"Discovery of Quantum Interference Multiphoton Effect in Light"

Researchers from Leibniz University Hannover and the University of Strathclyde have discovered a new multiphoton effect within the quantum interference of light, disproving previous assumptions about the impact of multiphoton components in interference effects of thermal fields and parametric single photons. The team's research, published in Physical Review Letters, reveals that the interference effect between thermal light and parametric single photons also leads to quantum interference with the background field, challenging previous calculation methods. This discovery could have implications for quantum key distribution and the interpretation of quantum interference effects for secure communications in the future.