麻豆淫院

A research team affiliated with UNIST has successfully demonstrated the experimental creation of collective quantum entanglement rooted in dark states鈥攑reviously confined to theoretical models. The findings are published online in .

Unlike bright states, dark states are highly resistant to external disturbances and exhibit remarkably extended lifetimes, making them promising candidates for next-generation quantum technologies such as quantum memory and ultra-sensitive sensors.

Led by Professor Je-Hyung Kim in the Department of 麻豆淫院ics at UNIST, in collaboration with Dr. Changhyoup Lee from the Korea Research Institute of Standards and Science (KRISS) and Dr. Jin Dong Song from the Korea Institute of Science and Technology (KIST), the team has achieved the controlled induction of dark state-based collective entanglement. Remarkably, this entanglement exhibits a lifetime approximately 600 times longer than that of conventional bright states.

Quantum entanglement among multiple indistinguishable particles typically manifests as either bright or dark states. Dark states are characterized by their near-total invisibility to emitted light, allowing the entanglement to persist over extended periods.

While this protective feature holds immense potential for quantum information storage and transmission, creating and maintaining dark states has long posed substantial experimental challenges.

The researchers overcame these obstacles by employing a nanocavity with carefully tuned loss rates, balancing the coupling strength between quantum dots and the cavity's dissipation.

Dr. KyuYoung Kim, the first author of the study, explained, "When the cavity loss is too high, the quantum dots act independently without affecting each other. Conversely, if the coupling is sufficiently strong, a collective entangled state is formed, resistant to external disturbances."

In their experiments, the team observed that the entanglement within the dark state could last up to 36 nanoseconds鈥攁 lifetime approximately 600 times longer than the 62 picoseconds typical of bright states. Additionally, they detected phenomena such as nonclassical photon bunching, providing direct evidence of the dark state's formation.

Although such states usually suppress photon emission, under specific conditions, the entangled quantum dots emitted photons simultaneously, demonstrating the unique properties of the dark state.

Professor Kim remarked, "This experimental realization of dark state entanglement鈥攐nce only theoretical鈥攕hows that by carefully engineering losses, we can preserve quantum correlations over long durations. This opens new avenues for quantum information storage, high-precision sensors, and energy-harvesting technologies based on quantum principles."