科研之友
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摘要
We present a full set of wave equations describing a dense Bose fluid, applicable both to non-ideal gases and to liquid He-4. The phonon spectrum in liquid He-4 is found and the fraction of condensed particles is calculated at zero temperature for a wide range of densities. The theory also yields the ground-state energy for the quantum liquid He-4 in agreement to high accuracy with Monte Carlo simulations and experimental data at low pressure. A new and essential point is the the introduction of a momentum space cutoff at the speed of the second sound. We also present the derivation of a generalized Hartree-Fock equation describing roton clusters in low temperature liquid He-4, allowing us to confirm that, at low enough temperatures and for a wide range of pressures, the stable clusters consist of 13 bound atoms.
- 出版日期2014-7-24
