Quantum entanglement, where particles are coupled together so that the state of one particle immediately affects the state of another, has become a cornerstone of modern quantum science. It plays a crucial role in the development of quantum technologies such as quantum computers and cryptographic systems.
The new study focuses on Genuine Multi-Particle Entanglement (GME), which involves the entanglement of three or more particles. A key challenge is that just because correlations are found between all pairs of particles, it does not necessarily mean that the entanglement involves all the internal levels of each particle. To address this, the researchers introduced the concept of ‘dimensionality’ into the GME, which refers to the number of possible levels (or ‘colours’ in a simplified analogy) that particles can have.
‘We have developed a new metric called the ‘GME dimension’, which allows us to determine whether the entanglement includes all possible levels or only a subset. This distinction is crucial for the development of quantum technologies,’ says Gabriele Cobucci, a PhD student in mathematical physics and one of the authors of the paper.
The new method has significant implications for the future of quantum technology. High-dimensional GME states are particularly valuable for quantum computers and quantum communications, as they provide benefits such as increased stability and the ability to transmit more information safely.
‘By providing a way to certify the dimensionality of GMEs, we hope to contribute to an extended understanding of quantum entanglement and at the same time pave the way for experimental detection schemes that are realistic for the emerging quantum technologies’, concludes Armin Tavakoli, researcher and senior lecturer at the Department of Physics.