Banca de DEFESA: LUCAS RODRIGUES DELGADO DE FREITAS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUCAS RODRIGUES DELGADO DE FREITAS
DATE: 07/11/2024
TIME: 08:30
LOCAL: Plataforma Google Meet
TITLE:

Majorana mean-field theory with Z2 vortices: electrical tests in the extended Kitaev model

KEY WORDS:

Quantum matter, topological quantum computation, mean-field theory, Majorana fermions.

PAGES: 145
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

The Kitaev honeycomb model realizes a quantum spin liquid where spin degrees of freedom are fractionalized into itinerant
Majorana fermions and localized vortices. The entanglement among these particles holds promise for executing fault-tolerant
topological quantum computation. While several materials have been proposed to host a quantum spin liquid phase, concrete
evidence confirming its existence remains elusive. To aid in identifying this phase, we propose an electrical test using the
charge profile, offering a signature for the Z2 vortices in Kitaev materials.
This study explores the electric charge response in Kitaev materials, considering a generalized spin model including
Heisenberg, off-diagonal exchange interactions, and magnetic Zeeman field. Majorana mean-field theory is employed to
analyze spin correlations around vortices, revealing spatial anisotropy in the charge distribution, quantified by the electric
quadrupole moment. This mean-field approach remains exact in the pure Kitaev limit and captures the fundamental physics
across the Kitaev spin liquid phase. The quadrupole-quadrupole interaction between distant vortices is shown to be either
repulsive or attractive, depending on the parameters. We predict that electrically biased scanning probe tips can help create
vortices at predetermined locations.
The findings of our study pave the way for electrically manipulating Ising anyons in Kitaev spin liquids, offering a promising
path for technological applications of Kitaev materials.

COMMITTEE MEMBERS:
Interno - 1519258 - DORY HELIO AIRES DE LIMA ANSELMO
Externo à Instituição - EDSON VERNEK - UFU
Externo à Instituição - ERIC DE CASTRO E ANDRADE - USP
Interno - 2411793 - LEONARDO DANTAS MACHADO
Presidente - 1313663 - RODRIGO GONCALVES PEREIRA