Search results for "collective excitation"
showing 4 items of 4 documents
Plasmon Excitations in Mixed Metallic Nanoarrays
2019
Features of the surface plasmon from macroscopic materials emerge in molecular systems, but differentiating collective excitations from single-particle excitations in molecular systems remains elusive. The rich interactions between single-particle electron-hole and collective electron excitations produce phenomena related to the chemical physics aspects within the atomic array. We study the plasmonic properties of atomic arrays of noble (Au, Ag, and Cu) and transition-metal (Pd, Pt) homonuclear chains using time-dependent density functional theory and their Kohn-Sham transition contributions. The response to the electromagnetic radiation is related to both the geometry-dependent confinement…
Disentangling decaying isomers and searching for signatures of collective excitations in β decay
2019
6 pags., 3 figs., 1 tab. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK
Collective 2$^{+1}$ excitations in$^{206}$Po and$^{208,210}$Rn
2016
In the present study, $B(E2; 2^{+}_{1}\rightarrow 0^{+}_{1})$ values have been measured in the 208,210Rn and 206Po nuclei through Coulomb excitation of re-accelerated radioactive beams in inverse kinematics at CERN-ISOLDE. These nuclei have been proposed to lie in, or at the boundary of the region where the seniority scheme should persist. However, contributions from collective excitations are likely to be present when moving away from the N=126 closed shell. Such an effect is confirmed by the observed increased collectivity of the $2^{+}_{1}\rightarrow 0^{+}_{1}$ transitions. Experimental results have been interpreted with the aid of theoretical studies carried out within the BCS-based QRP…
Unraveling the nature of universal dynamics in O(N) theories
2020
Many-body quantum systems far from equilibrium can exhibit universal scaling dynamics which defy standard classification schemes. Here, we disentangle the dominant excitations in the universal dynamics of highly occupied N-component scalar systems using unequal-time correlators. While previous equal-time studies have conjectured the infrared properties to be universal for all N, we clearly identify for the first time two fundamentally different phenomena relevant at different N. We find all N >= 3 to be indeed dominated by the same Lorentzian "large-N" peak, whereas N = 1 is characterized instead by a non-Lorentzian peak with different properties, and for N = 2, we see a mixture of two cont…