arXiv subjects

Takumi Oikawa

Publications and source records attributed to Takumi Oikawa.

4 recordsLinked to original sources

arXiv2026

Error-correcting codes over the Mordell-Weil groups of extremal rational elliptic surfaces and the $E_8$ lattice

We construct the $E_8$ lattice from classical error-correcting codes over the Mordell-Weil groups of rational elliptic surfaces that have a singularity lattice of rank 8 (maximal) for all cases of Oguiso-Shioda's classification. By the structure theorem of the Mordell-Weil lattice of rational elliptic surfaces, if the rank of the singularity lattice is maximal, then the Mordell-Weil group is a cyclic group or a direct sum of them. The singularity lattices are glued together by a code over their natural ring to form the $E_8$ lattice. Such constructions of the $E_8$ lattice from codes can be seen as a Lie algebraic extension and further generalization of known code lattice constructions such as Construction A and Construction A${}_{\rm C}$.

hep-th↗

arXiv2026

Error correcting codes and heterotic Narain CFTs

We study error correcting codes that construct the Narain lattices of heterotic strings as code lattices. We identify, in both $E_8\times E_8$ and Spin$(32)/Z_2$ heterotic strings, a pair of a binary code and a set of the corresponding metric, B field, and background gauge field, such that the lattice constructed from the binary code by Construction A coincides with the Narain lattice. We also construct heterotic Narain lattices using codes over $F_3$ and $F_5$ by Construction A${}_C$ and "Construction A${}_g$" with $g=SU(5)$, respectively. As a bi-product, we also clarify the relationship between codes that construct Euclidean even self-dual lattices and NSR-fermions, where the $Z_2$ inversion structure of the generator matrices plays a significant role.

hep-th↗

arXiv2025

Unifying error-correcting code/Narain CFT correspondences via lattices over integers of cyclotomic fields

We identify Narain conformal field theories (CFTs) that correspond to code lattices for quantum error-correcting codes (QECC) over integers of cyclotomic fields $Q(ζ_p)$ $(ζ_p=e^{\frac{2πi}p})$ for general prime $p\geq 3$. This code-lattice construction is a generalization of more familiar ones such as Construction A${}_C$ for ternary codes and (after the generalization stated below) Construction A for binary codes, containing them as special cases. This code-lattice construction is redescribed in terms of root and weight lattices of Lie algebras, which allows to construct lattices for codes over rings $Z_q$ with non-prime $q$. Corresponding Narain CFTs are found for codes embedded into quotient rings of root and weight lattices of $ADE$ series, except $E_8$ and $D_k$ with $k$ even. In a sense, this provides a unified description of the relationship between various QECCs over $F_p$ (or $Z_q$) and Narain CFTs. A further extension on constructing the $E_8$ lattice from codes over the Mordell-Weil groups of extremal rational elliptic surfaces is also briefly discussed.

hep-th↗

arXiv2022

More on Seiberg-Witten Theory and Monstrous Moonshine

We continue the study of a relationship between the instanton expansion of the Seiberg-Witten (SW) prepotential of $D = 4$, ${\cal N }= 2$ $SU(2)$ SUSY gauge theory and the monstrous moonshine. Extending the previous results, we show for the cases of $N_f=2$ and $3$ that $q=e^{2πiτ}$, where $τ$ is the complex gauge coupling, again has an expansion whose coefficients are all integer-coefficient polynomials of the moonshine coefficients of the modular $j$-function in terms of an appropriate expansion variable. We also demonstrate that the new method of calculating the SW prepotential developed here is useful by performing some explicit computations.

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