Entanglement-assisted quantum communication with simple measurements
The quantum information and quantum optics group at Stockholm University led by Professor Mohamed Bourennane has realized a novel entanglement assisted quantum communication with simple measurements. The result has been published in Nature Communication.
Dense coding is the paradigmatic protocol, taught in nearly every introductory course to quantum information theory, that reveals the power of entanglement in quantum communications. Its discovery, about 30 years ago, showcased that entanglement may boost the transmission of information over a quantum channel and it motivated a research program focused on the advantages of entanglement in information transmission.
Remarkably, however, little is known about the role of entanglement beyond the specific task of information transfer. Given the fact that both entanglement and quantum communication have separately been subject to intensive research in the past decades, it is indeed surprising that the most powerful resource of quantum theory, namely the combination of entanglement and quantum communication, remains largely an uncharted territory beyond the shining example of dense coding.
With our work, we take the initiative to explore the role of entanglement in quantum communications in physical scenarios that are more general than that of reliably encoding and decoding classical information. These more general scenarios correspond, for example, to the total information of a sender being divided into several pieces which are individually accessed by the receiver (e.g., the yellow pages). We then pose a simple, yet natural, motivating question: does dense coding account for the most general predictions of quantum theory? While the answer is long known to be positive for the specific task of information transfer, we show that, in general, the answer is negative. We show this by identifying a simple communication task in which the same quantum resources used in dense coding can be used more effectively using an entirely different quantum protocol. These more general protocols are more tolerant to noise than dense coding, can be implemented using seminal measurements in quantum entanglement swapping and are within reach of modern experimental capabilities. We demonstrate their practicality in a photonics realization in which we outperform the limitations of quantum dense coding using the same elementary resources.
Our findings demonstrate that the power of entanglement in communication experiments is not fully captured by its ability to boost channel capacities. On the theoretical side, it provides the key motivation for a systematic investigation of the topic beyond dense coding. On the experimental side, it shows that more general and more powerful protocols than dense coding can be efficiently implemented in the most relevant platform.
This work is performed in collaboration with Hitachi Energy Research, Västerås, Sweden and theory colleagues Dr Armin Tavakoli from Technical University of Vienna and Jef Pauwels from Université libre de Bruxelles.
- Contact: Amelie Piveteau: firstname.lastname@example.org or Mohamed Bourennane email@example.com.
- Amélie Piveteau, Jef Pauwels, Emil Håkansson, Sadiq Muhammad, Mohamed Bourennane & Armin Tavakoli, Entanglement-assisted quantum communication with simple measurements Nature Communications volume 13, 7878 (2022), https://doi.org/10.1038/s41467-022-33922-5
Last updated: January 17, 2023