### Simplified Discovery in Quantum Entanglement An international team of physicists led by researchers from Nanjing University and the Max Planck Institute for the Science of Light have found a more straightforward method to create quantum entanglement between distant photons. This innovative approach does away with the need for pre-entangled pairs, Bell-state measurements, or the detection of all auxiliary photons. Instead, it utilizes the indistinguishability of photon paths to generate entanglement, challenging traditional views. At the heart of this discovery was the AI tool PyTheus, initially used to replicate established entanglement-swapping protocols. Surprisingly, it unearthed a simpler technique that bypasses the conventional need for starting with entangled pairs and performing joint measurements. As Mario Krenn from the Max Planck Institute comments, the AI repeatedly suggested a solution that was perceived too simple at first but proved valid. Typically, entanglement swapping involves two separate entangled pairs and a Bell-state measurement, but the new method achieves a similar outcome sans these steps.

By ensuring photon paths are identical, the team induced entanglement solely through quantum uncertainty. This revelation, akin to altering nearly 25 years of quantum network design, could simplify quantum communication, making networks easier to construct and scale. Although scaling this method to practical network sizes remains a challenge due to factors like environmental noise and device imperfections, the leap underscores the potential of AI-assisted scientific discovery. Krenn notes that solutions discovered through AI often challenge existing norms and can result in unexpected simplifications. This work suggests that AI can help reshape the quantum computing landscape by exposing simpler, efficiency-boosting protocols. Such AI-driven discoveries not only aid in secure communication but also drive innovations in quantum sensors, simulators, and potentially practical quantum computers. For further technical details, the study can be accessed in Physical Review Letters and on arXiv. The research team included Kai Wang, Zhaohua Hou, Kaiyi Qian, Leizhen Chen, Shining Zhu, and Xiao-Song Ma from Nanjing University's National Laboratory of Solid-state Microstructures.