1. INTRODUCTION There is a great demand for broadband antennas used for many applications such as the ultra-wideband (UWB) communications, the EMI measurements and the wideband radars. Considering the transmission and reception of pulse signals, not only broadband characteristics of input impedance and radiation pattern but also the distortionless condition are required. Among many types of bro...

Confocal Raman spectroscopy is used to study the phonon modes of mechanically exfoliated single-layer graphene sheets in ambient air. We observe that ambient gas induces obvious shifts in the G band frequency as well as the change in intensity ratio of 2D and G bands, I(2D)/I(G), owing to the Fermi energy change by ambient gas doping. The change in I(2D)/I(G) for the armchair edge is significan...

The (SrTiO3)m/(SrVO3)n d 0 − d multilayer system is studied with first principles methods through the observed insulator-to-metal transition with increasing thickness of the SrVO3 layer. When correlation effects with reasonable magnitude are included, crystal field splittings from the structural relaxations together with spin-orbit coupling (SOC) determines the behavior of the electronic and ma...

The thermal spectrum seen by accelerated observers in Minkowski space – known as the Unruh effect – is derived within the tunneling mechanism. Both Bose-Einstein and Fermi-Dirac spectrum is derived by considering tunneling of scalar and spin half particles respectively, across the accelerated Rindler horizon. Full solutions of Klein-Gordon and Dirac equations in the Rindler metric are employed ...

Motivated by recent experiments probing anomalous surface states of Dirac semimetals (DSMs) Na3Bi and Cd3As2, we raise the question posed in the title. We find that, in marked contrast to Weyl semimetals, the gapless surface states of DSMs are not topologically protected in general, except on time-reversal-invariant planes of surface Brillouin zone. We first demonstrate this finding in a minima...

A Monte Carlo method for calculation of the carrier mobility in degenerate bulk semiconductors at zero electric field is presented. The method is obtained as a limiting case of an existing small-signal approach replacing the distribution function by the Fermi-Dirac distribution which is valid at zero electric field. The general form of the Boltzmann equation which takes into account the Pauli e...

A generalized stochastic method for projecting out the ground state of the quantum many-body Schrödinger equation on curved manifolds is introduced. This random-walk method is of wide applicability to any second order differential equation (first order in time), in any spatial dimension. The technique reduces to determining the proper ‘‘quantum corrections’’ for the Euclidean short-time propaga...

We discuss the applications of Gauge Theory Gravity (GTG) within the language of geometric algebra to the Dirac equation in the de Sitter and Rindler metrics as well as to the Unruh effect. We rederive the Hawking temperature for each case. The derivation of both the correct Fermi-Dirac statistics as well as the Hawking temperature may suggest that the method of calculations we employ here geom...

We study two kinds of Dirac sea effects on the S0 pairing gap in nuclear matter based on the relativistic Hartree approximation to quantum hadrodynamics and the Gor’kov formalism. We show that the vacuum fluctuation effect on the nucleon effective mass is more important than the direct coupling between the Fermi sea and the Dirac sea due to the pairing interaction. The effects of the high-momen...

We study the evolution of sexual and asexual populations in general fitness landscapes. We find deep relations between the mathematics of biological evolution and the formalism of quantum mechanics. We give the general structure of the evolution of populations which is in general an off-equilibrium process that can be expressed by path integrals over phylogenies. These phylogenies are sums of l...