Quantum criticality and population trapping of fermions by non-equilibrium lattice modulations

Frank, Regine

doi:10.1088/1367-2630/15/12/123030

Cited by 22 publications

(37 citation statements)

References 35 publications

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“…This expression helps to understand why one obtains a positive spectral function upon summing over all Floquet indices ℓ and j as done in Ref. 16. Clearly…”

mentioning

confidence: 85%

Positivity of the Spectral Densities of Retarded Floquet Green Functions

2019

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Periodically driven nonequilibrium many-body systems are interesting because they have a quasienergy spectra, which can be tailored by controlling the external driving fields. We derive the general spectral representation of retarded Green functions in the Floquet regime, thereby generalizing the well-known Lehmann representation from equilibrium many-body physics. The derived spectral Floquet representation allows us to prove the nonnegativity of spectral densities and to determine exact spectral sum rules, which can be employed to benchmark the accuracy of approximations to the exact Floquet many-body Green functions.

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“…This expression helps to understand why one obtains a positive spectral function upon summing over all Floquet indices ℓ and j as done in Ref. 16. Clearly…”

mentioning

confidence: 85%

Positivity of the Spectral Densities of Retarded Floquet Green Functions

2019

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“…It yields Green's functions which depend on two separate time arguments. The double Fourier transform from time to frequency coordinates leads to two separate frequencies which are chosen as relative and center-of-mass frequency [30,31,34,35] and we can thus expand the underlying physical procedures into Floquet modes, the graphical explanation is found in Figure 2a,…”

Section: Hubbard Model For Excitons and Exciton-polaritonsmentioning

confidence: 99%

“…We model the coupling of the classical laser,hΩ L = 1.75 eV, to the quantum many body system as well as higher-order photon absorption processes,hΩ L = 3.5 eV etc., by means of the Floquet matrix [28][29][30][31]. The band structure and the lifetimes of light-matter coupled states are derived by the Dynamical Mean Field Theory (DMFT) [32][33][34][35] in the sense of a generalized Hubbard-Hamiltonian out-of thermodynamical equilibrium. The Hubbard Hamiltonion includes strictly local interactions between electrons with opposite spins.…”

Section: Introductionmentioning

confidence: 99%

Quantum Many-Body Theory for Exciton-Polaritons in Semiconductor Mie Resonators in the Non-Equilibrium

Lubatsch

Frank

2020

Applied Sciences

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We implement externally excited ZnO Mie resonators in a framework of a generalized Hubbard Hamiltonian to investigate the lifetimes of excitons and exciton-polaritons out of thermodynamical equilibrium. Our results are derived by a Floquet-Keldysh-Green's formalism with Dynamical Mean Field Theory (DMFT) and a second order iterative perturbation theory solver (IPT). We find that the Fano resonance which originates from coupling of the continuum of electronic density of states to the semiconductor Mie resonator yields polaritons with lifetimes between 0.6 ps and 1.45 ps. These results are compared to ZnO polariton lasers and to ZnO random lasers. We interpret the peaks of the exciton-polariton lifetimes in our results as a sign of gain narrowing which may lead to stable polariton lasing modes in the single excited ZnO Mie resonator. This form of gain may lead to polariton random lasing in an ensemble of ZnO Mie resonators in the non-equilibrium. PACS: 42.55.-f lasers; 71.10.-w theories and models of many-electron systems; 42.50.Hz strong-field excitation of optical transitions in quantum systems; multi-photon processes; dynamic Stark shift; 74.40+ Fluctuations; 03.75.Lm Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations; 72.20.Ht high-field and nonlinear effects; 71.36.+c polaritons; 71.35.-y excitons and related phenomena; 42.55.Px semiconductor lasers, laser diodes; 89.75.-k complex systems

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“…The expansion into Floquet modes with the proper Keldysh description models the external time dependent classical driving field, see 1.1, and couples it to the quantum many body system. We numerically solve the Floquet-Keldysh DMFT [40,51] with a second order iterative perturbation theory (IPT), where the the local self-energy Σ αβ is derived by four bubble diagrams, see Fig. 5.…”

Section: Dynamical Mean Field Theory In the Non-equilibriummentioning

confidence: 99%

“…The couplingd · E 0 cos(Ω L τ) generates a factor Ω L that cancels the 1/Ω L in the renormalized cylindrical Bessel function in Equation (7) of ref. [51] in the Coulomb gauge,…”

Section: Dynamical Mean Field Theory In the Non-equilibriummentioning

confidence: 99%

Behavior of Floquet Topological Quantum States in Optically Driven Semiconductors

Lubatsch¹,

Frank²

2019

Preprint

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Spatially uniform optical excitations can induce Floquet topological band structures within insulators which can develop similar or equal characteristics as are known from three-dimensional topological insulators. We derive in this article theoretically the development of Floquet topological quantum states for electromagnetically driven semiconductor bulk matter and we present results for the lifetime of these states and their occupation in the non-equilibrium. The direct physical impact of the mathematical precision of the Floquet-Keldysh theory is evident when we solve the driven system of a generalized Hubbard model with our framework of dynamical mean field theory (DMFT) in the non-equilibrium for a case of ZnO. The physical consequences of the topological non-equilibrium effects in our results for correlated systems are explained with their impact on optoelectronic applications. PACS: 71.10.-w Theories and models of many-electron systems; 42.50.Hz Strong-field excitation of optical transitions in quantum systems; multi-photon processes; dynamic Stark shift; 74.40+ Fluctuations; 03.75.Lm Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations; 72.20.Ht High-field and nonlinear effects; 89.75.-k Complex systems

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Quantum criticality and population trapping of fermions by non-equilibrium lattice modulations

Cited by 22 publications

References 35 publications

Positivity of the Spectral Densities of Retarded Floquet Green Functions

Positivity of the Spectral Densities of Retarded Floquet Green Functions

Quantum Many-Body Theory for Exciton-Polaritons in Semiconductor Mie Resonators in the Non-Equilibrium

Behavior of Floquet Topological Quantum States in Optically Driven Semiconductors

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