Search results for "GROUND STATE"
showing 10 items of 928 documents
Photoluminescence at the ground-state level anticrossing of the nitrogen-vacancy center in diamond: A comprehensive study
2021
Physical review / B 103(3), 035307 (2021). doi:10.1103/PhysRevB.103.035307
Exciton fine structure splitting of single InGaAs self-assembled quantum dots
2004
Abstract We show how the resonant absorption of the ground state neutral exciton confined in a single InGaAs self-assembled quantum dot can be directly observed in an optical transmission experiment. A spectrum of the differential transmitted intensity is obtained by sweeping the exciton energy into resonance with laser photons exploiting the voltage induced Stark-shift. We describe the details of this experimental technique and some example results which exploit the ∼1 μeV spectral resolution. In addition to the fine structure splitting of the neutral exciton and an upper bound on the homogeneous linewidth at 4.2 K , we also determine the transition electric dipole moment.
Observation of field phase dependent autoionization
1999
We report on the observation of a field phase dependent autoionization rate of calcium in the region of the doubly excited state. Excitation of the autoionizing state occurs from the atomic ground state through two phase related and hence interfering channels, namely a three photon channel and a single photon channel , being the third harmonic of . The autoionization rate exhibits a sinusoidal modulation as a function of the relative phase of the two excitation fields. Both ionizing fields are not focused in the interaction region, thus demonstrating the possibility of phase control in a large interaction volume and free of phase shift effects associated with focused geometries.
Cloud of virtual photons in the ground state of the hydrogen atom.
1985
A spinless, nonrelativistic hydrogen atom coupled to an electromagnetic field is considered. The interaction is taken in the minimal-coupling form, and the ground state of the coupled system is obtained by straightforward perturbation theory. The form of the cloud of virtual photons surrounding the atom is studied through the quantum-mechanical average on this state of an appropriately defined coarse-grained energy-density (CGED) operator W(r\ensuremath{\rightarrow}). The properties of W(r\ensuremath{\rightarrow}) are studied in order to show that this operator can give a reliable description of the shape of the virtual photon cloud. The quantum-mechanical average of W(r\ensuremath{\rightar…
The SVZ plasmon
1985
The sum rule technique of Shifman, Vainshtein and Zakharov is applied to a non-relativistic many-body system, the homogeneous, degenerate electron gas. The operator product expansion for the nonrelativistic correlation function is derived and shown to be equivalent in lowest order to a moment expansion. The nonperturbative terms in this expansion characterize the interacting ground state (“vacuum”) of the system. For the electron gas they can be related to the correlation energy which is very well known. Following as close as possible the SVZ procedure the mass of the plasmon (i.e. the dispersion coefficient of the collective plasma excitation) is calculated and compared with results from c…
A diffusion Monte Carlo study of small para-Hydrogen clusters
2007
Abstract An improved Monte Carlo diffusion model is used to calculate the ground state energies and chemical potentials of parahydrogen clusters of three to forty molecules, using two different p-H2-p-H2 interactions. The improvement is due to three-body correlations in the importance sampling, to the time step adjustment and to a better estimation of statistical errors. In contrast to path-integral Monte Carlo results, this method predicts no magic clusters other than that with thirteen molecules.
Quantum-state-selective decay spectroscopy of Ra213
2017
An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a $^{48}\mathrm{Ca}$ beam impinging on a thin $^{170}\mathrm{Er}$ target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the $5n$ evaporation channel $^{213}\mathrm{Ra}$ was mass-selected in SHIPTRAP, and the $^{213}\mathrm{Ra}$ ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 s…
Computing the nucleon Dirac radius directly at $Q^2=0$
2016
We describe a lattice approach for directly computing momentum derivatives of nucleon matrix elements using the Rome method, which we apply to obtain the isovector magnetic moment and Dirac radius. We present preliminary results calculated at the physical pion mass using a 2HEX-smeared Wilson-clover action. For removing the effects of excited-state contamination, the calculations were done at three source-sink separations and the summation method was used.
Recoil Decay Tagging Study Of Transitional Proton Emitters 145,146,147Tm
2005
International audience; Gamma rays from the transitional proton emitting nuclei 145,146,147Tm have been observed using the recoil-decay tagging technique. The ground state band of 147Tm was confirmed and extended and the unfavoured signature sequence was observed. A ground state rotational band with properties of a decoupled h11/2 band was observed in 145Tm. In addition coincidences between the proton fine structure line and the 2+-->0+ gamma-ray transition in 144Er were detected at the focal plane of the FMA. This is the first time that coincidences between proton radioactive decays and gamma rays have been seen. The particle decay of 146Tm has been measured with improved statistics and a …
Possible neutron and proton halo structure in the isobaric analog states of A=12 nuclei
2020
The differential cross sections of the $^{11}\mathrm{B}(^{3}\mathrm{He},d)^{12}\mathrm{C}$ reaction leading to formation of the ${0}^{+}$ ground state and the 15.11-MeV 1 ${}^{+}$, 16.57-MeV ${2}^{\ensuremath{-}}$, and 17.23-MeV ${1}^{\ensuremath{-}}$ excited states of $^{12}\mathrm{C}$ are measured at ${E}_{\text{lab}}=25$ MeV. The analysis of the data is carried out within the coupled-reaction-channels method for the direct proton transfer to the bound and unbound states. The rms radii of the last proton in all states studied are determined. A comparison of the rms radii of the $^{12}\mathrm{B}, ^{12}\mathrm{C}$, and $^{12}\mathrm{N}$ nuclei in the isobaric analog states (IASs) with isosp…