Single-particle and collective excitations inNi62

Single Particle and Collective Spin Excitations in Semimagnetic Quantum Wells

Collective and single-particle spin-flip excitations of a two-dimensional electron gas in a semimagnetic Cd1−xMnxTe quantum well are observed by resonant Raman scattering. Application of a magnetic field splits the spin-subbands and a spin-polarization is induced in the electron gas. Above some critical field, a collective spin-flip mode, which disperses with in-plane wave vector, dominates the...

Single Particle versus Collective Electronic Excitations 1 Philip

As a rst approximation, a metal can be modelled as an electron gas. A non-interacting electron gas has a continuous spectrum of electron-hole pair excitations. At each wavevector ~ Q with j~ Qj less than the maximum Fermi surface spanning vector (2kF ) there is a continuous set of electron-hole pair states, with a maximum energy but no gap (the minimum energy is zero.) Once the Coulomb interact...

Interfacing collective atomic excitations and single photons.

We study the performance and limitations of a coherent interface between collective atomic states and single photons. A quantized spin-wave excitation of an atomic sample inside an optical resonator is prepared probabilistically, stored, and adiabatically converted on demand into a sub-Poissonian photonic excitation of the resonator mode. The measured peak single-quantum conversion efficiency o...

Self–consistent Dual Boson approach to single-particle and collective excitations in correlated systems

Single-Particle Excitations in Narrow Energy Bands

Hubbard's model for studying correlation effects in systems with narrow energy bands is analyzed by means of a technique which allows the calculation of moments of the individual peaks in the spectral weight function for single-particle excitations. The analysis of the zeroth moments of the peaks shows that the total weight in the bands depends on the strength of the kinetic-energy term in the ...