# Controllable Quantum Switchboard

## TL;DR

This paper introduces a quantum switchboard capable of functioning as both an optimal quantum cloning machine and a quantum demultiplexer, utilizing a specially prepared four-qubit entangled state.

## Contribution

It presents a novel quantum switchboard design that combines cloning and demultiplexing functionalities within a single four-qubit entangled state.

## Key findings

- Demonstrates the switchboard's ability to clone quantum states optimally.
- Shows the switchboard can effectively demultiplex quantum information.
- Highlights the role of four-qubit entanglement in versatile quantum information processing.

## Abstract

All quantum information processes inevitably requires the explicit state preparation of an entangled state. Here we present the construction of a quantum switchboard which can act both as an optimal quantum cloning machine and a quantum demultiplexer based on the preparation of a four-qubit state.