119298312
A reconstruction of modified holographic Ricci dark energy in $f(R,T)$ gravity
In this paper, we consider a recently proposed model of Dark Energy (DE) know as Modified Holographic Ricci DE (MHRDE) (which is function of the Hubble parameter and its first derivative with respect to the cosmic time $t$) in the light of the $f(R,T)$ model of modified gravity, considering the particular model $f(R,T) = \mu R + \nu T$, with $\mu$ and $\nu$ constants. The equation of state (EoS) parameter $\omega_{\Lambda}$ approaches but never reaches the value -1, implying a quintessence-like behavior of the model. The deceleration parameter $q$ passes from decelerated to accelerated phase at a redshift of $z\approx 0.2$, showing also a small dependence from the values of the parameters considered. Thanks to the statefinder diagnostic analysis, we observed that the $\Lambda$CDM phase for the considered model is attainable. We observed that the fractional energy densities for DE and DM $\Omega_{\Lambda}$ and $\Omega_m$ have, respectively, an increasing and a decreasing pattern with the evolution of the universe, indicating an evolution from matter to DE dominated universe. Finally, studying the squared speed of the sound $v_s^2$ for our model, we found that is classically stable.
118578998
Interaction Between DBI-Essence and Other Dark Energies
The present work considers interaction between DBI-essence and other candidates of dark energies like modified Chaplygin gas, hessence, tachyonic field, and new agegraphic dark energy. The potentials of the fields have been reconstructed under interaction and their evolutions have been viewed against cosmic time t and scalar field φ. Equation of state parameters have also been obtained. The nature of potentials and the equation of state parameters of the dark energies have been found graphically in presence of interaction (both small and large interaction).
62820584
Correspondence between f(G) gravity and holographic dark energy via power-law solution
In this paper, we discuss cosmological application of holographic Dark Energy (HDE) in the framework of f(G) modified gravity. For this purpose, we construct f(G) model with the inclusion of HDE and a well-known power law form of the scale factor a(t). The reconstructed f(G) is found to satisfy a sufficient condition for a realistic modified gravity model. We find quintessence behavior of effective equation of state (EoS) parameter ωDE through energy conditions in this context. Moreover, we observe that the squared speed of sound $v_{s}^{2}$ remains negative, which indicates the instability of HDE f(G) model.
121538545
Interacting Ricci dark energy in scalar Gauss-Bonnet gravity
Abstract.This paper reports a study on the cosmological application of interacting Ricci Dark Energy (RDE) density in the scalar Gauss-Bonnet framework. The interacting holographic RDE model has been employed to obtain the equation of state (EoS) in a spatially flat universe. The main results of this paper are that the reconstructed potential of scalar Gauss-Bonnet gravity for the interacting RDE model decays with the evolution of the universe. However, it is an increasing function of the scalar field $ \phi$ . Both the strong and weak energy conditions are violated. A phantom-like behavior of the EoS parameter has been obtained. The effective EoS parameter $ \omega_{eff}$ stays below -1 but tends to -1 with the evolution of the universe. However, it cannot cross the phantom boundary. Finally, the interacting RDE model in Gauss-Bonnet gravity gives accelerated expansion of the universe.
119797547
New Agegraphic Dark Energy model in chameleon Brans-Dicke cosmology for different forms of the scale factor
In this work, we study the New Agegraphic Dark Energy (NADE) model (which contains the conformal time η as infrared cut-off) in the framework of Brans-Dicke cosmology with chameleon scalar field which is non-minimally coupled to the matter field. Considering interacting Dark Energy and Dark Matter (DM), we calculate some relevant cosmological parameters, i.e. the equation of state (EoS) parameter, the deceleration parameter q and the evolution of the energy density parameter $\varOmega_{D}'$ for different forms of scale factors, i.e. the power-law, the emergent, the intermediate and the logamediate ones, which leads to different expressions of η.
119137152
Power Law and Logarithmic Ricci Dark Energy Models in Hořava-Lifshitz Cosmology
In this work, we studied the Power Law and the Logarithmic Entropy Corrected versions of the Ricci Dark Energy (RDE) model in a spatially non-flat universe and in the framework of Hořava-Lifshitz cosmology. For the two cases containing non-interacting and interacting RDE and Dark Matter (DM), we obtained the exact differential equation that determines the evolutionary form of the RDE energy density. Moreover, we obtained the expressions of the deceleration parameter q and, using a parametrization of the equation of state (EoS) parameter ωD given by the relation ωD(z) = ω0+ω1z, we derived the expressions of both ω0 and ω1. We interestingly found that the expression of ω0 is the same for both non-interacting and interacting case. The expression of ω1 for the interacting case has strong dependence from the interacting parameter b2. The parameters derived in this work are done in small redshift approximation and for low redshift expansion of the EoS parameter.
119196987
Small quadrupole deformation for the dipole bands in 112 In
High spin states in 112 In were investigated using the 100 Mo( 16 O ,p 3n) reaction at 80 MeV. The excited level has been observed up to 5.6 MeV excitation energy and spin ∼20¯ h with the level scheme showing three dipole bands. Polarization and lifetime measurements were carried out for the dipole bands. Tilted axis cranking model calculations were performed for different quasiparticle configurations of this doubly odd nucleus. Comparison of the calculations of the model with the B(M1) transition strengths of the positive- and negative-parity bands firmly established their configurations.
11133970
Transverse envelope dynamics of a 28.5-GeV electron beam in a long plasma.
The transverse dynamics of a 28.5-GeV electron beam propagating in a 1.4 m long, (0-2)x10(14) cm(-3) plasma are studied experimentally in the underdense or blowout regime. The transverse component of the wake field excited by the short electron bunch focuses the bunch, which experiences multiple betatron oscillations as the plasma density is increased. The spot-size variations are observed using optical transition radiation and Cherenkov radiation. In this regime, the behavior of the spot size as a function of the plasma density is well described by a simple beam-envelope model. Dynamic changes of the beam envelope are observed by time resolving the Cherenkov light.
118269545
Studies of laser-driven 5 TeV e+e−colliders in strong quantum beamstrahlung regime
We explore the multidimensional space of beam parameters, looking for preferred regions of operation for a e+e− linear collider at 5 TeV center of mass energy. Due to several major constraints such a collider is pushed into certain regime of high beamstrahlung parameter, Υ, where beamstrahlung can be suppressed by quantum effect. The collider performance at high Υ regime is examined with IP simulations using the code CAIN. Given the required beam parameters we then discuss the feasibility of laser-driven accelerations. In particular, we will discuss the capabilities of laser wakefield acceleration and comment on the difficulties and uncertainties associated with the approach. It is hoped that such an exercise will offer valuable guidelines for and insights into the current development of advanced accelerator technologies oriented towards future collider applications.
25614674
On stochastic cooling of bunches in the colliding beam mode in high energy p-p storage rings
Possible cooling rates for stochastic cooling of intense bunches of protons and antiprotons in the colliding beam mode in the Fermilab Tevatron and the CERN SPS pp colliders are estimated, based solely on the bandwidth of the cooling system and the phase-space structure of the bunches and found to be a few tens of hours for high frequency large bandwidth feedback systems typically in the 8-16 GHz range and higher. The feasibility of even such slow cooling schemes, will depend on successful design of pick-ups, kickers and novel signal processing schemes in this high frequency regime, all of which demand detailed study.
117855388
Summary of Working Group 1 Beam Physics at High Energy Densities
The topics explored in the Working Group 1 at the Advanced Accelerator Concepts Workshop in Baltimore, Maryland (July 5–11, 1998) were concerned with Beam Physics at High Energy Densities. Particle beams of high phase space density and the associated environment of high energy density electromagnetic radiation—both appear at various stages of existing and envisioned colliders. Accordingly, in addition to general discussions on nonlinear Compton scattering, phase-space cooling, coherent electromagnetic emissions and plasma wakefield accelerations schemes, there were focussed discussions and presentations on two major collider frontiers of the day: (a) the severe electromagnetic and hadronic background environment at the IP of high energy multiple-TeV electron-positron-gamma colliders: and (b) muon beams for high energy muon colliders.