# Quantum Renyi relative entropies on a spin chain with interface defects

## TL;DR

This paper calculates quantum Renyi relative entropies in an infinite spinless fermionic chain with a defect, revealing their dependence on the effective central charge and providing explicit formulas for quantum fidelity and relative entropy.

## Contribution

It introduces explicit analytic expressions for quantum Renyi relative entropies in a defected spin chain, linking them to the effective central charge.

## Key findings

- Quantum Renyi relative entropies depend non trivially on the effective central charge.
- Explicit formulas for quantum fidelity and relative entropy are derived.
- Numerical analysis confirms the theoretical dependence on the central charge.

## Abstract

We compute the quantum Renyi relative entropies in an infinite spinless fermionic chain with a defect. Doing a numerical analysis we will show that the resulting quantity depends non trivially on the effective central charge of the theory. Moreover, we will see that an explicit analytic expression can be written for all of them and from that, one can read the quantum fidelity and the relative entropy.