A5074990231- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Quantum and electron transport phenomena
- Magnetic and transport properties of perovskites and related materials
- Quantum many-body systems
- Theoretical and Computational Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Rare-earth and actinide compounds
- Iron-based superconductors research
- Advanced Chemical Physics Studies
- Quantum Computing Algorithms and Architecture
- Topological Materials and Phenomena
- Organic and Molecular Conductors Research
- Quantum, superfluid, helium dynamics
- Magnetic Properties of Alloys
- Fullerene Chemistry and Applications
- Spectral Theory in Mathematical Physics
- Electronic and Structural Properties of Oxides
- Quantum chaos and dynamical systems
- Diamond and Carbon-based Materials Research
- Advanced Thermodynamics and Statistical Mechanics
- Atomic and Subatomic Physics Research
- Inorganic Fluorides and Related Compounds
- Superconductivity in MgB2 and Alloys
- Molecular Junctions and Nanostructures
Collège de France
2016-2025
Centre National de la Recherche Scientifique
2016-2025
Centre de Physique Théorique
2016-2025
École Polytechnique
2015-2025
Centre de Physique Théorique
2008-2024
Laboratoire de Physique Théorique de la Matière Condensée
2020-2023
Université Paris-Saclay
2016-2019
Institut de Physique
2018
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2009
CEA Paris-Saclay
2009
We present an approach that combines the local-density approximation (LDA) and dynamical mean-field theory (DMFT) in framework of full-potential linear augmented plane-wave method. Wannier-type functions for correlated shell are constructed by projecting local orbitals onto a set Bloch eigenstates located within certain energy window. The screened Coulomb interaction Hund's coupling calculated from first-principles constrained random-phase scheme. apply this $\text{LDA}+\text{DMFT}$...
Numerical results for ground-state and excited-state properties (energies, double occupancies, Matsubara-axis self-energies) of the single-orbital Hubbard model on a two-dimensional square lattice are presented, in order to provide an assessment our ability compute accurate thermodynamic limit. Many methods employed, including auxiliary-field quantum Monte Carlo, bare bold-line diagrammatic method dual fermions, density matrix embedding theory, renormalization group, dynamical cluster...
We investigate transport in strongly correlated metals. Within dynamical mean-field theory, we calculate the resistivity, thermopower, optical conductivity and thermodynamic properties of a hole-doped Mott insulator. Two well-separated temperature scales are identified: ${T}_{\mathrm{FL}}$ below which Landau Fermi liquid behavior applies, ${T}_{\mathrm{MIR}}$ above resistivity exceeds Mott-Ioffe-Regel value bad-metal is found. show that quasiparticle excitations remain well defined dominate...
The Hubbard model represents the fundamental for interacting quantum systems and electronic correlations. Using two-dimensional half-filled at weak coupling as a testing ground, we perform comparative study of comprehensive set state-of-the-art many-body methods. Upon cooling into its insulating antiferromagnetic ground state, hosts rich sequence distinct physical regimes with crossovers between high-temperature incoherent regime, an intermediate-temperature metallic low-temperature regime...
We study the expansion of single-particle and two-particle imaginary-time Matsubara Green's functions quantum impurity models in basis Legendre orthogonal polynomials. discuss various applications within dynamical mean-field theory (DMFT) framework. The method provides a more compact representation than standard frequencies, therefore significantly reduces memory-storage size these quantities. Moreover, it can be used as an efficient noise filter for physical quantities continuous-time Monte...
Cluster dynamical mean-field calculations based on 2-, 4-, 8-, and 16-site clusters are used to analyze the doping-driven metal-insulator transition in two-dimensional Hubbard model. Comparison of results obtained different enables a determination those aspects physics that common all permits identification artifacts associated with particular cluster geometries. A modest particle-hole asymmetry underlying band structure is shown lead qualitatively behavior hole-doped side than...
The Luttinger-Ward functional Φ[G], which expresses the thermodynamic grand potential in terms of interacting single-particle Green's function G, is found to be ill defined for fermionic models with Hubbard on-site interaction. In particular, we show that self-energy Σ[G]∝δΦ[G]/δG not a single-valued G: addition physical solution Σ[G], there exists at least one qualitatively distinct unphysical branch. This result demonstrated several models: atom, Anderson impurity model, and full...
We present an approach to the normal state of cuprate superconductors which is based on a minimal cluster extension dynamical mean-field theory. Our effective two-impurity model embedded in self-consistent bath. The two degrees freedom this can be associated nodal and antinodal regions momentum space. find metal-insulator transition selective At low doping, quasiparticles are destroyed region, while they remain protected leading formation apparent Fermi arcs. compare our results tunneling...
We introduce a method for summing Feynman's perturbation series based on diagrammatic Monte Carlo that significantly improves its convergence properties. This allows us to investigate in controllable manner the pseudogap regime of Hubbard model and study nodal/antinodal dichotomy at low doping intermediate coupling. Marked differences from weak coupling scenario are manifest, such as higher degree incoherence antinodes than `hot spots'. Our results show reduction quasiparticle coherence...
One of the distinctive features hole-doped cuprate superconductors is onset a `pseudogap' below temperature $T^*$. Recent experiments suggest that there may be connection between existence pseudogap and topology Fermi surface. Here, we address this issue by studying two-dimensional Hubbard model with two distinct numerical methods. We find only exists when surface hole-like that, for broad range parameters, its opening concomitant change from electron- to hole-like. identify common link...
We investigate the interplay of spin-orbit coupling (SOC) and electronic correlations in Sr_{2}RuO_{4} using dynamical mean-field theory. find that SOC does not affect correlation-induced renormalizations, which validates Hund's metal picture ruthenates even presence sizable relevant to these materials. Nonetheless, is found change significantly structure at k points where a degeneracy applies its absence. explain why two observations are consistent with one another calculate effects on...
The physics of the triangular lattice Hubbard model exhibits a rich phenomenology, ranging from metal-insulator transition, intriguing thermodynamic behavior, and putative spin liquid phase at intermediate coupling, ultimately becoming magnetic insulator strong coupling. In this multimethod study, we combine finite-temperature tensor network method, minimally entangled thermal typical states (METTS), with two Green-function-based methods, connected-determinant diagrammatic Monte Carlo...
We compute the electronic Green's function of topologically ordered Higgs phase a SU(2) gauge theory fluctuating antiferromagnetism on square lattice. The results are compared with cluster extensions dynamical mean field theory, and quantum Monte Carlo calculations, pseudogap strongly interacting hole-doped Hubbard model. Good agreement is found in momentum, frequency, hopping, doping dependencies spectral self-energy. show that lines (approximate) zeros zero-frequency signs underlying...
The relationship between the pseudogap and underlying ground-state phases has not yet been rigorously established. We investigated doped two-dimensional Hubbard model at finite temperature using controlled diagrammatic Monte Carlo calculations, allowing for computation of spectral properties in infinite-size limit with arbitrary momentum resolution. found three distinct regimes as a function doping interaction strength: weakly correlated metal, metal strong effects, regime low doping. show...
We establish the phase diagram of Hubbard model on a cubic lattice for wide range temperatures, dopings and interaction strengths, considering both commensurate incommensurate magnetic orders. use dynamical mean-field theory together with an efficient method to compute free energy which enable determination correct ordering vectors. Besides antiferromagnetic state close half-filling, we identify number different spiral phases vectors $(q,\pi,\pi)$, $(q,q,\pi)$ $(q,q,q)$ as well region...
We investigate the momentum-resolved spin and charge susceptibilities, as well chemical potential double occupancy in two-dimensional Hubbard model functions of doping, temperature, interaction strength. Through these quantities, we identify a weak-coupling regime, strong-coupling regime with short-range correlations an intermediate-coupling long magnetic correlation lengths. In channel, observe additional crossover from commensurate to incommensurate correlations. contrast, find be only...
The Luttinger-Ward functional (LWF) has been a starting point for conserving approximations in many-body physics 50 years. recent discoveries of its multivaluedness and the associated divergence two-particle irreducible vertex function $\mathrm{\ensuremath{\Gamma}}$ have revealed an inherent limitation this approach. Here we demonstrate how these undesirable properties LWF can lead to failure computational methods based on approximation LWF. We apply nested cluster scheme (NCS) Hubbard model...
Understanding the Fermi surface and low-energy excitations of iron or cobalt pnictides is crucial for assessing electronic instabilities such as magnetic superconducting states. Here, we propose implement a new approach to compute properties correlated electron materials, taking into account both screened exchange beyond local density approximation dynamical correlations. The scheme allows us resolve puzzle ${\mathrm{BaCo}}_{2}{\mathrm{As}}_{2}$, which standard structure techniques predict...
We have obtained the equilibrium volumes, bulk moduli, and equations of state ferromagnetic cubic $\ensuremath{\alpha}$ paramagnetic hexagonal $\ensuremath{\epsilon}$ phases iron in close agreement with experiment using an ab initio dynamical mean-field-theory approach. The local correlations are shown to be crucial for a successful description ground-state properties $\ensuremath{\epsilon}$-Fe. Moreover, they enhance effective mass quasiparticles reduce their lifetimes across...
Motivated by the recent experimental report of a possible light-induced superconductivity in ${\mathrm{K}}_{3}{\mathrm{C}}_{60}$ at high temperature [Mitrano et al., Nature 530, 451 (2016)], we investigate theoretical mechanisms for enhanced ${A}_{3}{\mathrm{C}}_{60}$ fullerenes. We find that an ``interaction imbalance'' corresponding to smaller value Coulomb matrix element two molecular orbitals comparison third one, efficiently enhances superconductivity. Furthermore, perform...
We introduce and compare three different Monte Carlo determinantal algorithms that allow one to compute dynamical quantities, such as the self-energy, of fermionic systems in their thermodynamic limit. show most efficient approach expresses sum a factorial number one-particle-irreducible diagrams recursive determinants with exponential complexity. By comparing results for two-dimensional Hubbard model those obtained from state-of-the-art diagrammatic Carlo, we can reach higher perturbation...
We introduce a spin-symmetry-broken extension of the connected determinant algorithm [Riccardo Rossi, Determinant diagrammatic Monte Carlo in thermodynamic limit, Phys. Rev. Lett. 119, 045701 (2017).]. The resulting systematic perturbative expansions around an antiferromagnetic state allow for numerically exact calculations directly inside magnetically ordered phase. show new precise results magnetic phase diagram and thermodynamics three-dimensional cubic Hubbard model at half-filling. With...