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We present a nonperturbative quasi-classical theory of graphene photoconductivity. We consider the influence of low-frequency (microwave, terahertz, mid-infrared) radiation on the static conductivity of a uniform graphene layer and…

Mesoscale and Nanoscale Physics · Physics 2021-06-09 S. A. Mikhailov

Interactions between light and conducting nanostructures can result in a variety of novel and fascinating phenomena. These properties may have wide applications, but their underlying mechanisms have not been completely understood. From…

Optics · Physics 2016-01-20 X. R. Huang , R. W. Peng , Mu Wang

Monolayer graphene absorbs 2.3 percent of the incident visible light. This 'small' absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of…

We show that every interval in the homomorphism order of finite undirected graphs is either universal or a gap. Together with density and universality this "fractal" property contributes to the spectacular properties of the homomorphism…

Combinatorics · Mathematics 2017-05-17 Jiří Fiala , Jan Hubička , Yangjing Long , Jaroslav Nešetřil

The duality and other symmetry properties of the effective conductivity sigma_e of the classical two-dimensional isotropic randomly inhomogeneous heterophase systems at arbitrary number of phases N are discussed. A new approach for a…

Disordered Systems and Neural Networks · Physics 2007-05-23 S. A. Bulgadaev

We investigate quantum transport in a normal/superconductor graphene heterostructure, including the possibility of an anisotropic pairing potential in the superconducting region. We find that under certain circumstances, the conductance…

Superconductivity · Physics 2009-11-13 J. Linder , A. Sudbø

The mechanisms of optical activity and quantum transport of twisted bilayer graphene are studied. The formation of unique electron states in the bilayer systems is studied using an effective continuum model. Such states are shown to support…

Mesoscale and Nanoscale Physics · Physics 2022-05-26 S. Ta Ho , V. Nam Do

Advances in infrared nanoscopy have enabled access to the finite momentum optical conductivity $\sigma(\vec{q},\omega)$. The finite momentum optical conductivity in graphene has a peak at the Dirac fermion quasiparticle energy…

Mesoscale and Nanoscale Physics · Physics 2012-10-17 Phillip E. C. Ashby , J. P. Carbotte

We obtain analytic expressions for the conductivity of pristine (pure) graphene in the framework of the Dirac model using the polarization tensor in (2+1)-dimensions defined along the real frequency axis. It is found that at both zero and…

Materials Science · Physics 2016-07-13 G. L. Klimchitskaya , V. M. Mostepanenko

We numerically and experimentally investigate graphene-based optical absorbers that exploit guided mode resonances (GMRs) achieving perfect absorption over a bandwidth of few nanometers (over the visible and near-infrared ranges) with a…

The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background…

Materials Science · Physics 2015-12-01 W. de Paula , a. Chaves , O. Oliveira , T. Frederico

We use Quantum Monte Carlo to evaluate the conductivity $\sigma$ of the 2--dimensional disordered boson Hubbard model at the superfluid-bose glass phase boundary. At the critical point for particle density $\rho=0.5$, we find…

Condensed Matter · Physics 2009-10-22 G. G. Batrouni , B. Larson , R. T. Scalettar , J. Tobochnik , J. Wang

We compute the universal conductivity of the (2+1)-dimensional XY universality class, which is realized for a superfluid-to-Mott insulator quantum phase transition at constant density. Based on large-scale Monte Carlo simulations of the…

Strongly Correlated Electrons · Physics 2015-09-23 Kun Chen , Longxiang Liu , Youjin Deng , Lode Pollet , Nikolay Prokof'ev

Starting from an arbitrary sequence of polygons whose total perimeter is $2n$, we can build an (oriented) surface by pairing their sides in a uniform fashion. Chmutov and Pittel (arXiv:1503.01816) have shown that, regardless of the…

Probability · Mathematics 2019-02-05 Thomas Budzinski , Nicolas Curien , Bram Petri

In most superconductors, optical excitations require impurity scattering or the presence of multiple bands. This is because in clean single-band superconductors, the combination of particle-hole and inversion symmetries prevents…

Superconductivity · Physics 2023-01-04 Michał Papaj , Joel E. Moore

We investigate the conductance of normal-conductor/graphene/normal-conductor (NGN) junctions for arbitrary on-site potentials in the normal and graphitic parts of the system. We find that a ballistic NGN junction can display insulating…

Mesoscale and Nanoscale Physics · Physics 2007-10-11 John P Robinson , Henning Schomerus

Monolayer graphene shows Seebeck coefficient several times and gas-flow-induced voltage twenty times higher than that of bulk graphite. Here we find that the Seebeck coefficient of multilayer graphene increases monotonically with increasing…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Xuemei Li , Jun Yin , Jianxin Zhou , Qin Wang , Wanlin Guo

A multigraph is a nonsimple graph which is permitted to have multiple edges, that is, edges that have the same end nodes. We introduce the concept of spanning simplicial complexes $\Delta_s(\mathcal{G})$ of multigraphs $\mathcal{G}$, which…

Algebraic Topology · Mathematics 2017-08-22 Imran Ahmed , Shahid Muhmood

The linear energy dispersion of graphene electrons leads to a strongly nonlinear electromagnetic response of this material. We develop a general quantum theory of the third-order nonlinear local dynamic conductivity of graphene…

Mesoscale and Nanoscale Physics · Physics 2016-02-04 S. A. Mikhailov

We show that the quantum chirality of charge carriers in graphene can be mimicked in optical structures. More precisely, we demonstrate that the particular form of the transmission coefficient at an interface in graphene between regions…

Mesoscale and Nanoscale Physics · Physics 2012-08-21 Daniela Dragoman , Adrian Radu , Sorina Iftimie