A new age of innovation is being heralded by scientists increasing mastery of quantum mechanics. There is enormous potential in technologies that harness the power of nature, from computers that are more powerful than today's leading systems, to sensors that can detect dark matter, and a quantum internet.
The first ever Bell state analyzer for frequency bin coding was designed and demonstrated by researchers at the Oak Ridge National Laboratory.
Their findings were published.
Before information can be sent over a quantum network, it needs to be in a quantum state. This information is contained in qubits, or the quantum version of classical computing, used to store information that becomes entangled, meaning they cannot be described independently of one another.
When the qubits are said to be in, theanglement is maximized.
Many of the protocols needed to perform quantum communication and distribute entanglement across a quantum network are measured. The first Bell state analyzer developed specifically for frequency bin coding, a quantum communications method that harnesses single photons residing in two different frequencies simultaneously, was developed by the team.
A Bell state analyzer is needed to achieve things such as teleportation.
The act of sending information from one party to another across a significant physical distance and the ability to entangle previously unentangled qubit pairs are both referred to as entangle swap.
Two quantum computers can be connected through a fiber-optic network, but they cannot interact with each other on their own.
They can be entangled with a single photon. The two quantum computers are now entangled even though they never interacted, because of the way these two photons were sent down optical fiber. This is a critical capability for building complex quantum networks.
The analyzer can only distinguish between two Bell states at any given time. Measuring the other two states would require a lot of complexity that is unnecessary.
The analyzer was designed with simulations and has shown 98% fidelity, but the two percent error rate is the result of unavoidable noise from the random preparation of the test photons, not the analyzer itself. This incredible accuracy enables the fundamental communication protocols necessary for frequency bins.
The fall of 2020 saw the first demonstration of single Frequency-bin qubits being fully controlled as needed to transfer information over a quantum network.
Researchers at ORNL demonstrated quantum gates, or logical operations necessary for performing quantum communications protocols, using a technology developed at ORNL. In these protocols, researchers need to be able to manipulate photons in a user-defined way, often in response to measurements performed on particles elsewhere in the network.
The traditional operations used in classical computers and communications technologies, such as AND/OR, operate on digital zeros and ones individually, whereas quantum gates operate on simultaneous superpositions of zeros and ones, keeping the quantum information protected as it passes through, a phenomenon required to realize true quantum
It has traditionally been difficult to perform data manipulation and processing operations using frequencies that are compatible with fiber optics.
With the completion of the Bell state analyzer, Lukens and colleagues are looking to expand to a complete entanglement swap experiment, which would be the first of its kind. This work is planned as part of ORNL's Quantum-Accelerated Internet Testbed project.
More information: Navin B. Lingaraju et al, Bell state analyzer for spectrally distinct photons, Optica (2022). DOI: 10.1364/OPTICA.443302 Journal information: Optica Citation: Giant leap toward quantum internet realized with Bell state analyzer (2022, March 4) retrieved 4 March 2022 from https://phys.org/news/2022-03-giant-quantum-internet-bell-state.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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