Electronic properties of graphene multilayers

We study the effects of disorder in the electronic properties of graphene multilayers, with special focus on the bilayer and the infinite stack. At low energies and long wavelengths, the electronic self-energies and density of states exhibit behavior with divergences near half-filling. As a consequence, the spectral functions and conductivities do not follow Landau's Fermi liquid theory. In particular, we show that the quasiparticle decay rate has a minimum as a function of energy, there is a universal minimum value for the in-plane conductivity of order e^2/h per plane and, unexpectedly, the c-axis conductivity is enhanced by disorder at low doping, leading to an enormous conductivity anisotropy at low temperatures.Comment: 4 pages, 4 figure. Reference to exciting new ARPES results on graphite added (we thank A. Lanzara for sharing the paper prior to its publication

Electromagnetic Corrections in Partially Quenched Chiral Perturbation Theory

We introduce photons in Partially Quenched Chiral Perturbation Theory and calculate the resulting electromagnetic loop-corrections at NLO for the charged meson masses and decay constants. We also present a numerical analysis to indicate the size of the different corrections. We show that several phenomenologically relevant quantities can be calculated consistently with photons which couple only to the valence quarks, allowing the use of gluon configurations produced without dynamical photons.Comment: 11 page

On the Entropy of a Family of Random Substitutions

The generalised random Fibonacci chain is a stochastic extension of the classical Fibonacci substitution and is defined as the rule mapping $0\mapsto 1$ and $1 \mapsto 1^i01^{m-i}$ with probability $p_i$, where $p_i\geq 0$ with $\sum_{i=0}^m p_i=1$, and where the random rule is applied each time it acts on a 1. We show that the topological entropy of this object is given by the growth rate of the set of inflated generalised random Fibonacci words.Comment: A more appropriate tile and minor misprints corrected, compared to the previous versio

Transmission through a biased graphene bilayer barrier

We study the electronic transmission through a graphene bilayer in the presence of an applied bias between layers. We consider different geometries involving interfaces between both a monolayer and a bilayer and between two bilayers. The applied bias opens a sizable gap in the spectrum inside the bilayer barrier region, thus leading to large changes in the transmission probability and electronic conductance that are controlled by the applied bias.Comment: 10 pages, 8 figures, extended versio

Persistent currents through a quantum impurity: Protection through integrability

We consider an integrable model of a one-dimensional mesoscopic ring with the conduction electrons coupled by a spin exchange to a magnetic impurity. A symmetry analysis based on a Bethe Ansatz solution of the model reveals that the current is insensitive to the presence of the impurity. We argue that this is true for any integrable impurity-electron interaction, independent of choice of physical parameters or couplings. We propose a simple physical picture of how the persistent current gets protected by integrability.Comment: 5 pages, minor update

Evolution from a nodeless gap to d(x2-y2) form in underdoped La(2-x)SrxCuO4

Using angle-resolved photoemission (ARPES), it is revealed that the low-energy electronic excitation spectra of highly underdoped superconducting and non-superconducting La(2-x)SrxCuO4 cuprates are gapped along the entire underlying Fermi surface at low temperatures. We show how the gap function evolves to a d(x2-y2) form as increasing temperature or doping, consistent with the vast majority of ARPES studies of cuprates. Our results provide essential information for uncovering the symmetry of the order parameter(s) in strongly underdoped cuprates, which is a prerequisite for understanding the pairing mechanism and how superconductivity emerges from a Mott insulator.Comment: 5 pages, 4 figure

A Theory of Rent Seeking with Informational Foundations

I develop a model of rent seeking with informational foundations and an arbitrary number of rent seekers, and I compare the results with Tullock’s (1980) classic model where the influence activities are “blackboxed.” Given the microfoundations, the welfare consequences of rent seeking can be studied. In particular, I show that competition among rent seekers can be socially beneficial, since the additional information that the decision maker gets access to makes the increase in rent-seeking expenditures worthwhile. However, the analysis also highlights a logic that, under natural parameter assumptions, makes the rent seekers spend more resources on rent seeking than is in society’s interest, which is consistent with the spirit of the rent-seeking literature

CP^n, or, entanglement illustrated

We show that many topological and geometrical properties of complex projective space can be understood just by looking at a suitably constructed picture. The idea is to view CP^n as a set of flat tori parametrized by the positive octant of a round sphere. We pay particular attention to submanifolds of constant entanglement in CP^3 and give a few new results concerning them.Comment: 28 pages, 9 figure

Penambahan Sari Jeruk Nipis terhadap Karakteristik Sirup Labu Siam

The purpose of this research was to obtain the ratio of chayote extracts and lime extractsin the manufactured of syrup. This research used Complete Randomized Design (CRD) with four treatments and four replication which followed by Duncan's New Multiple Range Test (DNMRT) at level 5%. The treatments in this research included LS0(ratio of chayote extracts and lime extracts 100 : 0), LS1 (ratio chayote extracts and lime extracts 95 : 05), LS2 (ratio chayote extracts and lime extracts 90 : 10), LS3 (chayote extracts and lime extracts 85 : 15). The results of analysis showed that the ratio of chayote extracts and lime extracts significantly effect on acidity (pH), viscosity, total dissolve, sucrose content and organoleptic value (colour, flavour, taste, consistency and overall acceptability). The bestsyrup was LS3 with acidity (pH) 4,45, viscosity 528,33cP, total dissolved 71,03 brix, sucrose content 65,44%. Overall preferred by the panelists with description the colour of rather murky, not falvorful chayote and falvorful lime, sweet taste little acidic and condensed

Determination of spin and parity of D(s)⁎ mesons

The spin and parity of the charmed mesons Ds⁎+, D⁎0 and D⁎+ are determined for the first time to be JP=1− with significances greater than 10σ over other hypotheses of 2+ and 3−, using an e+e− collision data sample with an integrated luminosity of 3.19 fb−1 collected by the BESIII detector at a center-of-mass energy of 4.178 GeV. Different spin-parity hypotheses are tested via a helicity amplitude analysis of the processes e+e−→Ds⁎+Ds−, D⁎0D0 and D⁎+D−, with Ds⁎+→Ds+γ, D⁎0→D0π0, and D⁎+→D+π0. The results confirm the quark model predictions.</p