Search results for "bound state"
showing 10 items of 235 documents
Ultrafast non-linear optical signal from a single quantum dot: exciton and biexciton effects
2002
We present results on both the intensity and phase-dynamics of the transient non-linear optical response of a single quantum dot (SQD). The time evolution of the Four Wave Mixing (FWM) signal on a subpicosecond time scale is dominated by biexciton effects. In particular, for the cross-polarized excitation case a biexciton bound state is found. In this latter case, mean-field results are shown to give a poor description of the non-linear optical signal at small times. By properly treating exciton-exciton effects in a SQD, coherent oscillations in the FWM signal are clearly demonstrated. These oscillations, with a period corresponding to the inverse of the biexciton binding energy, are correl…
Domain wall dynamics in an optical Kerr cavity
2004
An anisotropic (dichroic) optical cavity containing a self-focusing Kerr medium is shown to display a bifurcation between static --Ising-- and moving --Bloch-- domain walls, the so-called nonequilibrium Ising-Bloch transition (NIB). Bloch walls can show regular or irregular temporal behaviour, in particular, bursting and spiking. These phenomena are interpreted in terms of the spatio-temporal dynamics of the extended patterns connected by the wall, which display complex dynamical behaviour as well. Domain wall interaction, including the formation of bound states is also addressed.
Vortex mutual friction in rotating superfluid 3He
1996
The Manchester rotating cryostat has been used to measure the longitudinal and transverse coefficients of vortex mutual friction in the A and B phases of superfluid 3He. In the B phase the dominant contribution to the mutual friction is scattering of excitations off occupied bound states in the vortex core. The A phase results are explained quantitatively by assuming that doubly quantised continuous vortices are created with a dynamics determined by the equation of motion of the orbital vector I; the measurements enable us to put an upper limit on the orbital inertia of less than 0.01h{stroke} per Cooper pair. History-dependent textural effects which had to be overcome in order to make mean…
Bound-state dark matter and Dirac neutrino mass
2018
We propose a simple theory for the idea that cosmological dark matter (DM) may be present today mainly in the form of stable neutral hadronic thermal relics. In our model neutrino masses arise radiatively from the exchange of colored DM constituents, giving a common origin for both dark matter and neutrino mass. The exact conservation of $B-L$ symmetry ensures dark matter stability and the Dirac nature of neutrinos. The theory can be falsified by dark matter nuclear recoil direct detection experiments, leading also to possible signals at a next generation hadron collider.
CONSTRUCTION OF METASTABLE STATES IN QUANTUM ELECTRODYNAMICS
2004
In this paper, we construct metastable states of atoms interacting with the quantized radiation field. These states emerge from the excited bound states of the non-interacting system. We prove that these states obey an exponential time-decay law. In detail, we show that their decay is given by an exponential function in time, predicted by Fermi's Golden Rule, plus a small remainder term. The latter is proportional to the (4+β)th power of the coupling constant and decays algebraically in time. As a result, though it is small, it dominates the decay for large times. A central point of the paper is that our remainder term is significantly smaller than the one previously obtained in [1] and as…
A study of coupled-reaction channel effects in the36S +37Cl system, hybridization between single particle orbits
1996
Elastic and inelastic scattering as well as transfer transitions involving a valence proton in thesd- andfp- shell orbits are studied in the interaction of37Cl +36S at ECM=50 MeV. Experimental angular distributions of single particle states of37Cl (elastic and inelastic transfer) are presented with a CRC analysis. In the CRC calculations the effects of inelastic and transfer couplings are studied using known spectroscopic information. In the CRC analysis six single particle bound states and the collective 2+ excitation of36S are included in the coupling scheme. Higher order coupling effects are found to be important. A distinct effect, the mixing of single particle states (of different pari…
Simultaneous Measurement ofβ−Decay to Bound and Continuum Electron States
2005
We report the first measurement of a ratio {lambda}{sub {beta}{sub b}}/{lambda}{sub {beta}{sub c}} of bound-state ({lambda}{sub {beta}{sub b}}) and continuum-state ({lambda}{sub {beta}{sub c}}) {beta}{sup -}-decay rates for the case of bare {sup 207}Tl{sup 81+} ions. These ions were produced at the GSI fragment separator FRS by projectile fragmentation of a {sup 208}Pb beam. After in-flight separation with the B{rho}-{delta}E-B{rho} method, they were injected into the experimental storage-ring ESR at an energy of 400.5A MeV, stored, and electron cooled. The number of both the {sup 207}Tl{sup 81+} ions and their bound-state {beta}{sup -}-decay daughters, hydrogenlike {sup 207}Pb{sup 81+} ion…
Optical absorption band at5.8eVassociated with theEγ′centers in amorphous silicon dioxide: Optical absorption and EPR measurements
2008
Line shape modifications induced by thermal treatment in the optical absorption and electron paramagnetic resonance (EPR) signals associated with the ${E}_{\ensuremath{\gamma}}^{\ensuremath{'}}$ center are experimentally investigated in various types of $\ensuremath{\gamma}$-irradiated amorphous silicon dioxide $(a\text{\ensuremath{-}}\mathrm{Si}{\mathrm{O}}_{2})$. The $g$ values of the EPR main resonance line of the ${E}_{\ensuremath{\gamma}}^{\ensuremath{'}}$ center show a shift correlated with the peak energy variation of the absorption band at about $5.8\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ associated with this defect. These spectroscopic changes are proposed to originate from structu…
The screened cluster equation of state for hydrogen-helium mixtures: Atomic, molecular, and ionic contributions from first principles
2018
International audience
Binding of the BDD¯ and BDD systems
2017
We study theoretically the $BD\overline{D}$ and $BDD$ systems to see if they allow for possible bound or resonant states. The three-body interaction is evaluated implementing the fixed center approximation to the Faddeev equations which considers the interaction of a $D$ or $\overline{D}$ particle with the components of a $BD$ cluster, previously proved to form a bound state. We find an $I({J}^{P})=1/2({0}^{\ensuremath{-}})$ bound state for the $BD\overline{D}$ system at an energy around 8925--8985 MeV within uncertainties, which would correspond to a bottom hidden-charm meson. In contrast, for the $BDD$ system, which would be bottom double-charm and hence manifestly exotic, we have found h…