arXiv subjects

Masayoshi Sato

Publications and source records attributed to Masayoshi Sato.

3 recordsLinked to original sources

arXiv2026

Genus-Two Contributions to Late-Time Correlators in JT Gravity

In this work, we analyze the late-time two-point correlation function in Jackiw--Teitelboim gravity, focusing on the genus-two ($g=2$) contribution associated with two baby universes. Extending the analysis of the single-baby-universe ($g=1$) case, we formulate an amplitude describing the emission and absorption of two baby universes during the evolution of the Hartle--Hawking state. This formulation reduces the problem to a moduli-space integral involving the Weil--Petersson volume $V_{0,3}$. To evaluate this integral, we decompose $V_{0,3}$ into contributions from Kontsevich graphs and extend the no-shortcut condition to the relevant genus-two strip geometries. Combined with the strip approximation, this decomposition reorganizes the moduli-space integral into a finite sum of contributions associated with distinct geometric configurations. We then explicitly evaluate the strip-geometry contributions corresponding to the emission of two baby universes and determine their contribution to the genus-two late-time two-point correlation function. Our results suggest that the strip approximation, together with the no-shortcut condition, provides a useful analytic framework for studying higher-genus geometries containing multiple wormholes.

hep-th↗

arXiv2025

Degenerate chords in double-scaled SYK

The matter operator in the double-scaled SYK model exhibits special properties when its dimension is analytically continued to -1/2. At this dimension, the operator is in a degenerate representation of the q-deformed oscillator algebra and satisfies a null vector equation. Its peculiar fusion property gives rise to recursion relations among matter correlation functions. We find that these relations allow us to determine the two-point function without having to sum over infinitely many chord diagrams.

hep-th↗

arXiv2025

What happens due to the baby universe effect in JT gravity? -Analysis of correlation functions and ERB length at late time using three approaches-

We analyze the correlation function in JT gravity using three approaches: by summing over all geodesics connecting boundary operators, integrating over the region of moduli space determined by the ``no-shortcut condition'' introduced by D.Stanford and Z.Yang, and using the formula for the universal spectral density correlation in the $τ$-scaling limit. We find that the behaviors of the three results coincide at late times: they all exhibit a ``ramp'' instead of permanent decay. Using the third approach we also confirm that the ``plateau'' appears after $T_H=2πe^{S_0}\hatρ_0(E)$. Overall, our results are consistent with the SFF analysis. We also calculate the ERB length $\langle \ell(T) \rangle$ using the three approaches and find that the results are in good agreement with each other. We also find that the $\langle \ell(T) \rangle$ grows as a cubic function in $T$ due to the contribution from geometry including one observable baby universe, and converges to a constant after $T=T_H$. For the geometry with one baby universe, we compute the size $\langle b(T) \rangle$ of the baby universe and find that it is of the same order as $\langle \ell(T) \rangle$. This result is consistent with the baby universe emission mechanism claimed by P.Saad.

hep-th↗