Search results for "Quasi particles"
showing 5 items of 5 documents
Two-phonon octupole excitation inGd146
2010
Based on experimental evidence from the $^{144}\mathrm{Sm}$($\ensuremath{\alpha},2n$) reaction, the $3484.7$-keV ${6}^{+}$ state in $^{146}\mathrm{Gd}$ is identified as the highest-spin member of the ${3}^{\ensuremath{-}}\ensuremath{\bigotimes}{3}^{\ensuremath{-}}$ two-phonon octupole quartet. A previously unknown $\ensuremath{\gamma}$ line of $1905.8$ keV and $E3$ character feeding the ${3}^{\ensuremath{-}}$ octupole state has been observed. These results represent the first observation of a ${6}^{+}\ensuremath{\rightarrow}{3}^{\ensuremath{-}}\ensuremath{\rightarrow}{0}^{+}$ cascade of two $E3$ transitions in an even-even nucleus and provide strong support for the interpretation of the ${6…
Interaction of two-level systems in amorphous materials with arbitrary phonon fields
2006
To describe the interaction of the two level systems (TLSs) of an amorphous solid with arbitrary strain fields, we introduce a generalization of the standard interaction Hamiltonian. In this new model, the interaction strength depends on the orientation of the TLS with respect to the strain field through a $6\times 6$ symmetric tensor of deformation potential parameters, $[R]$. Taking into account the isotropy of the amorphous solid, we deduce that $[R]$ has only two independent parameters. We show how these two parameters can be calculated from experimental data and we prove that for any amorphous bulk material the average coupling of TLSs with longitudinal phonons is always stronger than …
Electron capture decay of116Inand nuclear structure of doubleβdecays
1998
Quasiparticle-random-phase-approximation (QRPA) calculations of double $\ensuremath{\beta}$ decays have not been able to reproduce data in the $A=100$ system. We propose the $A=116$ system---because of its smaller deformation---as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of ${}^{116}\mathrm{In}$ to be $(2.27\ifmmode\pm\else\textpm\fi{}0.63)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}%$, from which we deduce $\mathrm{log}{ft=4.39}_{\ensuremath{-}0.15}^{+0.10}$. We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to…
Soliton rains in a fiber laser: An experimental study
2010
Rains of solitons constitute a class of nonlinear dynamics of dissipative soliton ensembles that we briefly reported in Opt. Express 17, 11776 (2009) from a fiber laser experiment. The existence of a relatively intense noisy background together with several tens of soliton pulses aggregated in a condensed soliton phase constitutes a necessary condition for their appearance. New soliton pulses form spontaneously from the background fluctuations and drift until they reach the condensed soliton phase. We here relate in detail the experimental conditions under which soliton rains manifest and their key features, describe related dynamics observed in their vicinity, and propose an explanation fo…
Quantization of the elastic modes in an isotropic plate
2006
We quantize the elastic modes in a plate. For this, we find a complete, orthogonal set of eigenfunctions of the elastic equations and we normalize them. These are the phonon modes in the plate and their specific forms and dispersion relations are manifested in low temperature experiments in ultra-thin membranes.