is a fundamental block for manufacturing large scale Nano mechanical devices. DNA Computing is an approach towards the Biomolecular Computation where the aim is not only to process the information but also to transfer it to other molecular structures for utilization. DNA Computing is slower when an individual DNA Computes in compare to silica based chips. Its Efficiently and throughput increases as the number of DNA increase. DNA provides the possibility of massive parallelism. Starting with the Introduction about the DNA Structure, followed up by DNA Computers, this paper will discuss some recent advancements and challenges of DNA Computing. We will also discuss the possible future scope and implementation as well how the Artificial Intelligence approach can be used with DNA Based Computers to achieve a better and efficient Machine Learning

Kantowski-Sachsovi kozmološki modeli s vremenski-promjenljivim G i Λ

Kantowski-Sachs cosmological models with perfect fluid and time varying G and Λ are presented. Exact solutions of the field equations are obtained by using the scalar of expansion proportional to the shear scalar θ ∝ σ, which leads to a relation between the metric potentials A = Bn, where n is a constant. The corresponding physical interpretation of the cosmological solutions are also discussed.Predstavljamo Kantowski-Sachsove kozmološke modele s vremenski-promjenljivim G i Λ koji sadrže perfektnu tekućinu. Izvodimo egzaktna rješenja jednadžbi polja primjenom skalara razvoja koji je razmjeran posmičnom skalaru, θ ∝ σ, što vodi na relaciju među metričkim potencijalima A = Bn, gdje je n stalan. Raspravljamo i fizičko tumačenje kozmoloških rješenja

Kantowski-Sachsovi kozmološki modeli s vremenski-promjenljivim G i Λ

Kantowski-Sachs cosmological models with perfect fluid and time varying G and Λ are presented. Exact solutions of the field equations are obtained by using the scalar of expansion proportional to the shear scalar θ ∝ σ, which leads to a relation between the metric potentials A = Bn, where n is a constant. The corresponding physical interpretation of the cosmological solutions are also discussed.Predstavljamo Kantowski-Sachsove kozmološke modele s vremenski-promjenljivim G i Λ koji sadrže perfektnu tekućinu. Izvodimo egzaktna rješenja jednadžbi polja primjenom skalara razvoja koji je razmjeran posmičnom skalaru, θ ∝ σ, što vodi na relaciju među metričkim potencijalima A = Bn, gdje je n stalan. Raspravljamo i fizičko tumačenje kozmoloških rješenja

Mercury or Mercury Free Restorations in Oral Cavity

Amalgam is basically a concoction of metals that has been used as a potent filling material in dentistry for the last 150 years. Amalgam usually consists of silver, mercury, tin and copper. Dental amalgam is a material used to fill cavities of tooth. Over the years, amalgam has become a topic of concern because it contains mercury. Mercury is a naturally occurring metal in the environment. Mercury exists as a liquid in room temperature but when heated, it becomes a gas. Flexibility of amalgam as a filling material is due Mercury. An alloy powder, a compound that is soft in nature when mixed with mercury makes it enough to mix and condense into the tooth. It hardens quickly and offers strong resistance to the forces of biting and chewing. There are studies reported on the safety of amalgam fillings. In 2005, European Union launched a comprehensive mercury strategy to reduce use of mercury. In 2008, countries like Norway and Denmark restricted the use of dental amalgam containing mercury. In 2009, this research was evaluated by U.S. Food and Drug Administration (FDA) and found no rationale to limit the use of amalgam. There are certain restorative materials that are available commercially that are mercury free in nature like Gold, Porcelain, Gallium alloys, Composite resin restoratives etc. They offer many advantages over amalgams containing mercury like: seals the dentin from future decay, reinforces remaining tooth structure, provides smooth and bonded margins, conservative and it blends naturally

Bianchijev kozmološki model tipa-III sa strunama, volumnom viskoznošću i promjenljivim članom Λ

We study Einstein’s field equations in Bianchi type-III string cosmological models with bulk viscosity and variable cosmological term Λ. Exact solutions of the field equations are obtained by assuming the conditions: the bulk viscosity is proportional to the expansion scalar, ξ ∝ θ, expansion scalar is proportional to shear scalar, θ ∝ σ, and Λ is proportional to the Hubble parameter. The corresponding physical interpretations of the cosmological solutions are also discussed.Proučavamo Einsteinove jednadžbe polja u Bianchijevim kozmološkim modelima tipa III sa strunama, volumnom viskoznošću i promjenljivim kozmološkim članom Λ. Postigli smo egzaktna rješenja jednadžbi polja pretpostavivši uvjete: volumna viskoznost je razmjerna skalaru širenja, ξ ∝ θ, skalar širenja je razmjeran skalaru posmika, θ ∝ σ, i Λ je razmjerno Hubbleovom parametru. Raspravljaju se fizikalna tumačenja kozmoloških rješenja

Bianchijev kozmološki model tipa-III sa strunama, volumnom viskoznošću i promjenljivim članom Λ

We study Einstein’s field equations in Bianchi type-III string cosmological models with bulk viscosity and variable cosmological term Λ. Exact solutions of the field equations are obtained by assuming the conditions: the bulk viscosity is proportional to the expansion scalar, ξ ∝ θ, expansion scalar is proportional to shear scalar, θ ∝ σ, and Λ is proportional to the Hubble parameter. The corresponding physical interpretations of the cosmological solutions are also discussed.Proučavamo Einsteinove jednadžbe polja u Bianchijevim kozmološkim modelima tipa III sa strunama, volumnom viskoznošću i promjenljivim kozmološkim članom Λ. Postigli smo egzaktna rješenja jednadžbi polja pretpostavivši uvjete: volumna viskoznost je razmjerna skalaru širenja, ξ ∝ θ, skalar širenja je razmjeran skalaru posmika, θ ∝ σ, i Λ je razmjerno Hubbleovom parametru. Raspravljaju se fizikalna tumačenja kozmoloških rješenja

Dynamics of magnetic modulation of ferrofluid droplets for digital microfluidic applications

Active control of droplet generation in a microfluidic platform attracts interest for development of digital microfluidic devices ranging from biosensors to micro-reactors to point-of-care diagnostic devices. The present paper characterizes, through an unsteady three-dimensional Volume of Fluid (VOF) simulation, the active control of ferrofluid droplet generation in a microfluidic T-junction in presence of a non-uniform magnetic field created by an external magnetic dipole. Two distinctly different positions of the dipole were considered – one upstream of the junction and one downstream. While keeping the ferrofluid flow rate fixed, a parametric variation of the continuous phase capillary number, dipole strength, and dipole position was carried out. Differences in the flow behaviour in terms of dripping or jetting and the droplet characteristics in terms of droplet formation time period and droplet size were studied. The existence of a threshold dipole strength, below which the magnetic force was not able to influence the flow behaviour, was identified. It was also observed that, for dipoles placed upstream of the junction, droplet formation was suppressed at some higher dipole strengths, and this value was found to increase with increasing capillary number. Droplet time period was also found to increase with increasing dipole strength, along with droplet size, i.e. an increase in droplet volume