We have studied dynamic properties of a system of hard-sphere bosons at zero temperature through ab-initio estimations of the dynamic structure factor, S(q,w), from the dilute regime up to a strongly interacting regime, paroganable to overpressurized liquid helium. To this extent, we have used the Genetic Inversion via Falsification of Theories (GIFT) algorithm [1], which perform accurate analytic continuations of imaginary time correlation functions under ill-posed conditions. The imaginary time correlation functions have been computed with an exact numerical method, the path integral ground state (PIGS) method [2]. With increasing density, we observe a crossover of the dispersion of elementary excitations from a Bogoliubov-like spectrum to a phonon-maxon-roton curve, characteristic of superfluid helium, and the emergence of a broad multiphonon contribution accompanying the quasi-particle peak. References: [1] E. Vitali, M. Rossi, L. Reatto and D.E. Galli, Phys. Rev. B 82, 174510,(2010). [2] A. Sarsa, K. E. Schmidt, and W. R. Magro, J. Chem. Phys. 113, 1366 (2000).

Quantum Monte Carlo study of dynamics : from weakly interacting Bose gas to helium-like Bose fluid / F. Tramonto, R. Rota, D.E. Galli, S. Giorgini. ((Intervento presentato al 1. convegno Workshop : Condensed matter highlights by the structure of matter research group tenutosi a Milano nel 2013.

Quantum Monte Carlo study of dynamics : from weakly interacting Bose gas to helium-like Bose fluid

F. Tramonto;D.E. Galli
Penultimo
;
2013

Abstract

We have studied dynamic properties of a system of hard-sphere bosons at zero temperature through ab-initio estimations of the dynamic structure factor, S(q,w), from the dilute regime up to a strongly interacting regime, paroganable to overpressurized liquid helium. To this extent, we have used the Genetic Inversion via Falsification of Theories (GIFT) algorithm [1], which perform accurate analytic continuations of imaginary time correlation functions under ill-posed conditions. The imaginary time correlation functions have been computed with an exact numerical method, the path integral ground state (PIGS) method [2]. With increasing density, we observe a crossover of the dispersion of elementary excitations from a Bogoliubov-like spectrum to a phonon-maxon-roton curve, characteristic of superfluid helium, and the emergence of a broad multiphonon contribution accompanying the quasi-particle peak. References: [1] E. Vitali, M. Rossi, L. Reatto and D.E. Galli, Phys. Rev. B 82, 174510,(2010). [2] A. Sarsa, K. E. Schmidt, and W. R. Magro, J. Chem. Phys. 113, 1366 (2000).
Settore FIS/03 - Fisica della Materia
Università degli Studi di Milano
https://docs.google.com/file/d/0B5eztodZ3Y3wWF9Pejh0VE9tQzg/edit?usp=sharing
Quantum Monte Carlo study of dynamics : from weakly interacting Bose gas to helium-like Bose fluid / F. Tramonto, R. Rota, D.E. Galli, S. Giorgini. ((Intervento presentato al 1. convegno Workshop : Condensed matter highlights by the structure of matter research group tenutosi a Milano nel 2013.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/230102
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