Quantum entanglement refers to a phenomenon in quantum mechanics in which two or more particles become linked such that the state of each particle cannot be described independently of the others, even when they are separated by a large distance. The principle, referred to by Albert Einstein as “spooky action at a distance,” is now utilized in quantum networks to transfer information. The building blocks of these networks—quantum nodes—can generate and measure quantum states.

Among the candidates that can function as quantum nodes, the Sn-V center in diamond (a defect where a tin (Sn) atom replaces a carbon atom, resulting in an interstitial Sn atom between two carbon vacancies) has been shown to have suitable properties for quantum network applications.

The Sn-V center is expected to exhibit a long spin coherence time in the millisecond range at Kelvin temperatures, allowing it to maintain its quantum state for a relatively long period of time. However, these centers have yet to produce photons with similar characteristics, which is a necessary criterion for creating remote entangled quantum states between quantum network nodes.

An international team of scientists claim to have found a way to speed up, slow down, and even reverse the clock of a given system by taking advantage of the unusual properties of the quantum world, Spanish newspaper El País reports.

In a series of six papers, the team from the Austrian Academy of Sciences and the University of Vienna detailed their findings. The familiar laws of physics don’t map intuitively onto the subatomic world, which is made up of quantum particles called qubits that can technically exist in more than one state simultaneously, a phenomenon known as quantum entanglement.

Now, the researchers say they’ve figured out how to turn these quantum particles’ clocks forward and backward.

An Austrian and Spanish team demonstrated that a process can be ‘rewound’ to restore the components of an atom to their previous state.