Excited states in superfluid4He: a Monte Carlo approach

Cechoslovackij fiziceskij zurnal - Tập 46 Số 1 - Trang 273-274 - 1996
Boronat, Jordi1, Casulleras, Joaquim1, Giorgini, Stefano1,2
1Department de Física i Enginyeria Nuclear, Campus Nord B4-B5, Universitat Politècnica de Catalunya, Barcelona, Spain
2Dipartimento di Fisica, Università di Trento, Povo, Italy

Tóm tắt

We present diffusion Monte Carlo calculations of the phonon-roton spectrum and the vortex excitation in liquid4He. The sign problem associated with the excited state is solved in the framework of the fixed node approximation. Within this approximation it is shown that DMC improves in a significant way the well known variational predictions for the phonon-roton spectrum. Results for the core energy and density profile of a 2D vortex are also presented with an efficient method to work out the infinite extension of the phase present in the Feynman wave function. Finally we show how so the fixed node bounds are improved towards the exact values when the nodal surface is released.

Tài liệu tham khảo

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