In the pursuit of photonic quantum technology, previous studies have confirmed the usefulness of Fokker states. These multiphoton, multimodal states are achieved by skillfully combining multiple single-photon inputs using so-called linear optics.
However, some important and valuable quantum states require more than just this photon-by-photon approach.
Now, a team of researchers from Kyoto University and Hiroshima University has theoretically and experimentally confirmed the unique advantages of non-Fokk states (or INFS), complex quantum states that require multiple photon sources and linear optics. The study was published in the journal Science Advances.
We successfully confirmed the existence of INFS using multiphoton optical quantum circuits," said Shigeki Takeuchi, corresponding author at the Graduate School of Engineering.
Our research will lead to breakthroughs in applications such as optical quantum computers and optical quantum sensing," added co-author Geobae Park.
Photons are a promising carrier because they can be transmitted over long distances while maintaining their quantum state at a constant room temperature. Utilizing many photons in multiple modes will enable long-range optical quantum cryptography, optical quantum sensing, and optical quantum computing.
We painstakingly used our Fourier transform photon quantum circuit to manifest two photons in three different paths, painstakingly generating a complex type of INFS, which is the most challenging phenomenon in achieving conditional coherence," explains co-author Ryo Okamoto.
I'm a tech creator In addition, this study compares another phenomenon to the widespread application of quantum entanglement, which appears and disappears only by passing through a single linear optical element. Quantum entanglement is a quantum state in which two or more correlated states are superimposed between two independent systems. "Surprisingly, this study shows that the INFS properties do not change as they pass through a network of many linear optical elements, which marks a leap forward in optical quantum technology," notes Holge, co-author at Hiroshima University.
Takeuchi's team argues that INFS exhibits conditional coherence, a somewhat mysterious phenomenon where even the detection of one photon means that there are remaining photons in the superposition of multiple paths.
"Our next phase is to realize larger-scale multiphoton, multimodal, and optical quantum circuit chips," Tayuchi announced. ”