Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems

Using closed-time-path two-particle irreducible coarse-grained effective action (CTP 2PI CGEA) techniques, we study the response of an open interacting electronic system to time-dependent external electromagnetic fields. We show that the CTP 2PI CGEA is invariant under a simultaneous gauge transform...

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Autores principales: Peralta-Ramos, J., Calzetta, E.
Formato: JOUR
Materias:
Arbitrary orders
Bethe-salpeter equations
Closed time paths
Coarse-grained
Current fluctuations
Driven systems
Dyson equations
Electronic currents
Electronic systems
Expectation values
External electromagnetic fields
External fields
Gauge transformations
Nonlinear currents
Nonlinear response theories
Response functions
Time dependents
Electromagnetic fields
Gages
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09538984_v21_n21_p_PeraltaRamos
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_09538984_v21_n21_p_PeraltaRamos2023-10-03T15:51:29Z Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems Peralta-Ramos, J. Calzetta, E. Arbitrary orders Bethe-salpeter equations Closed time paths Coarse-grained Current fluctuations Driven systems Dyson equations Electronic currents Electronic systems Expectation values External electromagnetic fields External fields Gauge transformations Nonlinear currents Nonlinear response theories Response functions Time dependents Electromagnetic fields Gages Using closed-time-path two-particle irreducible coarse-grained effective action (CTP 2PI CGEA) techniques, we study the response of an open interacting electronic system to time-dependent external electromagnetic fields. We show that the CTP 2PI CGEA is invariant under a simultaneous gauge transformation of the external field and the full Schwinger-Keldysh propagator, and that this property holds even when the loop expansion of the CTP 2PI CGEA is truncated at arbitrary order. The effective action approach provides a systematic way of calculating the propagator and response functions of the system, via the Schwinger-Dyson equation and the Bethe-Salpeter equations, respectively. We show that, due to the invariance of the CTP 2PI CGEA under external gauge transformations, the response functions calculated from it satisfy the Ward-Takahashi hierarchy, thus warranting the conservation of the electronic current beyond the expectation value level. We also clarify the connection between nonlinear response theory and the WT hierarchy, and discuss an example of an ad hoc approximation that violates it. These findings may be useful in the study of current fluctuations in correlated electronic pumping devices. © 2009 IOP Publishing Ltd. Fil:Peralta-Ramos, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Calzetta, E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09538984_v21_n21_p_PeraltaRamos
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Arbitrary orders
Bethe-salpeter equations
Closed time paths
Coarse-grained
Current fluctuations
Driven systems
Dyson equations
Electronic currents
Electronic systems
Expectation values
External electromagnetic fields
External fields
Gauge transformations
Nonlinear currents
Nonlinear response theories
Response functions
Time dependents
Electromagnetic fields
Gages
spellingShingle Arbitrary orders
Bethe-salpeter equations
Closed time paths
Coarse-grained
Current fluctuations
Driven systems
Dyson equations
Electronic currents
Electronic systems
Expectation values
External electromagnetic fields
External fields
Gauge transformations
Nonlinear currents
Nonlinear response theories
Response functions
Time dependents
Electromagnetic fields
Gages
Peralta-Ramos, J.
Calzetta, E.
Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems
topic_facet Arbitrary orders
Bethe-salpeter equations
Closed time paths
Coarse-grained
Current fluctuations
Driven systems
Dyson equations
Electronic currents
Electronic systems
Expectation values
External electromagnetic fields
External fields
Gauge transformations
Nonlinear currents
Nonlinear response theories
Response functions
Time dependents
Electromagnetic fields
Gages
description Using closed-time-path two-particle irreducible coarse-grained effective action (CTP 2PI CGEA) techniques, we study the response of an open interacting electronic system to time-dependent external electromagnetic fields. We show that the CTP 2PI CGEA is invariant under a simultaneous gauge transformation of the external field and the full Schwinger-Keldysh propagator, and that this property holds even when the loop expansion of the CTP 2PI CGEA is truncated at arbitrary order. The effective action approach provides a systematic way of calculating the propagator and response functions of the system, via the Schwinger-Dyson equation and the Bethe-Salpeter equations, respectively. We show that, due to the invariance of the CTP 2PI CGEA under external gauge transformations, the response functions calculated from it satisfy the Ward-Takahashi hierarchy, thus warranting the conservation of the electronic current beyond the expectation value level. We also clarify the connection between nonlinear response theory and the WT hierarchy, and discuss an example of an ad hoc approximation that violates it. These findings may be useful in the study of current fluctuations in correlated electronic pumping devices. © 2009 IOP Publishing Ltd.
format JOUR
author Peralta-Ramos, J.
Calzetta, E.
author_facet Peralta-Ramos, J.
Calzetta, E.
author_sort Peralta-Ramos, J.
title Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems
title_short Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems
title_full Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems
title_fullStr Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems
title_full_unstemmed Two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems
title_sort two-particle irreducible effective action approach to nonlinear current-conserving approximations in driven systems
url http://hdl.handle.net/20.500.12110/paper_09538984_v21_n21_p_PeraltaRamos
work_keys_str_mv AT peraltaramosj twoparticleirreducibleeffectiveactionapproachtononlinearcurrentconservingapproximationsindrivensystems
AT calzettae twoparticleirreducibleeffectiveactionapproachtononlinearcurrentconservingapproximationsindrivensystems
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