▁equation , ▁is ▁an ▁equation ▁in ▁statistical ▁mechan ics ▁that ▁rel ates ▁the ▁work ▁done ▁on ▁a ▁system ▁during ▁a ▁non - equ ilib rium ▁transformation ▁to ▁the ▁free ▁energy ▁difference ▁between ▁the ▁final ▁and ▁the ▁initial ▁state ▁of ▁the ▁transformation . ▁During ▁the ▁non - equ ilib rium ▁transformation ▁the ▁system ▁is ▁at ▁constant ▁volume ▁and ▁in ▁contact ▁with ▁a ▁heat ▁res er voir . ▁The ▁C FT ▁is ▁named ▁after ▁the ▁chem ist ▁G av in ▁E . ▁Cro oks ▁( then ▁at ▁University ▁of ▁California ) ▁who ▁discovered ▁it ▁in ▁ 1 9 9 8 . ▁ ▁The ▁most ▁general ▁statement ▁of ▁the ▁C FT ▁rel ates ▁the ▁probability ▁of ▁a ▁space - time ▁traject ory ▁ ▁to ▁the ▁time - re vers al ▁of ▁the ▁traject ory ▁. ▁The ▁theorem ▁says ▁if ▁the ▁dynamics ▁of ▁the ▁system ▁satisfies ▁micro scop ic ▁revers ibility , ▁then ▁the ▁forward ▁time ▁traject ory ▁is ▁expon entially ▁more ▁likely ▁than ▁the ▁reverse , ▁given ▁that ▁it ▁produces ▁entropy , ▁▁▁▁ ▁If ▁one ▁defines ▁a ▁generic ▁reaction ▁coordinate ▁of ▁the ▁system ▁as ▁a ▁function ▁of ▁the ▁Cart esian ▁coordinates ▁of ▁the ▁constitu ent ▁particles ▁( ▁e . g . ▁, ▁a ▁distance ▁between ▁two ▁particles ), ▁one ▁can ▁character ize ▁every ▁point ▁along ▁the ▁reaction ▁coordinate ▁path ▁by ▁a ▁parameter ▁, ▁such ▁that ▁ ▁and ▁ ▁correspond ▁to ▁two ▁ens emb les ▁of ▁ ▁micro states ▁for ▁which ▁the ▁reaction ▁coordinate ▁is ▁const rained ▁to ▁different ▁values . ▁A ▁dynam ical ▁process ▁where ▁