University of Chicago Researchers Break New Ground in Quantum Communication

In a significant advancement for quantum technology, researchers at the University of Chicago's Pritzker School of Molecular Engineering have developed a method that could extend quantum communication distances up to 2,000 kilometers, a substantial leap from the previous limit of a few kilometers.

The study, published on November 6, 2025, in Nature Communications, details how the team, led by Assistant Professor Tian Zhong, employed molecular-beam epitaxy to construct rare-earth-doped crystals atom by atom. This technique achieved unprecedented material purity, resulting in quantum coherence times exceeding 10 milliseconds. Such extended coherence times are crucial for maintaining the integrity of quantum information over long distances.

"For the first time, the technology for building a global-scale quantum internet is within reach," Zhong stated. (sciencedaily.com)

Background on Quantum Communication

Quantum communication leverages the principles of quantum mechanics to transmit information securely. A key method in this field is Quantum Key Distribution (QKD), which allows two parties to generate a shared secret key used for encrypting and decrypting messages. The security of QKD is underpinned by the fundamental properties of quantum particles, ensuring that any eavesdropping attempts can be detected.

Historical Context and Previous Records

Prior to this study, significant milestones in quantum communication included:

• 2008: Scientists at the University of Padua detected single photons bounced off a satellite 1,485 km above Earth, marking a critical step toward space-based quantum communication.

• 2015: The National Institute of Standards and Technology (NIST) achieved quantum teleportation over 100 km of optical fiber, demonstrating the feasibility of long-distance quantum communication in fiber-optic lines.

• 2022: Chinese scientists transmitted quantum states between two ground stations over 1,200 km apart via a quantum satellite, advancing the construction of a global quantum information network.

• 2023: Researchers in China set a world record by achieving twin-field QKD through a 1,002-kilometer optical fiber, marking a critical step toward a large-scale quantum network.

• 2025: Chinese scientists transmitted encrypted images over 12,900 km using a microsatellite, setting a new distance record for quantum communication.

Details of the Current Study

The University of Chicago team focused on enhancing the coherence times of quantum systems, a crucial factor for long-distance quantum communication. By utilizing molecular-beam epitaxy, they constructed rare-earth-doped crystals with exceptional purity. This method allowed them to achieve quantum coherence times exceeding 10 milliseconds, a significant improvement over previous materials. The extended coherence time theoretically enables quantum communication over distances up to 2,000 kilometers, surpassing previous limits.

Implications and Future Prospects

This advancement has profound implications for the development of a global quantum internet, offering ultra-secure communication channels immune to conventional hacking methods. The ability to maintain quantum coherence over longer distances could facilitate more robust quantum networks, enhancing secure communications for governments, financial institutions, and other sectors requiring high levels of data security.

The University of Chicago's breakthrough marks a pivotal step toward realizing a global quantum internet, significantly enhancing the feasibility of long-distance quantum communication and its applications in secure data transmission.