Variational cluster approach for correlated many-body systems out of equilibrium

Research output: Contribution to conference(Old data) Lecture or PresentationResearch

Abstract

We present a
numerical approach that allows to compute
steady state properties of strongly correlated quantum many-body
systems out of equilibrium [1].
The method
is based on a combination of
variational cluster approach
with the nonequilibrium Green's function (Keldysh) formalism.

We apply the method to non-linear transport
across a strongly correlated quantum wire
described by the fermionic Hubbard model, and across a correlated
quantum dot [2].
In the last case, we benchmark
results for the steady-state current
with data from
Matrix Product State based time
evolution.
We show that for low to medium interaction strength,
a simple cluster perturbative approach
already yields good
results, while for larger interaction strength the
self-consistent
feedback provided by the variational condition
significantly enhances the accuracy.
Finally, we illustrate how the method bridges to nonequilibrium
cluster dynamical mean-field theory.
Original languageEnglish
Number of pages1
Publication statusPublished - 11 Oct 2012
EventCorrelations and coherence in quantum systems -
Duration: 11 Oct 2012 → …

Conference

ConferenceCorrelations and coherence in quantum systems
Period11/10/12 → …

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data products
Green's functions
interactions
formalism

Cite this

Variational cluster approach for correlated many-body systems out of equilibrium. / Arrigoni, Enrico.

2012. Correlations and coherence in quantum systems, .

Research output: Contribution to conference(Old data) Lecture or PresentationResearch

Arrigoni, E 2012, 'Variational cluster approach for correlated many-body systems out of equilibrium' Correlations and coherence in quantum systems, 11/10/12, .
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N2 - We present a numerical approach that allows to computesteady state properties of strongly correlated quantum many-bodysystems out of equilibrium [1].The method is based on a combination of variational cluster approach with the nonequilibrium Green's function (Keldysh) formalism.We apply the method to non-linear transport across a strongly correlated quantum wiredescribed by the fermionic Hubbard model, and across a correlatedquantum dot [2].In the last case, we benchmark results for the steady-state currentwith data fromMatrix Product State based timeevolution. We show that for low to medium interaction strength, a simple cluster perturbative approach already yields goodresults, while for larger interaction strength the self-consistentfeedback provided by the variational conditionsignificantly enhances the accuracy. Finally, we illustrate how the method bridges to nonequilibrium cluster dynamical mean-field theory.

AB - We present a numerical approach that allows to computesteady state properties of strongly correlated quantum many-bodysystems out of equilibrium [1].The method is based on a combination of variational cluster approach with the nonequilibrium Green's function (Keldysh) formalism.We apply the method to non-linear transport across a strongly correlated quantum wiredescribed by the fermionic Hubbard model, and across a correlatedquantum dot [2].In the last case, we benchmark results for the steady-state currentwith data fromMatrix Product State based timeevolution. We show that for low to medium interaction strength, a simple cluster perturbative approach already yields goodresults, while for larger interaction strength the self-consistentfeedback provided by the variational conditionsignificantly enhances the accuracy. Finally, we illustrate how the method bridges to nonequilibrium cluster dynamical mean-field theory.

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