Nonequilibrium Thermo Field Dynamics Using 4x4-Matrix Transformation for System with Bose--Einstein Condensation

T. Oyama; Y. Nakamura; Y. Yamanaka

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arXiv · 2105.11913

Nonequilibrium Thermo Field Dynamics Using 4x4-Matrix Transformation for System with Bose--Einstein Condensation

T. Oyama·Y. Nakamura·Y. Yamanaka

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Abstract

This study aims to construct a theoretical formulation of a nonequilibrium process for a system of Bose--Einstein condensate associated with a spontaneous symmetry breakdown. For this, Thermo Field Dynamics is used. We then describe the most general forms of a 4x4 transformation and an unperturbed Hamiltonian. After calculating the $4\times 4$ self-energy and identifying its on-shell, we impose the renormalization condition in which the entire on-shell self-energy should vanish. This condition provides a sufficient number of independent equations to determine all of the parameters in an unperturbed Hamiltonian, among which the quantum transport equations for normal and anomalous number distributions are included.

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BibTeX RIS

T. Oyama, Y. Nakamura, Y. Yamanaka. 2021-05-22. Nonequilibrium Thermo Field Dynamics Using 4x4-Matrix Transformation for System with Bose--Einstein Condensation. https://arxiv.org/abs/2105.11913

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