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| Main Authors: | , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2506.14326 |
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| _version_ | 1866912435929088000 |
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| author | Poghosyan, Hasmik Poghossian, Rubik |
| author_facet | Poghosyan, Hasmik Poghossian, Rubik |
| contents | In this paper we investigate 5-point Liouville conformal block with a level 2 degenerate field insertion. Our main tool is the BPZ differential equation, which, upon placing three of the insertions at the standard positions $\infty$, $1$, and $0$, reduces to a linear differential equation which is of order two in the degenerate insertion point $z$, and order one in the remaining point $x$. In a previous paper, it was conjectured that the solution could be expressed in terms of a single hypergeometric function and its derivative, with coefficients computable via recursive relations up to the desired order $x^k$. In this paper, we simplify these recursion relations and provide a rigorous inductive proof of the conjecture.
Our representation of the 5-point conformal block readily facilitates the connection between various analyticity regions through classical connection formulae for the hypergeometric function.
In the quasi-classical limit, the 5-point BPZ equation reduces to the Heun equation. Consequently, we recover a recently proposed representation of the Heun equation in terms of a single hypergeometric function, which has proven to be highly effective in the analysis of gravitational perturbation of black holes. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_14326 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Exact expressions for the 5-Point Liouville conformal block with a level-two degenerate field insertion Poghosyan, Hasmik Poghossian, Rubik High Energy Physics - Theory In this paper we investigate 5-point Liouville conformal block with a level 2 degenerate field insertion. Our main tool is the BPZ differential equation, which, upon placing three of the insertions at the standard positions $\infty$, $1$, and $0$, reduces to a linear differential equation which is of order two in the degenerate insertion point $z$, and order one in the remaining point $x$. In a previous paper, it was conjectured that the solution could be expressed in terms of a single hypergeometric function and its derivative, with coefficients computable via recursive relations up to the desired order $x^k$. In this paper, we simplify these recursion relations and provide a rigorous inductive proof of the conjecture. Our representation of the 5-point conformal block readily facilitates the connection between various analyticity regions through classical connection formulae for the hypergeometric function. In the quasi-classical limit, the 5-point BPZ equation reduces to the Heun equation. Consequently, we recover a recently proposed representation of the Heun equation in terms of a single hypergeometric function, which has proven to be highly effective in the analysis of gravitational perturbation of black holes. |
| title | Exact expressions for the 5-Point Liouville conformal block with a level-two degenerate field insertion |
| topic | High Energy Physics - Theory |
| url | https://arxiv.org/abs/2506.14326 |