Quantum Cryptography Below Lake Geneva

Wc i i i l i o d i ~ i x ~ tlir c:nnwp~ or quat~t i i in I)roccssitig loc~isaing on ol)l,i(:al i i t i ~ ) l i ~ i i i i ~ i i t ~ i t i ( i t i . ] l i t \ rLri' i~urodwl i t i ~ ~ ! ~ ~ ~ ~ r ~ ~ i i i e t r ~ ~ ~ i l I y i ts i i ig I IIV r&itivv IJII:ISC or ~~olarisatioii or siiigle pliot~i i is. As w r ar t ' ilcali~ig wit11 qiiaiitiiiii objwlk wv sec that the ( i i t~ tn t~ im bit (qiibil.)is (~slc~nilcd from the clasiral bit as it can he propared i n a sup~!rposition state of two urtliogoiial prop erties (polarisations lor exaniplc). I < a n h i r~r~rriber generation is also quitc: a riatural for a quantum processor, optics requires a siniplc 50/50 beamsplitter with outputs labellcd