Top-level heading

Collective Modes and Correlation Effects in Magnetic Phases of the Hubbard Model

Data e ora inizio evento
Data e ora fine evento
Sede

Dipartimento di Matematica e Fisica, Università di Roma Tre, Via della Vasca Navale 84

Aula esterna
Aula B
Speaker ed affiliazione
Lorenzo del Re
Spontaneous symmetry breaking in interacting fermionic systems leads to a proliferation of independent scattering channels, making the treatment of many-body effects particularly challenging. In this talk, I present two complementary studies addressing the interplay between magnetism, strong correlations, and emergent spectral features in broken symmetry phases of the Hubbard model. First, I introduce an extension of the Two-Particle-Self-Consistent approach (TPSC) to efficiently describe SU(2)-broken magnetic phases. Applied to the antiferromagnetic phase of the Hubbard model, this framework enforces sum rules while preserving Goldstone modes and incorporating vertex corrections. These corrections play a crucial role in renormalizing the Higgs resonance, which we identify as a well-defined excitation in the spin-longitudinal susceptibility. Next, I turn to a variant of the Hubbard model that hosts altermagnetic states—magnetic phases that exhibit Dirac-like band structures. Using a combination of Hartree-Fock and Dynamical Mean Field Theory (DMFT), we show that interaction effects can induce unexpected spectral features, including the re-emergence of Dirac points at high energies near Mott insulating regimes. Additionally, we explore how perturbations can drive topological phase transitions, offering a route to engineer non-trivial electronic states.
Contatti/Organizzatori
pezzini@mat.uniroma1.it