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Response functions of cold neutron matter: density, spin and current fluctuations
- Publication Year :
- 2012
-
Abstract
- We study the response of a single-component pair-correlated baryonic Fermi-liquid to density, spin, and their current perturbations. A complete set of response functions is derived in the low-temperature regime both within an effective theory based on a small momentum transfer expansion and within a numerical scheme valid for arbitrary momentum transfers. A comparison of these two approaches validates the perturbative approximation within the domain of its convergence. We derive the spectral functions of collective excitations associated with the density, density-current, spin, and spin-current perturbations. The dispersion relations of density and spin fluctuations are derived and it is shown that the density fluctuations lead to exciton-like undamped bound states, whereas the spin excitations correspond to diffusive modes above the pair-breaking threshold. The contribution of the collective pair-breaking modes to the specific heat of neutron matter at subnuclear densities is computed and is shown to be comparable to that of the degenerate electron gas at not too low temperatures.<br />18 pages, 5 figures, v2: matches published version
- Subjects :
- Physics
Nuclear and High Energy Physics
Spin polarization
Nuclear Theory
Momentum transfer
Degenerate energy levels
FOS: Physical sciences
Momentum
Nuclear Theory (nucl-th)
Astrophysics - Solar and Stellar Astrophysics
Quantum mechanics
Dispersion relation
Quantum electrodynamics
Quasiparticle
Fermi gas
Solar and Stellar Astrophysics (astro-ph.SR)
Spin-½
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....11cd18304c3fcad1717759984fa681d2