548 research outputs found
Exciton fine structure and spin decoherence in monolayers of transition metal dichalcogenides
We study the neutral exciton energy spectrum fine structure and its spin
dephasing in transition metal dichalcogenides such as MoS. The interaction
of the mechanical exciton with its macroscopic longitudinal electric field is
taken into account. The splitting between the longitudinal and transverse
excitons is calculated by means of the both electrodynamical approach and
perturbation theory. This long-range exciton
exchange interaction can induce valley polarization decay. The estimated
exciton spin dephasing time is in the picosecond range, in agreement with
available experimental data.Comment: 5 pages, 3 figure
Hadronic and radiative three-body decays of J/psi involving the scalars f0(1370), f0(1500) and f0(1710)
We study the role of the scalar resonances f0(1370), f0(1500) and f0(1710) in
the strong and radiative three-body decays of J/psi with J/psi to V + P P
(gamma gamma) and J/psi to gamma + P P (V V), where P (V) denotes a
pseudoscalar (vector) meson. We assume that the scalars result from a
glueball-quarkonium mixing scheme while the dynamics of the transition process
is described in an effective chiral Lagrangian approach. Present data on J/psi
to V + P P are well reproduced, predictions for the radiative processes serve
as further tests of this scenario.Comment: 15 page
Description of double beta decay within continuum-QRPA
A method to calculate the nuclear double beta decay (- and
-) amplitudes within the continuum random phase approximation
(cQRPA) is formulated. Calculations of the transition amplitudes
within the cQRPA are performed for ^{76}Ge, ^{100}Mo and ^{130}Te. A rather
simple nuclear Hamiltonian consisting of phenomenological mean field and
zero-range residual particle-hole and particle-particle interaction is used.
The calculated M^{2\nu} are almost not affected when the single-particle
continuum is taken into account. At the same time, a regular suppression of the
-amplitude is found that can be associated with additional
ground state correlations due to collective states in the continuum. It is
expected that future inclusion of the nucleon pairing in the single-particle
continuum will somewhat compensate the suppression.Comment: 20 pages, 1 figure, published versio
Exciton dynamics in WSe2 bilayers
We investigate exciton dynamics in 2H-WSe2 bilayers in time-resolved
photoluminescence (PL) spectroscopy. Fast PL emission times are recorded for
both the direct exciton with ~ 3 ps and the indirect optical
transition with ~ 25 ps. For temperatures between 4 to 150 K
remains constant. Following polarized laser excitation, we observe
for the direct exciton transition at the K point of the Brillouin zone
efficient optical orientation and alignment during the short emission time
. The evolution of the direct exciton polarization and intensity as a
function of excitation laser energy is monitored in PL excitation (PLE)
experiments.Comment: 4 pages, 3 figure
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