Search results for " gases"
showing 10 items of 941 documents
From Tree Unitarity to Top Quark Physics in 5D Higgsless Models
2005
In five dimensional models of Higgsless electroweak symmetry breaking, tree level unitarity in gauge boson scattering is restored by the exchange of gauge boson Kaluza-Klein modes instead of a Higgs boson. Unitarity of scattering amplitudes involving top quarks requires also the Kaluza-Klein modes of the third family quarks. It is shown that the relevant unitarity cancellations are consistent with gauge symmetry breaking by boundary conditions. These results are used to constrain the couplings of the top quark to Kaluza-Klein modes and the implications for collider phenomenology are discussed.
Finite-size scaling of the quark condensate in quenched lattice QCD
1999
We confront the finite volume and small quark mass behaviour of the scalar condensate, determined numerically in quenched lattice QCD using Neuberger fermions, with predictions of quenched chiral perturbation theory. We find that quenched chiral perturbation theory describes the numerical data well, allowing us to extract the infinite volume, chiral limit scalar condensate, up to a multiplicative renormalization constant.
One-Loop Self Energy and Renormalization of the Speed of Light for some Anisotropic Improved Quark Actions
2000
One-loop corrections to the fermion rest mass M_1, wave function renormalization Z_2 and speed of light renormalization C_0 are presented for lattice actions that combine improved glue with clover or D234 quark actions and keep the temporal and spatial lattice spacings, a_t and a_s, distinct. We explore a range of values for the anisotropy parameter \chi = a_s/a_t and treat both massive and massless fermions.
Time-dependent resonance interaction energy between two entangled atoms under nonequilibrium conditions
2018
We consider the time-dependent resonance interaction energy between two identical atoms, one in the ground state and the other in an excited state, and interacting with the vacuum electromagnetic field, during a nonequilibrium situation such as the dynamical atomic self-dressing process. We suppose the two atoms prepared in a correlated, symmetric or antisymmetric, state. Since the atoms start from a nonequilibrium conditions, their interaction energy is time dependent. We obtain, at second order in the atom-field coupling, an analytic expression for the time-dependent resonance interaction energy between the atoms. We show that this interaction vanishes when the two atoms are outside the l…
Geochemical characterisation of gases along the dead sea rift: Evidences of mantle-co2 degassing
2016
International audience; The Dead Sea Transform (DST) fault system, where a lateral displacement between the African and Arabian plates occurs, is characterised by anomalous heat flux in the Israeli area close to the border with Syria and Jordan. The concentration of He and CO2, and isotopic composition of He and total dissolved inorganic carbon were studied in cold and thermal waters collected along the DST, in order to investigate the source of volatiles and their relationship with the tectonic framework of the DST. The waters with higher temperature (up to 57.2 °C) are characterised by higher amounts of CO2 and helium (up to 55.72 and 1.91 * 10-2 cc l-1, respectively). Helium isotopic dat…
Tunable Polarons in Bose-Einstein Condensates
2017
A toolbox for the quantum simulation of polarons in ultracold atoms is presented. Motivated by the impressive experimental advances in the area of ultracold atomic mixtures, we theoretically study the problem of ultracold atomic impurities immersed in a Bose-Einstein condensate mixture (BEC). The coupling between impurity and BEC gives rise to the formation of polarons whose mutual interaction can be effectively tuned using an external laser driving a quasi-resonant Raman transition between the BEC components. Our scheme allows one to change the effective interactions between polarons in different sites from attractive to zero. This is achieved by simply changing the intensity and the frequ…
Isotope dependence of the Zeeman effect in lithium-like calcium
2016
The magnetic moment μ of a bound electron, generally expressed by the g-factor μ=−g μB s ħ−1 with μB the Bohr magneton and s the electron's spin, can be calculated by bound-state quantum electrodynamics (BS-QED) to very high precision. The recent ultra-precise experiment on hydrogen-like silicon determined this value to eleven significant digits, and thus allowed to rigorously probe the validity of BS-QED. Yet, the investigation of one of the most interesting contribution to the g-factor, the relativistic interaction between electron and nucleus, is limited by our knowledge of BS-QED effects. By comparing the g-factors of two isotopes, it is possible to cancel most of these contributions an…
Ionization and scintillation response of high-pressure xenon gas to alpha particles
2013
High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the ionization and scintillation detection properties of xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. We measure the ionization electron drift velocity and longitudinal diffusion, and compare our results to expectations based on available electron scattering cross sections on pure xenon. In addition, two types of measurements add…
The summit part of Mount Etna revealed by High Resolution DC Electrical Resistivity Tomography coupled with complementary geophysical and soil gas te…
2016
Between 25 June and 13 July 2015 a very deep ERT profile (Pole-Dipole configuration, 40m spacingbetween electrodes and a remote electrode located at ~10km from the acquisition points) has been performedin the framework of the “MED-SUV” Project. Self-potential, soil gas concentrations (CO2, 222Rn, 220Rn, He,H2 and CH4) and soil temperature measurements were coupled to the ERT profile with a spacing of 20m(except for Rn: 40m). The NE-SW profile crossed Etnas summit craters in the middle of the 5720m ERTtotal length. Six roll along protocols of . of the dispositive (600m out of 2520m tot) have been carried outand, for the first time, a high resolution DC ERT profile reached the noticeable inve…
Seed‐Layer‐Free Atomic Layer Deposition of Highly Uniform Al 2 O 3 Thin Films onto Monolayer Epitaxial Graphene on Silicon Carbide
2019
Atomic layer deposition (ALD) is the method of choice to obtain uniform insulating films on graphene for device applications. Owing to the lack of out-of-plane bonds in the sp(2) lattice of graphene, nucleation of ALD layers is typically promoted by functionalization treatments or predeposition of a seed layer, which, in turn, can adversely affect graphene electrical properties. Hence, ALD of dielectrics on graphene without prefunctionalization and seed layers would be highly desirable. In this work, uniform Al2O3 films are obtained by seed-layer-free thermal ALD at 250 degrees C on highly homogeneous monolayer (1L) epitaxial graphene (EG) (amp;gt;98% 1L coverage) grown on on-axis 4H-SiC(00…