Abstract
A theory of spontaneous parametric down-conversion, which gives rise to a quantum state that is entangled in multiple parameters, such as three-dimensional wave vector and polarization, allows us to understand the unusual characteristics of fourth-order quantum interference in many experiments, including ultrafast type-II parametric down-conversion, the specific example illustrated in this paper. The comprehensive approach provided here permits the engineering of quantum states suitable for quantum-information schemes and quantum technologies.
- Received 14 August 2001
DOI:https://doi.org/10.1103/PhysRevA.65.023808
©2002 American Physical Society
