Summary
In this work it is developed a method of approximation to calculate the excitation spectrum and the ground-state energy of an infinite system of interacting bosons at temperatureT=0. It is shown that this method is suitable for describing systems of interacting bosons which present condensation in single-particle states or in two-particle state. In both cases the excitation spectrum is gapless and the current is conserved.
Riassunto
Si sviluppa un metodo di approssimazione che permette di calcolare lo spettro di eccitazione e l’energia dello stato fondamentale di un sistema infinito di bosoni a temperatureT=0. Si mostra che facendo uso di tale metodo si possono descrivere sia sistemi che presentano condensazione in uno stato di singola particella che in stati di più particelle ottenendo sia nell’uno che nell’altro caso uno spettro di eccitazione senza gap e con conservazione della corrente.
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This research has been sponsored in part by the Gruppo di Napoli of the GNSM.
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Coniglio, A., Marinaro, M. Breakdown of symmetry and gapless spectrum in many-boson systems. Nuovo Cimento B (1965-1970) 48, 262–292 (1967). https://doi.org/10.1007/BF02712191
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DOI: https://doi.org/10.1007/BF02712191