Authors:F. E. A. Souza; G. Alencar, L. F. F. Freitas R. R. Landim First page: 50001 Abstract: In this paper the confinement of bosonic and spinning test particles in smooth Randall-Sundrum
models is studied. For this, we show the possibility of finding an effective potential that
describes the motion of the particle over the extra dimension. For the bosonic case, it is a known
fact that free test particles can be located neither on thin nor on thick branes. Recently, a
coupling to a scalar field has been used to localize a limited range of masses. Up to now, no
trapped test particles of any mass over the brane were found. In order to solve this, it is shown
that a coupling with the dilaton may trap particles of any mass. Next, the spinning particle is
analyzed. The spin variables, ##IMG##
[http://ej.iop.org/images/0295-5075/133/5/50001/epl20501ieqn1.gif] {$\psi^{P}$} , introduced an
interaction with the Riemann curvature tensor. It introduced a correction to the effective
potential. By analyzing it, it was found that the spinning particle may be loc... Citation: EPL (Europhysics Letters) PubDate: 2021-04-05T23:00:00Z DOI: 10.1209/0295-5075/133/50001 Issue No:Vol. 133, No. 5 (2021)

Authors:Faizuddin Ahmed First page: 50002 Abstract: We investigate quantum motion of spin-0 scalar particles in the presence of a uniform magnetic field
including quantum flux under the effects of Cornell- and Coulomb-type potentials in cosmic string
space-time. We evaluate the energy eigenvalues and eigenfunctions and analyze a relativistic
analogue of the Aharonov-Bohm effect. We show that the potentials allow the formation of bound
states solution, and the dependence of the magnetic field on quantum numbers of the system gives a
quantum effect. Citation: EPL (Europhysics Letters) PubDate: 2021-04-08T23:00:00Z DOI: 10.1209/0295-5075/133/50002 Issue No:Vol. 133, No. 5 (2021)

Authors:M. Bisi; M. Groppi, A. Macaluso G. Martalò First page: 54001 Abstract: A multi-temperature formal hydrodynamic limit of kinetic equations, based on Grad-type approximation
of the distribution functions, is employed for the analysis of the steady shock problem in a binary
mixture. The presence of a singular barrier and its effects on the occurrence of either smooth
profiles or of weak solutions with a discontinuity is investigated for varying Mach number. Some
numerical simulations of mixtures of two noble gases are presented and commented on, with reference
also to analogous phenomena in different model descriptions. Citation: EPL (Europhysics Letters) PubDate: 2021-04-05T23:00:00Z DOI: 10.1209/0295-5075/133/54001 Issue No:Vol. 133, No. 5 (2021)

Authors:Boultif Oussama; Ghezal Abdenasser Abdelaziz Sid First page: 55001 Abstract: Magneto-inertial fusion (MIF) is an approach for thermonuclear fusion. It consists in applying a
strong magnetic field to the inertial-fusion plasma, with the role of the magnetic field being to
limit the diffusion of the formed plasma during the impact of an intense laser pulse with a target
containing the thermonuclear fuel, as well as the confinement alpha particles produced by the fusion
reaction. This allows the reduction of energy loss and improves compression conditions. In this
paper we are interested in the study of the electron-ion inverse bremsstrahlung absorption (IBA) of
the laser energy in magnetized plasma in the MIF frame. In addition, we apply the derived formula to
calculate the absorption in magnetic fusion plasma heated by microwave. We use the
Fokker-Planck-Maxwell theory to calculate the IBA explicitly in magnetized plasma. Scaling laws for
IBA in MIF plasma and for magnetic confinement plasma are established. The numerical treatment of
the model equations ... Citation: EPL (Europhysics Letters) PubDate: 2021-04-07T23:00:00Z DOI: 10.1209/0295-5075/133/55001 Issue No:Vol. 133, No. 5 (2021)

Authors:Rui Tan; Qirui Yang, Ruiyuan Chen, Yu Qiao, Shouqiao Tan, Yanqiang Cao, Peng Wang, Tai-Chang Chiang Xiaoxiong Wang First page: 57001 Abstract: We use first-principles simulation and alchemical mixing approximation to reveal the unique double
band inversion and topological phase transition in Ge ##IMG##
[http://ej.iop.org/images/0295-5075/133/5/57001/epl20483ieqn1.gif] {$_{1-\mathit{x}}$} Sn ##IMG##
[http://ej.iop.org/images/0295-5075/133/5/57001/epl20483ieqn2.gif] {$_{\mathit{x}}$} alloys. Wave
function parity, spatial charge distribution and surface state spectrum analyses suggest that the
band inversion in Ge ##IMG## [http://ej.iop.org/images/0295-5075/133/5/57001/epl20483ieqn3.gif]
{$_{1-\mathit{x}}$} Sn ##IMG## [http://ej.iop.org/images/0295-5075/133/5/57001/epl20483ieqn4.gif]
{$_{\mathit{x}}$} is relayed by its first valence band. As the system evolves from Ge to ##IMG##
[http://ej.iop.org/images/0295-5075/133/5/57001/epl20483ieqn5.gif] {${\alpha}$} -Sn, its conduction
band moves down, and inverts with the f... Citation: EPL (Europhysics Letters) PubDate: 2021-04-05T23:00:00Z DOI: 10.1209/0295-5075/133/57001 Issue No:Vol. 133, No. 5 (2021)

Authors:Philipp Werner; Steven Johnston Martin Eckstein First page: 57005 Abstract: Resonant inelastic X-ray scattering (RIXS) detects various types of high- and low-energy elementary
excitations in correlated solids, and this tool will play an increasingly important role in
investigations of time-dependent phenomena in photo-excited systems. While theoretical frameworks
for the computation of equilibrium RIXS spectra are well established, the development of appropriate
methods for nonequilibrium simulations is an active research field. Here, we apply a recently
developed nonequilibrium dynamical mean field theory (DMFT) based approach to compute the RIXS
response of photo-excited two-orbital Mott insulators. The results demonstrate the feasibility of
multi-orbital nonequilibrium RIXS calculations and the sensitivity of the quasi-elastic
fluorescence-like features and ##IMG##
[http://ej.iop.org/images/0295-5075/133/5/57005/epl20500ieqn1.gif] {$d{\text{-}}d$} excitation peaks
on the nonequilibrium population of the Hubbard bands. Citation: EPL (Europhysics Letters) PubDate: 2021-04-11T23:00:00Z DOI: 10.1209/0295-5075/133/57005 Issue No:Vol. 133, No. 5 (2021)

Authors:Ben-Hur Francisco Cardoso; Sebastián Gonçalves First page: 58001 Abstract: Due to the COVID-19 pandemic, Susceptible-Infective-Recovered (SIR) models and their variants are in
high demand for predicting the number of cases in urban areas. Aiming to correctly use the
experience of the epidemic evolution from one local to another, we present an analysis of the
transmission rate of COVID-19 as a function of population size at the metropolitan area level for
the United States. Contrary to the usual hypothesis in epidemics modeling, we observe that the
disease transmissibility scales with the logarithm of the local's population size. The analysis,
made possible by a large amount of data available on simultaneous epidemics of the same type, is
universal for any human-to-human transmission disease. We present a contact rate scaling theory that
explains the results. Citation: EPL (Europhysics Letters) PubDate: 2021-04-05T23:00:00Z DOI: 10.1209/0295-5075/133/58001 Issue No:Vol. 133, No. 5 (2021)

Authors:Chuang Wu; Wei Zheng, Nan Si, Chunmei Li, Yanli Zhang Wei Jiang First page: 58002 Abstract: In this study, we have systematically investigated the electronic structures, magnetic and elastic
properties of the full-Heusler compounds Cr 2- x Fe x MnSi ( ##IMG##
[http://ej.iop.org/images/0295-5075/133/5/58002/epl20506ieqn1.gif] {$x = 0$} , 1, and 2) by density
functional theory calculations using the CASTEP with the generalized gradient approximation for the
exchange-correlation functional. Our calculation results show that the Cr 2 MnSi, CrFeMnSi and Fe 2
MnSi alloys exhibit excellent half-metallic materials, and half-metallic band gap will be larger as
the number of Fe atoms increases. The magnetism originates from the spin contribution of Cr-, Fe-
and Mn- d orbital electrons and the strong hybridization between them. The total magnetic moment of
Cr 2- x Fe x MnSi ( ##IMG## [http://ej.iop.org/images/0295-5075/133/5/58002/epl20506...] {$x = 0$} Citation: EPL (Europhysics Letters) PubDate: 2021-04-07T23:00:00Z DOI: 10.1209/0295-5075/133/58002 Issue No:Vol. 133, No. 5 (2021)

Authors:Eric Lauga; Thanh Nghi Dang Takuji Ishikawa First page: 44002 Abstract: Microorganisms self-propelling in a fluid create flow fields that impact the dynamics of other
swimmers. Some organisms can be biased and have a preferred swimming direction, e.g. , those
displaying gyrotaxis, chemotaxis or phototaxis, and as a result often focus along thin lines. Here
we use numerical computations and far-field theoretical calculations to show that the position of a
collection of biased swimmers moving along a line is unstable to a zigzag mode when the swimmers act
on the fluid as pusher dipoles. This instability takes the form of periodic transverse oscillations
in the position of the swimmers. We predict theoretically that the most unstable wavelength is equal
to twice the inter-swimmer distance and that the growth rate of the instability increases linearly
with the magnitude of the stresslet, both of which are in quantitative agreement with our numerical
simulations. Citation: EPL (Europhysics Letters) PubDate: 2021-04-08T23:00:00Z DOI: 10.1209/0295-5075/133/44002 Issue No:Vol. 133, No. 4 (2021)

Authors:Ole L. Trinhammer First page: 31001 Abstract: We create quarks from baryons in stead of constituting baryons from quarks. The quantum fields of
QCD are generated via the exterior derivative (momentum form) of baryon wave functions on an
intrinsic configuration space, the Lie group U (3). Local gauge transformations correspond to
coordinate translations in the intrinsic space. A proton spin structure function and a proton
magnetic moment are derived. We show how the spectrum of unflavoured baryons, the N and Delta
resonances, can be understood from a mass Hamiltonian on the intrinsic space and note how our model
resolves the problem of colour confinement. We calculate an approximate value for the relative
neutron-to-proton mass shift and give an exact value for the neutron mass. We predict neutral charge
singlets that may be interpreted as neutral pentaquarks at LHCb. Citation: EPL (Europhysics Letters) PubDate: 2021-04-06T23:00:00Z DOI: 10.1209/0295-5075/133/31001 Issue No:Vol. 133, No. 3 (2021)