# Heralded Channel Holevo Superadditivity Bounds from Entanglement Monogamy

## TL;DR

This paper demonstrates how monogamy of squashed entanglement constrains the superadditivity of Holevo capacity in heralded quantum channels, with implications for quantum erasure channels, experimental loss, and quantum games.

## Contribution

It introduces heralded channels and applies entanglement monogamy to bound superadditivity of Holevo capacity, extending to quantum games and multi-party entanglement measures.

## Key findings

- Monogamy of squashed entanglement limits Holevo superadditivity in heralded channels.
- Heralded channels model quantum erasure with arbitrary channels and experimental loss.
- Entanglement monogamy bounds non-classicality and entanglement-dependent quantities in multi-party scenarios.

## Abstract

We show that for a particular class of quantum channels, which we call heralded channels, monogamy of squashed entanglement limits the superadditivity of Holevo capacity. Heralded channels provide a means to understand the quantum erasure channel composed with an arbitrary other quantum channel, as well as common situations in experimental quantum information that involve frequent loss of qubits or failure of trials. We also show how entanglement monogamy applies to non-classicality in quantum games, and we consider how faithful, monogamous entanglement measures may bound other entanglement-dependent quantities in many-party scenarios.