Quantum Effects in the Interference of Light

L. Mandeļ

Peyman Azodi, HERSCHEL A. RABITZ

Despite extensive research on long-range interacting quantum systems, the physical mechanism responsible for the emergence of light cones remains unidentified. This work presents a novel perspective on the origins of locality and emergent light cones in quantum systems with long-range interactions. We identify a mechanism in such spin chains where effective entanglement light cones emerge due to destructive interference among quantum effects that entangle spins. Although long-range entangling effects reach beyond the identified light cone, due to destructive interference, entanglement remains exponentially suppressed in that region, ultimately leading to the formation of the light cone. We demonstrate that this interference not only drives but is also necessary for the emergence of light cones. Furthermore, our analysis reveals that reducing the interaction range weakens this interference, surprisingly increasing the speed of entanglement transport, an effect that opens new experimental opportunities for investigation.

GREGORY A. BREIT

P. R. Berman

Stefano Longhi

A quantum theory of light propagation in two optical channel waveguides tunneling coupled to a common continuum of modes (such as those of a slab waveguide) is presented, and classical and quantum interference effects are investigated. For classical light, the photonic system realizes an optical analog of coherent population trapping in the continuum encountered in atomic physics, where destructive interference between different light leakage channels leads to the appearance of a trapped state embedded in the continuum. For nonclassical light, two-photon interference effects are predicted, such as the tendency of photon pairs to bunch when decaying into the continuum.

Anton N. Vetlugin, Ruixiang Guo, Giorgio Adamo +2 more

Dissipation was traditionally considered as a destructive effect for quantum phenomena such as quantum light interference. In spite of this, correctly designed dissipation may provide an additional degree of freedom for quantum light control. Here we investigate, both theoretically and experimentally, different aspects of coherent quantum light interaction with lossy beamsplitters. Applications of dissipative interference for quantum technology are discussed.