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In this paper, we present generalized edge-pairings for the family of hyperbolic tessellations {4 λ, 4} with the purpose of obtaining the corresponding discrete group of isometries. These tessellations have greater density packing than the self-dual tessellations {4 λ, 4 λ}, implying that the associated codes achieve the least error probability or, equivalently, that these codes are optimum codes. We also consider the topological quantum error-correcting codes on surfaces with genus g ≥ 2, as proposed in other papers. From that, we focus on the class of topological quantum maximum distance separable codes, showing that the only such codes are precisely the ones with minimum distance d ≤ 2.

In the last three decades, several constructions of quantum error-correcting codes were presented in the literature. Among these codes, there are the asymmetric ones, i.e., quantum codes whose $Z$-distance $d_z$ is different from its $X$-distance $d_x$. The topological quantum codes form an important class of quantum codes, where the toric code, introduced by Kitaev, was the first family of this type. After Kitaev's toric code, several authors focused attention on investigating its structure and the constructions of new families of topological quantum codes over Euclidean and hyperbolic surfaces. As a consequence of establishing the existence and the construction of asymmetric topological quantum codes in Theorem \ref{main}, the main result of this paper, we introduce the class of hyperbolic asymmetric codes. Hence, families of Euclidean and hyperbolic asymmetric topological quantum codes are presented. An analysis regarding the asymptotic behavior of their distances $d_x$ and $d_z$ and encoding rates $k/n$ versus the compact orientable surface's genus is provided due to the significant difference between the asymmetric distances $d_x$ and $d_z$ when compared with the corresponding parameters of topological codes generated by other tessellations. This inherent unequal error-protection is associated with the nontrivial homological cycle of the $\{p,q\}$ tessellation and its dual, which may be appropriately explored depending on the application, where $p\neq q$ and $(p-2)(q-2)\ge 4$. Three families of codes derived from the $\{7,3\}$, $\{5,4\}$, and $\{10,5\}$ tessellations are highlighted., Comment: 30 pages

In this paper we present generalized edge-pairings for the family of hyperbolic tessellations $$\{10\lambda ,2\lambda \}$$ , with the purpose to obtain the corresponding discrete group of isometries. These tessellations have greater density packing than the self-dual tessellations $$\{4\lambda ,4\lambda \}$$ implying that the associated codes achieve the least error probability, or equivalently, that these codes are optimum codes.

Orientadores: Reginaldo Palazzo Jr., Mercio Botelho Faria Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação Resumo: Dentro do contexto de projetar sistema de comunicação digital em espaços homogêneos, em particular, em espaços hiperbólicos, é necessário estabelecer um procedimento sistemático para construção de reticulados O, como elemento base para construção de constelações de sinais geometricamente uniformes. E através desse procedimento que identificamos as estruturas algébrica e geométrica além de construir códigos geometricamente uniformes em espaços homogêneos. Propomos, a partir desses reticulados, a construção de grupos fuchsianos aritméticos Tp obtidos de tesselações hiperbólicas {p; q}, derivados de álgebras de divisão dos quaternios A sobre corpos de números K. Generalizamos o processo de identificação desses grupos em ordens dos quatérnios (reticulados hiperbólicos), associadas às constelações de sinais geometricamente uniformes, provenientes de grupos discretos. Esse procedimento permite rotular os sinais das constelações construídas por elementos de uma estrutura algébrica Abstract: Within the context of digital communications system in homogeneous space in particular, in hyperbolic spaces, it is necessary to establish systematic procedure for the construction of lattices O ; as the basic entity for construction of eometrically uniforms signal constellations. By this procedure we identify the algebraic and geometric structures to construct geometrically uniforms codes in homogeneous spaces. We propose, from lattices, the construction of arithmetic fuchsian groups ¡p obtained by hyperbolic tessellations {p; q}, derived from division quaternion algebras A over numbers fields K. We generalize the process of identification of these groups in quaternion orders (hyperbolic lattices), which are associated with geometrically uniforms signal constellations, proceeding from discrete groups. This procedure allows us to realize the labelling of the signals belonging to such constellations by elements of an algebraic structure Doutorado Telecomunicações e Telemática Doutor em Engenharia Elétrica

In this paper we generalize the process of identifying arithmetic Fuchsian groups in a quaternion order over an extension of the rational as shown in [3]. This procedure enable us to construct new lattices in the hyperbolic plane which are associated with signal constellations. In addition to this, the procedure also enable us to realize the labelling of the signals belonging to such signal constellations.