TY - JOUR
T1 - 4 × 4-matrix transformation for systems with spontaneous symmetry breakdown and self-consistent renormalization in nonequilibrium Thermo Field Dynamics
AU - Oyama, T.
AU - Nakamura, Y.
AU - Yamanaka, Y.
N1 - Funding Information:
The authors thank KEK Theory Center for offering us the opportunity to discuss this work during the KEK Theory workshop on “Thermal Quantum Field Theories and Their Applications”, and Dr. R. Imai for the discussions conducted at an early stage of this study.
Publisher Copyright:
© 2021 The Authors
PY - 2022/4/1
Y1 - 2022/4/1
N2 - 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 4 × 4-matrix transformation and an unperturbed Hamiltonian. After calculating the 4 × 4-matrix 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.
AB - 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 4 × 4-matrix transformation and an unperturbed Hamiltonian. After calculating the 4 × 4-matrix 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.
KW - Nonequilibrium
KW - Quantum field theory
KW - Quantum transport equation
KW - Renormalization
KW - Thermo Field Dynamics
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U2 - 10.1016/j.physa.2021.126732
DO - 10.1016/j.physa.2021.126732
M3 - Article
AN - SCOPUS:85122201987
SN - 0378-4371
VL - 591
JO - Physica A: Statistical Mechanics and its Applications
JF - Physica A: Statistical Mechanics and its Applications
M1 - 126732
ER -