Uncertainty principle for experimental measurements: Fast versus slow probes

Hansmann, P.; Ayral, Thomas; Tejeda, Antonio; Biermann, Silke

doi:10.1038/srep19728

Cited by 16 publications

(18 citation statements)

References 66 publications

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“…In fact, the results obtained in the simplified "dual" approaches that include at least the electron-boson vertex γ are similar to those obtained by the GW +EDMFT method, which is conceptually and practically simpler than dual methods and has hence already been applied to realistic materials in a number of works [53][54][55][56].…”

Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexsupporting

confidence: 56%

Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

et al. 2017

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In electronic systems with long-range Coulomb interaction, the nonlocal Fock-exchange term has a bandwidening effect. While this effect is included in combined many-body perturbation theory and dynamical mean field theory (DMFT) schemes, it is not taken into account in standard extended DMFT (EDMFT) calculations. Here, we include this instantaneous term in both approaches and investigate its effect on the phase diagram and dynamically screened interaction. We show that the largest deviations between previously presented EDMFT and GW +EDMFT results originate from the nonlocal Fock term, and that the quantitative differences are especially large in the strong-coupling limit. Furthermore, we show that the charge-ordering phase diagram obtained in GW +EDMFT methods for moderate interaction values is very similar to the one predicted by dual-boson methods that include the fermion-boson or four-point vertex. DOI: 10.1103/PhysRevB.95.245130 Dynamical mean field theory (DMFT) [1] self-consistently maps a correlated Hubbard lattice problem with local interactions onto an effective impurity problem consisting of a correlated orbital hybridized with a noninteracting fermionic bath. If the bath is integrated out, one obtains an impurity action with retarded hoppings. Extended dynamical mean field theory [2-10] (EDMFT) extends the DMFT idea to systems with long-range interactions. It does so by mapping a lattice problem with long-range interactions onto an effective impurity model with self-consistently determined fermionic and bosonic baths, or, in the action formulation, an impurity model with retarded hoppings and retarded interactions.While EDMFT captures dynamical screening effects and charge-order instabilities, it has been found to suffer from qualitative shortcomings in finite dimensions. For example, the charge susceptibility computed in EDMFT does not coincide with the derivative of the average charge with respect to a small applied field [11], nor does it obey local charge conservation rules [12] essential for an adequate description of collective modes such as plasmons.The EDMFT formalism has an even more basic deficiency: since it is based on a local approximation to the self-energy, it does not include even the first-order nonlocal interaction term, the Fock term. The combined GW +EDMFT [13][14][15] scheme corrects this by supplementing the local self-energy from EDMFT with the nonlocal part of the GW diagram, where G is the interacting Green's function and W the fully screened interaction. Indeed, the nonlocal Fock term [Gv] nonloc is included in the nonlocal [GW ] nonloc diagram. As described in more detail in Ref. [15] (see also the appendix of Ref.[16]), the GW +EDMFT method is formally obtained by constructing an energy functional of G and W , the Almbladh [17] functional , and by approximating as a sum of two terms, one containing all local diagrams (corresponding to EDMFT) and the other containing the simplest nonlocal correction (corresponding to the GW approximation [18]). This functional construct...

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Section: Beyond Gw+edmft: Comparison To Dual Bosons and Trilexsupporting

confidence: 56%

Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

et al. 2017

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“…As a result graphene for example appears metallic, even though it would be on the verge of the insulating state if only the local Coulomb interaction was considered (Wehling et al, 2011). For certain surface systems, the nonlocal interaction may also exhibit a slow 1/r decay with distance r, rendering long-range contributions important (Hansmann et al, 2016(Hansmann et al, , 2013.…”

Section: E Non-local Interactions and Multiorbitalsmentioning

confidence: 99%

Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory

et al. 2018

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Strong electronic correlations pose one of the biggest challenges to solid state theory. Recently developed methods that address this problem by starting with the local, eminently important correlations of dynamical mean field theory (DMFT) are reviewed. In addition, nonlocal correlations on all length scales are generated through Feynman diagrams, with a local two-particle vertex instead of the bare Coulomb interaction as a building block. With these diagrammatic extensions of DMFT long-range charge-, magnetic-, and superconducting fluctuations as well as (quantum) criticality can be addressed in strongly correlated electron systems. An overview is provided of the successes and results achieved mainly for model Hamiltonians and an outline is given of future prospects for realistic material calculations. PACS numbers: 71.10.-w,71.10.Fd,71.27.+a CONTENTS 42 5. One and zero dimensions 43 B. Heavy fermions and Kondo lattice model (KLM) 44 C. Falicov-Kimball (FK) model 45 D. Models of Disorder 47 E. Non-local interactions and multiorbitals 48 V. Open source implementations 51 VI. Conclusion and outlook 51 References 53 arXiv:1705.00024v2 [cond-mat.str-el]

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“…There are two complimentary (as we will discuss below) ways of stabilizing the system that both result in a gapped electronic structure: the adatoms may undergo a Jahn-Teller-like distortion leading to a superstructure with inequivalent dangling bond orbitals, or Mott-Hubbard physics may open a gap between the filled and the unoccupied part of the electronic structure. Recently, not only the ground state of strongly correlated systems, but also their dynamics on ultra-short time scales has come into focus of experimental investigations [4,5]. Therefore, understanding the elementary excitations and their interplay, which determines the lifetime of excited states, has become an issue of current interest.…”

Section: Introductionmentioning

confidence: 99%

“…Since the excited state is predicted to be sufficiently long-lived, such an experiment could provide information not only about the valence bands, but also about the dispersion of the unoccupied bands and their relative position with respect to the valence band maximum. Moreover, detecting the electrons both from single-photon as well as two-photon photoemission from the same sample could resolve ambiguities about the size of the band gap in this muchstudied system, and provide useful data to be compared with many-body calculations [4,9,17] of the band structure.…”

Section: Introductionmentioning

confidence: 99%

Phonon-induced electronic relaxation in a strongly correlated system: The Sn/Si(111) (3×3) adlayer revisited

Zahedifar

Kratzer

2019

Phys. Rev. B

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The ordered adsorbate layer Sn/Si(111) ( √ 3 × √ 3) with coverage of one third of a monolayer is considered as a realization of strong electronic correlation in surface physics. Our theoretical analysis shows that electronhole pair excitations in this system can be long-lived, up to several hundred nanoseconds, since the decay into surface phonons is found to be a highly non-linear process. We combine first-principles calculations with help of a hybrid functional (HSE06) with modeling by a Mott-Hubbard Hamiltonian coupled to phononic degrees of freedom. The calculations show that the Sn/Si(111) ( √ 3 × √ 3) surface is insulating and the two Sn-derived bands inside the substrate band gap can be described as the lower and upper Hubbard band in a Mott-Hubbard model with U = 0.75 eV. Furthermore, phonon spectra are calculated with particular emphasis on the Sn-related surface phonon modes. The calculations demonstrate that the adequate treatment of electronic correlations leads to a stiffening of the wagging mode of neighboring Sn atoms; thus, we predict that the onset of electronic correlations at low temperature should be observable in the phonon spectrum, too. The deformation potential for electron-phonon coupling is calculated for selected vibrational modes and the decay rate of an electron-hole excitation into multiple phonons is estimated, substantiating the very long lifetime of these excitations.

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Uncertainty principle for experimental measurements: Fast versus slow probes

Cited by 16 publications

References 66 publications

Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

Diagrammatic routes to nonlocal correlations beyond dynamical mean field theory

Phonon-induced electronic relaxation in a strongly correlated system: The Sn/Si(111) (3×3) adlayer revisited

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