• EPL (IF 1.958) Pub Date : 2020-09-21

We study the entropic considerations on the Universe system and the Universe-black hole system, filled by cosmological constant or exotic quintessence-like and phantom-like fields having negative pressure, using their relevant entropic bounds. It turns out that for both systems these considerations single out the cosmological constant, among the negative pressure candidate fields, as the viable cosmological

更新日期：2020-09-22
• EPL (IF 1.958) Pub Date : 2020-09-21
ZhaoHui Dong, Feng Xu and Wenyao Liang

Silicon-on-insulator (SOI) combined with topological photonics provides on-chip integrated photonic devices CMOS-compatibility and backscattering-suppression. Here we propose a tunable SOI-based valley Hall topological insulator with two nonequivalent air holes to break inversion symmetry. Due to free-carrier excitation, the real and imaginary parts of the refractive index are modified to cause a blue-shift

更新日期：2020-09-22
• EPL (IF 1.958) Pub Date : 2020-09-21
Ihor M. Kadenko, Barna Biró and András Fenyvesi

A new nuclear reaction channel on 197 Au with the neutron as a projectile and a bound dineutron ( 2 n) as an ejectile in the output channel is considered based on available experimental observations. The dineutron is assumed to be formed as a particle satellite, separated from the volume but not from the potential well of the 196 Au nucleus. The dineutron was identified by statistically significant

更新日期：2020-09-22
• EPL (IF 1.958) Pub Date : 2020-09-20
Young-Sea Huang

The classical Doppler-broadened absorption line profile, which is exactly derived by the classical Doppler effect and Maxwell speed distribution for the first time, is asymmetrically broadened with red-shift more than blue-shift, and its peak is red-shifted. Nonetheless, the half-width at half-maximum in the blue-shift wing is larger than that in the red-shift wing. The classical Doppler-broadened

更新日期：2020-09-21
• EPL (IF 1.958) Pub Date : 2020-09-20
Y. A. Ovchenkov, D. A. Chareev, D. E. Presnov, I. G. Puzanova, O. S. Volkova and A. N. Vasiliev

We have investigated the elastoresistance of two ##IMG## [http://ej.iop.org/images/0295-5075/131/5/57001/epl20272ieqn1.gif] {${\text{FeSe}}_{1-x}$} Te x ( ##IMG## [http://ej.iop.org/images/0295-5075/131/5/57001/epl20272ieqn2.gif] {$x\approx 0.4\text{--}0.5$} ) compounds that have a close chemical composition but differ significantly in electronic properties. The first compound has a negative temperature

更新日期：2020-09-21
• EPL (IF 1.958) Pub Date : 2020-09-20
U. Ali, M. Saleem, A. M. Qureshi, I. Riaz, M. Shah and W. Gao

The creation of unwound or unknotted loops of DNA is facilitated by topoisomerases, which alter the conformation of DNA by cleaving the phosphate backbone on one or both the strands. A major unexplored question has been the possibility of topoisomerases failing to unpack supercoiled DNA on any one of the several knots, thereby failing to initiate the unwinding process. Computing the unknotting number

更新日期：2020-09-21
• EPL (IF 1.958) Pub Date : 2020-09-20
Xiaogang Li and Jiancun Gao

Modular value of an observable of a pre- and postselected quantum system is a concept similar to weak value, but in contrast to describing only weak coupling, it can describe the coupling of any strength but only for qubit meters, so it may be used more widely in some scenarios. Besides, modular value has been proved to have advantages on measuring weak values of nonlocal joint observables and nonlocal

更新日期：2020-09-21
• EPL (IF 1.958) Pub Date : 2020-09-20
Niklas Wingren and Daniel Sjöberg

Scattering of electromagnetic waves against acoustic waves has been studied in acousto-optics and radio acoustic sounding of the atmosphere, among others. Strong interaction requires phase matching, which occurs at two angles between waves. These depend on the wavelength ratio. The scattered electromagnetic wave is frequency shifted by the acoustic frequency, either up or down depending on the angle

更新日期：2020-09-21
• EPL (IF 1.958) Pub Date : 2020-09-20
Hong Qian, Yu-Chen Cheng and Ying-Jen Yang

Stochastic kinematic description of a complex dynamics is shown to dictate an energetic and thermodynamic structure. An energy function ##IMG## [http://ej.iop.org/images/0295-5075/131/5/50002/epl20266ieqn1.gif] {$\varphi(\textbf{x})$} emerges as the limit of the generalized, nonequilibrium free energy of a Markovian dynamics with vanishing fluctuations. In terms of the ∇ φ and its orthogonal field

更新日期：2020-09-21
• EPL (IF 1.958) Pub Date : 2020-09-17
Haiying Li, Xiangbo Yang, Jiaye Wu and Xuhang Wu

We construct one-dimensional ##IMG## [http://ej.iop.org/images/0295-5075/131/5/54001/epl20249ieqn2.gif] {$\cal{PT}$} -symmetric ring optical waveguide networks with near-isometric and isometric arms and investigate their extraordinary optical properties. It is found that the features for the former and the latter are quite different, although extraordinary ultrastrong transmission and reflection exist

更新日期：2020-09-21
• EPL (IF 1.958) Pub Date : 2020-09-17
Chun-Xiao Nie

In recent years, the dynamics of the financial correlation matrix has been widely studied. This study applies the Frobenius distance-based kNN ( k nearest neighbour) network to analyse the time-varying characteristics of the correlation matrix, especially during the period of drastic change. We use the influence-strength ( IS ) index to detect when the correlation matrix structure changes dramatically

更新日期：2020-09-20
• EPL (IF 1.958) Pub Date : 2020-09-17
Kai-Ming Hu, Peng Bo, Xiu-Yuan Li, Yi-Hang Xin, Xin-Ru Bai, Lei Li and Wen-Ming Zhang

Intriguing mechanical properties of two-dimensional (2D) atomically thin materials make them well suit for a new class of resonant NEMS. Resonant 2D NEMS show high fundamental frequencies, outstanding tenability and broad dynamic range due to the ultrahigh strength, ultralow mass density and ultrahigh strain stretchability. Recent work toward exploring fabrication and transduction techniques, device

更新日期：2020-09-20
• EPL (IF 1.958) Pub Date : 2020-09-17
Marcell Blahota, István Blahota and Attila Szolnoki

Cyclic dominance offers not just a way to maintain biodiversity, but also serves as a sort of defensive alliance against an external invader. Interestingly, a new level of competition can be observed when two cyclic loops are present. Here the inner invasion speed plays a decisive role on the evolutionary outcome, because faster invasion rate provides an evolutionary advantage to an alliance. In this

更新日期：2020-09-20
• EPL (IF 1.958) Pub Date : 2020-09-16
S.-L. Su, F.-Q. Guo, J.-L. Wu, Z. Jin, X. Q. Shao and S. Zhang

Rydberg antiblockade (RAB) allows more than one Rydberg atom to be excited in the presence of Rydberg-Rydberg interaction (RRI) and has many potential applications in quantum optics, many-body physics and quantum information. In this paper, we would review the conditions and possible applications of different types of RAB regimes under weak, intermediate and strong RRIs, respectively. Both van der

更新日期：2020-09-18
• EPL (IF 1.958) Pub Date : 2020-09-07
Zi-Kang Zou, Lan Zhou, Wei Zhong and Yu-Bo Sheng

Quantum secure direct communication (QSDC) can realize the direct and secure transmission of information instead of sharing secure keys between two parties. Similar to quantum key distribution (QKD), in practical applications, QSDC may suffer from attacks from imperfect detector. Measurement-device–independent QSDC (MDI-QSDC) can remove all attacks at detector's side and close all loopholes in the

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-06
P. S. Ens and A. F. Santos

The f ( R ) gravity theory is considered. It is a gravitational theory that generalizes the Einstein-Hilbert action. In this context, a holographic dark energy model is studied. Tsallis non-extensive entropy is used to introduce the dark energy density based on the holographic principle. Then the Friedmann equation, deceleration parameter, and equation of state for this model are investigated.

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-06
Narges Vadood and Amir H. Fatollahi

The consequences of the gauge-coupling–dependent normalization factor of ##IMG## [http://ej.iop.org/images/0295-5075/131/4/41003/epl20258ieqn1.gif] {$1/g^{\alpha}$} in the transfer matrix of 2d U (1) lattice gauge theory are explored. It is seen by the ##IMG## [http://ej.iop.org/images/0295-5075/131/4/41003/epl20258ieqn2.gif] {$\alpha=1$} choice that the lowest energy develops a minimum at coupling

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-06
Vartika Singh, Suraj Prasad, Ankit Das, S. Narayanan and Deepak Kumar Mandal

When two identical drops evaporate simultaneously in close vicinity, the vapours of one drop affect the evaporation of the neighbouring one. The evaporation rate is found to decrease. The effect decreases when the in between spacing increases. The internal circulation, which is visualized, is observed to show the same behaviour. The circulation is slower for the nearer drops, but increases and becomes

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-06
Vincent P. Flynn, Emilio Cobanera and Lorenza Viola

Number-non-conserving terms in quadratic bosonic Hamiltonians can induce unwanted dynamical instabilities. By exploiting the pseudo-Hermitian structure built in to these Hamiltonians, we show that as long as dynamical stability holds, one may always construct a non-trivial dual (unitarily equivalent) number-conserving quadratic bosonic Hamiltonian. We exemplify this construction for a gapped harmonic

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-06
É. Brunet, A. D. Le, A. H. Mueller and S. Munier

In a branching process, the number of particles increasesexponentially with time, which makes numerical simulations for large timesdifficult. In many applications, however, only the region close to the extremalparticles is relevant (the “tip”). We present a simple algorithmwhich allows to simulate a branching random walk in one dimension, keepingonly the particles that arrive within some distance of

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-06
Hong-Jue Wang and Kai-Jia Sun

We focus on locating propagation source in complex networks. A novel and simple universal algorithm is proposed to accurately locate source of different heterogeneous propagation models by using only limited observed information without knowing anything about propagation models in advance. An observer nodes selecting strategy is proposed to improve the source locating accuracy of the proposed algorithm

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-06
Laura Lavacchi, Julian Kappler and Roland R. Netz

We study the non-Markovian Langevin dynamics of a massive particle in a one-dimensional double-well potential in the presence of multi-exponential memory by simulations. We consider memory functions as the sum of two or three exponentials with different friction amplitudes ##IMG## [http://ej.iop.org/images/0295-5075/131/4/40004/epl20260ieqn1.gif] {$\gamma_i$} and different memory times ##IMG## [http://ej

更新日期：2020-09-08
• EPL (IF 1.958) Pub Date : 2020-09-02
H. Takana, K. Yamamoto, T. Makino and M. Kanakubo

In this study, an innovative approach for the selective absorption of carbon dioxide (CO 2 ) by ionic liquid electrospray was proposed. First, the fluid dynamical characteristics of ionic liquid electrospray with 1-ethyl-3-methylimidazolium acetate in ambient air was clarified by high-speed imaging and aerosol analysis. This was followed by enhancement of CO 2 absorption by ionic liquid electrospray

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Yu Qian, Chi Zhang, Zegang Wei, Fei Liu, Chenggui Yao and Zhigang Zheng

The problem of oscillation mode recognition is one of the most important issues under investigation in the field of biological systems. In this paper, we have systematically investigated the optimal oscillation mode (OOM) identification in excitable small-world networks (ESWNs). It has been shown that rewiring probability, coupling strength and system size are the three determinants that can effectively

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Paulo R. F. Alves, Cleber N. Costa, Everton M. C. Abreu, Jorge Ananias Neto and Albert C. R. Mendes

In this paper we have analyzed the improved version of the Gauge Unfixing (GU) formalism of the massive Carroll-Field-Jackiw model, which breaks both the Lorentz and gauge invariances, to disclose hidden symmetries to obtain gauge invariance, the key stone of the Standard Model. In this process, as usual, we have converted this second-class system into a first-class one and we have obtained two gauge

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02

We explore the possibility that a super-light candidate for fuzzy (or wave) Dark Matter (fDM) may be a new composite boson state of fermions, rather than an axion-like Bose-Einstein condensate. We start from string-inspired massless Majorana fermions χ thought as super-modulini fields from string compactifications. We show that massless (or nearly massless) fermions can form a Bose-Einstein condensate

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Bastian Höckendorf, Andreas Alvermann and Holger Fehske

In two-dimensional anomalous Floquet insulators, non-Hermitian boundary state engineering can be used to completely separate chiral boundary states from bulk bands in the quasienergy spectrum. The topological properties of such spectrally separated boundary states are no longer restricted by the strict bulk-boundary correspondence of Hermitian systems. We show that this additional topological freedom

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Jie Lu, Linrong Zhang and Mengyun Wu

Game theories could help us to understand the origin of the emergence and persistence of cooperation among selfish individuals. Considering the intimate relationship among individuals, we study the prisoner's dilemma (PD) game in a two-layer network. Firstly, we calculate the closeness between any two players according to their connectivity. Further, we define and obtain one's comprehensive income

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Yue Chan

In this letter, we employ the Poisson-Nernst-Planck equation and the continuum molecular model to investigate the ionic layers formation in coaxial carbon nanotubes, which are crucial for understanding the ion transport in nanomaterials, as well as modern solar cells and batteries. Owing to the curvature of nanotubes and the strong ion-nanotubes interactions, our simulations show that stable ionic

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Fu-Quan Dou, Yuan-Jin Wang and Jian-An Sun

Quantum batteries are energy storage or extraction devices in a quantum system. Here, we present a closed-loop quantum battery by utilizing a circularly coupled three-state quantum system, and investigate its charging dynamics. The charging performance is greatly improved due to the existence of the third field in the system to form a closed-contour interaction. Through appropriately selecting the

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
V. I. Berezhiani and Z. Osmanov

Propagation and dynamics of electromagnetic vortex solitons have been studied in the electron positron ion plasmas of super-Eddington active galactic nuclei (AGN). Existence and stability of such structures is demonstrated for highly transparent AGN plasma media. Possible implications of dynamical features and corresponding observational signatures are discussed.

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Dharam Vir Ahluwalia

We have constructed a very different type of particle than any presently known. It is a boson and resides in the ##IMG## [http://ej.iop.org/images/0295-5075/131/4/41001/epl20257ieqn1.gif] {$(1/2,0)\oplus(0,1/2)$} representation space. The associated local field has mass dimension three-half. These new bosons can only be created or destroyed in pairs. When paired with a fermion the total zero point

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
A. Matzkin and D. Sokolovski

The place and role of an Observer in quantum mechanics has been a subject of an ongoing debate since the theory's inception. Wigner brought this question to the fore in a celebrated scenario in which a super-Observer observes a Friend making a measurement. Here we briefly review why this “Wigner Friend scenario” has been taken to require the introduction of the Observer's consciousness, or alternatively

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
R. Moazzemi

We explore the whole parameter space of the singlet fermionic cold-dark-matter model with respect to constraints on, first, the relic density and second, gamma-ray lines up to 10 TeV. We investigate 44000 random sample models which comprehensively scan the parameter space for dark-matter mass below 10 TeV, and compare our results with the latest experimental data from H.E.S.S., for the first time.

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Nasrin Banu, M. Aslam, Arpita Paul, Sanjib Banik, S. Das, S. Datta, A. Roy, I. Das, G. Sheet, U. V. Waghmare, S. Ramakrishnan and B. N. Dev

We report the observation of inhomogeneous superconductivity (ISC) in the recently discovered high-density nonmagnetic (NM) phase of Co in thin films below an onset temperature ( ##IMG## [http://ej.iop.org/images/0295-5075/131/4/47001/epl20262ieqn1.gif] {$T_{\mathrm{C}}$} ) of 5.4 K in the absence of external magnetic field, via four-probe measurements of resistivity. Further, the point-contact spectroscopy

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
Swarnapratim Bhattacharyya

A detailed study of event-by-event fluctuations of maximum particle density of the produced particles with respect to the width of the pseudo-rapidity interval in terms of the scaled variance ω has been carried out for 16 O-AgBr, 28 Si-AgBr and 32 S-AgBr interactions at 4.5 A GeV/ c . For all the interactions the values of scaled variance are found to be greater than one indicating the presence of

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-09-02
M. A. Sargsyan, D. V. Tereshonok, M. Kh. Gadzhiev and A. S. Tyuftyaev

In this work the destruction mechanism of a pure tungsten cathode during the initiation of direct current arc is studied. The experimental work shows that the cathode resides in liquid form during the initiation of the arc, and the process of its destruction happens by ejecting droplets from its surface with the following explosion. The average speed of the ejection and the temperature at the explosion

更新日期：2020-09-03
• EPL (IF 1.958) Pub Date : 2020-08-26
L. Morales-Molina, S. A. Reyes and E. Arévalo

We propose a method to probe ground states with distinct properties in binary mixtures trapped in small-ring lattices. The technique exploits the nonequilibrium particle current behavior generated by a nonadiabatic change of the interaction between the species of the binary mixture. The analysis of the current fluctuations in the Fourier space reveals a correspondence between the frequency peaks and

更新日期：2020-08-28
• EPL (IF 1.958) Pub Date : 2020-08-26
Ole L. Trinhammer

We examine interaction states between baryons in U (3) configurations. Such interaction states may represent the meson mass spectrum above the pion triplet. Our configuration space is the Lie group U (3) with a Hamiltonian structure for baryons as stationary states. Mesonic states come about via an interaction potential. The Hamiltonian can be diagonalized by a Rayleigh-Ritz method resulting in matrix

更新日期：2020-08-28
• EPL (IF 1.958) Pub Date : 2020-08-26
K. Y. Han, Z. H. Guo, H. X. Cao, Y. X. Du and C. Yang

Since masking of quantum information was introduced by Modi et al . in Modi K. et al ., Phys. Rev. Lett. , 120 (2018) 230501, many discussions on this topic have been published. In this paper, we explore the relationship between quantum multipartite maskers (QMMs) and quantum error-correcting codes (QECCs). We say that a subset Q of pure states of a system can be masked by an operator S into a multipartite

更新日期：2020-08-28
• EPL (IF 1.958) Pub Date : 2020-08-26
Y. Kawamura

The concept of Maxwell's displacement current is still not fully understood. In this paper, we measured the magnetic field between the plates of a charging capacitor using a magneto-optical method, which is generally explained to be produced by Maxwell's displacement current. We observed the asymmetric radial profile of the magnetic field between them, which could not be explained by using the displacement

更新日期：2020-08-28
• EPL (IF 1.958) Pub Date : 2020-08-26
Huayan Pei, Guanghui Yan and Huanmin Wang

To explore the incentive mechanisms of cooperation, inspired by preference for reputation in indirect reciprocity and the influence of behavioral observability on fitness, we present a new rewarding mechanism by incorporating these two impact factors into the evaluation of fitness in the spatial prisoner's dilemma game (PDG), under which a dynamically changing reward is established for cooperative

更新日期：2020-08-28
• EPL (IF 1.958) Pub Date : 2020-08-26
F. C. E. Lima and C. A. S. Almeida

We investigate the presence of vortex structures in a Maxwell model with a logarithmic generalization. This generalization becomes important because it generates stationary field solutions in models that describe the dynamics of a scalar field. In this work, we will choose to investigate the dynamics of the complex scalar field with the gauge field governed by the Maxwell term. For this, we will investigate

更新日期：2020-08-28
• EPL (IF 1.958) Pub Date : 2020-08-25
Qiu Wang, Jiao Wang, H. Z. Shen, S. C. Hou and X. X. Yi

In this work, taking the most general non-Hermitian Hamiltonian without parity-time ##IMG## [http://ej.iop.org/images/0295-5075/131/3/34001/epl20234ieqn1.gif] {$(\mathcal{PT})$} symmetry and with non-Hermitian off-diagonal elements into account, we study the exceptional points of the model system. We find that there exists an exceptional ellipse in theory, compared with the exceptional ring studied

更新日期：2020-08-28
• EPL (IF 1.958) Pub Date : 2020-08-25
D. Bazeia, L. Losano, M. A. Marques and R. Menezes

This work investigates twinlike scalar field models that support kinks with the same energy density and stability. We find the first-order equations compatible with the equations of motion. We use them to calculate the conditions under which they attain the twinlike character. The linear stability is also investigated, and there we show that the addition of extra requirements may lead to the same stability

更新日期：2020-08-27
• EPL (IF 1.958) Pub Date : 2020-08-25
Faizuddin Ahmed

In this paper, we study the Klein-Gordon equation subject to a magnetic quantum flux in the presence of a Cornell-type scalar and Coulomb-type vector potentials in a rotating cosmic string space-time. We solve the radial wave equation and evaluate the energy eigenvalues and eigenfunctions and analyze a relativistic analogue of Aharonov-Bohm effect for bound states.

更新日期：2020-08-27
• EPL (IF 1.958) Pub Date : 2020-08-25
Yan Qian, Erjun Kan, Kaiming Deng and Haiping Wu

Semiconductors simultaneously possessing high carrier mobility, moderate bandgap, and ambient environment stability are so important to modern industry, and Si-based semiconducting materials can match well with the previous silicon-based electronic components. Thus, searching for such Si-based semiconductors has been one hot project due to the lack of them nowadays. Here, with the help of density functional

更新日期：2020-08-27
• EPL (IF 1.958) Pub Date : 2020-08-24
J. Wang, A. Tiwari, I. M. Sivebaek and B. N. J. Persson

Using molecular dynamics we study the dependence of the friction force on the sliding speed when an elastic slab (block) is sliding on a rigid substrate with a ##IMG## [http://ej.iop.org/images/0295-5075/131/2/24006/epl20228ieqn1.gif] {$\text{sin} (q_0 x)$} surface height profile. The friction force is nearly velocity independent due to phonon emission at the closing and opening crack tips, where rapid

更新日期：2020-08-26
• EPL (IF 1.958) Pub Date : 2020-08-24
S. A. Owerre

We present a comprehensive study of strain-induced topological magnon phase transitions in insulating three-dimensional (3D) topological chiral antiferromagnets on the kagome-lattice. We show that by applying (100) uniaxial strain, 3D insulating antiferromagnetic Weyl magnons (WMs) manifest as an intermediate phase between a strain-induced 3D magnon Chern insulator (MCI) with integer Chern numbers

更新日期：2020-08-26
• EPL (IF 1.958) Pub Date : 2020-08-24
X. W. Meng, Y. Li, L. Shen and X. Q. Yang

Understanding and controlling water molecules confined in water channels has great applications. Many artificial water channels have been designed to mimic water permeation across water channels. One kind of artificial water channels, which contains two disjoint carbon nanotubes that are not physically connected has attracted much attention. Water transfers through the disjoint nanochannel by a water

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-24
V. K. Oikonomou and F. P. Fronimos

The striking GW170817 event indicated that the graviton is nearly massless, since the gamma rays emitted from the two neutron stars merging arrived almost simultaneously with the gravitational waves. Thus, the graviton must also be massless during the inflationary and post-inflationary era, since there is no obvious reason to believe otherwise. In this letter we shall investigate the theoretical implications

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-24
Yafei Zhang, Lin Wang, Jonathan J. H. Zhu and Xiaofan Wang

Quantifying the virality of cascades is an important question across disciplines such as the transmission of disease, the spread of information and the diffusion of innovations. An appropriate virality metric should be able to disambiguate between a shallow, broadcast-like diffusion process and a deep, multi-generational branching process. Although several valuable works have been dedicated to this

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-24
Kai Wang, Yong-Pan Gao, Ting-Tian Pang, Tie-Jun Wang and Chuan Wang

We study the photon blockade effect in a mechanical engineered quadratic optomechanical system. It is shown that the energy level structure of the system and the statistical properties of the photons can both be influenced through the modulation of the motion of the mechanical components. Also, the second-order correlation function is analyzed for which the photon blockade can be enhanced under the

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-23
Cui-Xian Guo, Xiao-Ran Wang and Su-Peng Kou

In this paper, based on a non-Hermitian toric-code model we found the fragileness of intrinsic topological orders under non-Hermitian perturbations. The effect of non-Hermitian avalanche for a designed toric-code model is uncovered: for the designed toric-code model with special external fields, a tiny non-Hermitian perturbation (local imaginary state-selective dissipation) leads to anomalous topological

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-23
Chuang Deng, Lin Wang, Zhihai Rong and Xiaofan Wang

Groups are the basic unit of organization in our society. It is important to investigate how groups compete and cooperation evolves in the population composed of groups. In this paper, based on the celebrated multi-player public goods game, we propose a general theoretical framework of the stochastic dynamic process to study how inequalities among groups affect the evolution of cooperation in a group

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-23
Finagnon Anselme Dossa

We study the solution of non-relativistic approximation of Dirac equation in the presence of non-Abelian external fields. The dynamics of the system is described by the Pauli Hamiltonian for a spin one-half particle carrying a non-Abelian charge. This non-Abelian charge, at the quantum level, is proportional to the generators of the U (2) gauge group and reveals the effect of a spin-orbit coupling

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-23
A. Mehmood, S. Qamar and S. Qamar

In this paper, we study the effects of the Kerr medium on the detection of a weak classical force acting on an optomechanical oscillator which is coupled purely dissipatively. We find that force sensing better than the standard quantum limit (SQL) of the mechanical oscillator can be achieved in the presence of Kerr medium. We show that increasing the strength of Kerr nonlinearity not only improves

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-23
Zengyao Lv, Zhencheng Li, Wangdong Xu and Yongmao Pei

Computational metamaterials, artificially structured materials, have enabled the realization of mathematical operations, such as spatial integration, differentiation, and convolution when waves propagate through them. However, experimental verifications and relevant applications of microwave computational metamaterials have rarely been achieved so far. In this paper, we present the theoretical and

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-23
Edson D. Leonel, Makoto Yoshida and Juliano Antonio de Oliveira

Some characteristics of scaling invariance are discussed for a transition from integrability to non-integrability in a class of dynamical systems described by a two-dimensional, nonlinear and area-preserving mapping. The dynamical variables are action I and angle θ and that the angle diverges in the limit of vanishingly action. The transition is controlled by a parameter ϵ closely related to the order

更新日期：2020-08-25
• EPL (IF 1.958) Pub Date : 2020-08-23
Chiao-Ying Chien and Jun Yamamoto

Improving the spatial resolution of the light-modulated scalar order parameter allows high-precision manipulation of functional molecules in the liquid crystals. This study shows that the poor resolution caused by the diffusion of azobenzene is overcome through the polymerization of an azobenzene monomer in the nematic phase. The photo-induced spatial variation of birefringence of non-polymerized and

更新日期：2020-08-25
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