Morschet al. reply

Abstract

Morsch et al. Reply:The author of the preceding Comment 1 questions the extraction of narrow giant-dipoleresonance (GDR) widths, a main point of our previous Letter. 2 His conclusion was derived from a different analysis using full statistical-model calculations, suggesting that the data were better described by large GDR widths.Meanwhile, we have performed full statistical-model calculations for all excitation energies and obtain results very similar to those in the Comment (by using the same parameters). However, a comparison with the experimental data (not done in the Comment) leads to the following conclusions:(1) The experimental data cannot be described adequately with either large or small GDR widths (see Fig. 1).(2) Divided spectra as shown in Ref. 2, Fig. 2, reveal a splitting of the GDR structure which can be explained only by narrow resonances. This must be true for any analysis, including those using statistical-model calculations.To prove this, the experimental data are divided by statistical-model calculations (see Fig. 2). Using the calculations with small GDR widths yields the spectrum in Fig. 2(a). This shows why the standard calculation fails to describe the data [point (l)]: A low-energy peak is observed which is well described by a Lorentzian at Eo = 7.5 MeV with T=4.2 MeV. In similar plots this peak is observed at all excitation energies and was also conjectured in other measurements. 3 Using statistical-model calculations including only this new peak yields Fig. 2(b) which shows a giant-resonance structure with splitting similar to Fig. 2 in Ref. 2. The description of this spectrum requires small resonance widths. In the original analysis presented in Ref. 1 the GDR widths were extracted by a fit with an empirical function, Tb = 300 MeV 162 MeV i ri L j iJLii 29 FIG. 1. /-ray spectrum, bremsstrahlung subtracted, for excitation energy E x -162 MeV, from Ref. 2. The solid and dashed lines indicate statistical-model calculations using small and large giant-resonance widths, respectively. The parameters were those discussed in the preceding Comment except for the solid line for which the energy-weighted sum-rule strength is reduced to 53%. J , L (a) EY = 162MeV **J*uiaiu nihil. Ill (b) FIG. 2. (a) y-ray spectrum divided by a model calculation, equivalent to the solid line in Fig. 1. The solid line is a Lorentzian fit to the structure at 7 MeV. (b) Same data divided by a calculation including only the new low-energy component; this shows the GDR structure. The solid and dashed lines represent calculations with narrow and broad GDR widths, respectively.inspired by the statistical model. The broad low-energy component found here is reflected in the old analysis in the value of the low-energy slope parameter T s , which is systematically larger than the value obtained for the standard statistical-model results (see Fig. 1).In summary, the y-ray spectra in Ref. 2 are not described by standard statistical-model calculations (discussed in the Comment), revealing a new low-energy dipole structure [ Fig...

Excitation Spectrum in the Friedberg-Lee Model

“…This structure is consistent with the idea of Morsch et al 21) They consider the Roper resonance as the monopole excitation of the nucleon (the compression mode) using the analysis of the scalar-isoscalar excitation of the nucleon due to α-p scattering. Now we turn to the negative parity states.…”

Bose‐Einstein condensates as incubators of nonlinear and quantum optics

“…Collisional processes where the atoms are liberated in pairs from the condensate state represent an atom wave nonlinearity similar to the parametric generation of photons. Also the tunneling dynamics of a condensate within an optical lattice in presence of the atom nonlinearity, initially examined by Anderson and Kasevich [15] and later by Morsch et al [16], represents a nonlinear atom optic phenomenon. These last results are examined in the next Section.…”

“…where d is the distance between neighboring wells (lattice constant) and the depth U 0 of the potential depends on the laser intensity and the detuning of the lattice beams from the atomic resonance [11,16]. The lattice spacing d is varied by changing the angle θ between the laser beams forming the optical lattice, see .…”

Wave-packet dynamics of noninteracting ultracold bosons in an amplitude-modulated parabolic optical lattice

“…Pulse-like modulation of the OL amplitude allows us to selectively excite subsets of atoms in specific quasimomentum states. Bloch oscillations [9] and Landau-Zener (LZ hereafter) transitions [10] were observed in the past in ultracold atomic systems in OL in the presence of a constant force. These facts suggest that interferometric techniques for splitting and recombining the wave packets are feasible.…”