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Title: Microscopic calculations of the excitation spectrum of one 3He impurity in liquid 4He
Author: Fabrocini, A.
Fantoni, S.
Rosati, Sergio
Polls Martí, Artur
Keywords: Microscòpia de materials
Heli líquid
Pertorbació (Dinàmica quàntica)
Microscopy of materials
Liquid helium
Perturbation (Quantum dynamics)
Issue Date: 1986
Publisher: The American Physical Society
Abstract: We calculate the chemical potential ¿0 and the effective mass m*/m3 of one 3He impurity in liquid 4He. First a variational wave function including two- and three-particle dynamical correlations is adopted. Triplet correlations bring the computed values of ¿0 very close to the experimental results. The variational estimate of m*/m3 includes also backflow correlations between the 3He atom and the particles in the medium. Different approximations for the three-particle distribution function give almost the same values for m*/m3. The variational approach underestimates m*/m3 by ~10% at all of the considered densities. Correlated-basis perturbation theory is then used to improve the wave function to include backflow around the particles of the medium. The perturbative series built up with one-phonon states only is summed up to infinite order and gives results very close to the variational ones. All the perturbative diagrams with two independent phonons have then been summed to compute m*/m3. Their contribution depends to some extent on the form used for the three-particle distribution function. When the scaling approximation is adopted, a reasonable agreement with the experimental results is achieved.
Note: Reproducció digital del document publicat en format paper, proporcionada per PROLA i
It is part of: Physical Review B, 1986, vol. 33, núm. 9, p. 6057-6067.
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ISSN: 0163-1829
Appears in Collections:Articles publicats en revistes (Física Quàntica i Astrofísica)

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