Ballistic transport properties across nonuniform strain barriers in graphene

We study the effect of uniaxial strain on the transmission and the conductivity across a strain-induced barrier in graphene. At variance with conventional studies, which consider sharp barriers, we consider a more realistic, smooth barrier, characterized by a nonuniform, continuous strain profile. Our results are instrumental towards a better understanding of the transport properties in corrugated graphene.Comment: High Press. Res., to appea

Dynamical polarization of graphene under strain

We study the dependence of the plasmon dispersion relation of graphene on applied uniaxial strain. Besides electron correlation at the RPA level, we also include local field effects specific for the honeycomb lattice. As a consequence of the two-band character of the electronic band structure, we find two distinct plasmon branches. We recover the square-root behavior of the low-energy branch, and find a nonmonotonic dependence of the strain-induced modification of its stiffness, as a function of the wavevector orientation with respect to applied strain.Comment: Phys. Rev. B, accepte

The mitochondrial unfolded protein response: Signaling from the powerhouse

Mitochondria are multifaceted and indispensable organelles required for cell performance. Accordingly, dysfunction to mitochondria can result in cellular decline and possibly the onset of disease. Cells use a variety of means to recover mitochondria and restore homeostasis, including the activation of retrograde pathways such as the mitochondrial unfolded protein response (UPRmt). In this Minireview, we will discuss how cells adapt to mitochondrial stress through UPRmt regulation. Furthermore, we will explore the current repertoire of biological functions that are associated with this essential stress-response pathway

Deep electronic states in ion-implanted Si

In this paper we present an overview of the deep states present after ion-implantation by various species into n-type silicon, measured by Deep Level Transient Spectroscopy (DLTS) and high resolution Laplace DLTS (LDLTS). Both point and small extended defects are found, prior to any anneal, which can therefore be the precursors to more detrimental defects such as end of range loops. We show that the ion mass is linked to the concentrations of defects that are observed, and the presence of small interstitial clusters directly after ion implantation is established by comparing their behaviour with that of electrically active stacking faults. Finally, future applications of the LDLTS technique to ion-implanted regions in Si-based devices are outlined.</p

Elevation of two subspecies of Dunnock Prunella modularis to species rank

The Western Palearctic endemic Dunnock Prunella modularis was recently revealed to comprise three distinct genetic lineages, each distributed in different Pleistocene refugia. Specifically, one is isolated in the Iberian refugium, another is confined to the Caucasus refugium, and the third is distributed in both the Italian and Balkan refugia, as well as across broader Europe. There is a probable absence of gene flow between the refugia. Analysis of plumage and song characteristics reveals robust differences between the Iberian subspecies P. m. mabbotti, Caucasian P. m. obscura and nominate P. m. modularis. Our assessments, in conjunction with genetic isolation, support species recognition under the Phylogenetic, Biological and Comprehensive Biological Species Concepts, via qualitative and quantitative criteria, and diagnosability. We thus propose the elevation of Iberian Dunnock P. mabbotti and Caucasian Dunnock P. obscura to species level

Recoherence in the entanglement dynamics and classical orbits in the N-atom Jaynes-Cummings model

The rise in linear entropy of a subsystem in the N-atom Jaynes-Cummings model is shown to be strongly influenced by the shape of the classical orbits of the underlying classical phase space: we find a one-to-one correspondence between maxima (minima) of the linear entropy and maxima (minima) of the expectation value of atomic excitation J_z. Since the expectation value of this operator can be viewed as related to the orbit radius in the classical phase space projection associated to the atomic degree of freedom, the proximity of the quantum wave packet to this atomic phase space borderline produces a maximum rate of entanglement. The consequence of this fact for initial conditions centered at periodic orbits in regular regions is a clear periodic recoherence. For chaotic situations the same phenomenon (proximity of the atomic phase space borderline) is in general responsible for oscillations in the entanglement properties.Comment: 15 pages (text), 6 figures; to be published in Physical Review

Quantum Return Probability for Substitution Potentials

We propose an effective exponent ruling the algebraic decay of the average quantum return probability for discrete Schrodinger operators. We compute it for some non-periodic substitution potentials with different degrees of randomness, and do not find a complete qualitative agreement with the spectral type of the substitution sequences themselves, i.e., more random the sequence smaller such exponent.Comment: Latex, 13 pages, 6 figures; to be published in Journal of Physics