Banca de DEFESA: FABRIZIO GIOVANNI OLIVIERO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : FABRIZIO GIOVANNI OLIVIERO
DATE: 25/04/2024
TIME: 14:00
LOCAL: Auditório do CCET
TITLE:

Majorana Fermi surface state in a network of quantum spin chains

KEY WORDS:

Quantum spin liquids, network construction, spin chains, chiral, gapless, honeycomb, Fermi surface, Majoranas.

PAGES: 67
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

Half a century ago, Anderson’s resonating valence bond theory initiated a compelling research subject in condensed matter
physics: the exploration of the nature of quantum spin liquids. Today, the understanding of these phases of matter is deeply
connected to the concept of quantum entanglement. In a broad context, quantum spin liquids refer to systems wherein the
effective degrees of freedom are described by local magnetic moments residing on the lattice, exhibiting an absence of long-
range order even at very low temperatures. In addition, the ground-state wave function displays significant entanglement, and
excitations manifest fractionalization. In particular, this thesis is focused on the study of the chiral spin liquids that can be
found in Mott insulators that break time-reversal and parity symmetry. Starting from junctions composed of critical spin-1
chains, we construct a honeycomb network hosting a chiral spin liquid with gapless spectrum. The low-energy modes are
characterized by spin-1 Majorana fermions, which give rise to a legitimate two-dimensional state that harbors a Fermi
surface when the interactions at the junctions are adjusted close to chiral fixed points with staggered chirality. We explore the
physical properties and stability of the chiral spin liquid phase against boundary perturbations, employing well-controlled
analytical methods within the effective field theory of the network. Additionally, we establish evident connections with the
excitation spectrum derived from parton constructions on the kagome lattice.

COMMITTEE MEMBERS:
Externo à Instituição - FERNANDO IEMINI DE REZENDE AGUIAR - UFF
Interno - ***.839.841-** - DMITRY MELNIKOV - UFRN
Externo à Instituição - PEDRO ROGÉRIO SÉRGI GOMES - UEL
Interno - 1328776 - RAFAEL CHAVES SOUTO ARAUJO
Presidente - 1313663 - RODRIGO GONCALVES PEREIRA