# Exact generalized partition function of 2D CFTs at large central charge

## TL;DR

This paper derives an exact, non-perturbative expression for the generalized partition function of 2D conformal field theories at large central charge, using an auxiliary boson model to incorporate higher qKdV charges.

## Contribution

It introduces a novel auxiliary boson framework that allows expressing the generalized partition function of 2D CFTs at large central charge in closed form.

## Key findings

- Verified the bosonization approach for first seven qKdV charges.
- Derived explicit spectrum of auxiliary bosons from perturbative results.
- Proposed an exact expression for the full spectrum and partition function.

## Abstract

We discuss generalized partition function of 2d CFTs decorated by higher qKdV charges on thermal cylinder. We propose that in the large central charge limit qKdV charges factorize such that generalized partition function can be rewritten in terms of auxiliary non-interacting bosons. The explicit expression for the generalized free energy is readily available in terms of the boson spectrum, which can be deduced from the conventional thermal expectation values of qKdV charges. In other words, the picture of the auxiliary non-interacting bosons allows extending thermal one-point functions to the full non-perturbative generalized partition function. We verify this conjecture for the first seven qKdV charges using recently obtained pertrubative results and find corresponding contributions to the auxiliary boson masses. We further extend these results by conjecturing the full spectrum of bosons and find an exact expression for the generalized partition function as a function of infinite tower of chemical potentials in the limit of large central charge.