Anisotropically high entanglement of biphotons
Mikhail Vladimirovich Fedorov, S. P. Kulik, Ekaterina V. Moreva, Stanislav S. Straupe, Pavel A. Volkov, Maxim A. Efremov · 2007
Biphoton states arising in the process of spontaneous parametric down-conversion (SPDC) are entangled with respect to continuous variables, momentum or coordinates. We discuss some novel and unexpected features of biphoton wave packets.