# Broadcasting of correlations via orthogonal & non-orthogonal state dependent cloners

## TL;DR

This paper investigates how different types of state-dependent and state-independent quantum cloners, including orthogonal and non-orthogonal, can be used to broadcast entanglement, highlighting scenarios where state-dependent cloners outperform state-independent ones.

## Contribution

It introduces and analyzes various types of state-dependent quantum cloning machines, deriving conditions for fidelity independence and comparing their effectiveness in entanglement broadcasting.

## Key findings

- State-dependent cloners can outperform state-independent ones in broadcasting entanglement.
- Conditions for fidelity independence in orthogonal and non-orthogonal cloners are derived.
- Broadcasting range depends on input state parameters and cloning type.

## Abstract

In this work, we extensively study the problem of broadcasting of entanglement as state dependent versus state independent cloners. We start by re-conceptualizing the idea of state dependent quantum cloning machine (SD-QCM), and in that process, we introduce different types of SD-QCMs, namely, orthogonal and non-orthogonal cloners. We derive the conditions for which the fidelity of these cloners will become independent of the input state. We note that such a construction allows us to maximize the cloning fidelity at the cost of having partial information of the input state. In the discussion on broadcasting of entanglement, we start with a general two qubit state as our resource and later we consider a specific example of Bell diagonal state. We apply both state dependent and state independent cloners (orthogonal and non-orthogonal), locally and non locally, on input resource state and obtain a range for broadcasting of entanglement in terms of the input state parameters. Our results highlight several instances where the state dependent cloners outperform their state independent counterparts in broadcasting entanglement. Our study provides a comparative perspective on the broadcasting of entanglement via cloning in two qubit scenario, when we have some knowledge of the resource ensemble versus a situation when we have no such information.