This year we give thanks for an idea that establishes a direct connection between the concepts of “energy” and “information”: Landauer’s Principle. ...Okay, fine, but various big-shot physicists foolishly insist that information is always preserved. They have to deny information loss in order to argue for many-worlds (MWI) and black hole firewalls.
Landauer’s Principle states that irreversible loss of information — whether it’s erasing a notebook or swiping a computer disk — is necessarily accompanied by an increase in entropy. Charles Bennett puts it in relatively precise terms:Any logically irreversible manipulation of information, such as the erasure of a bit or the merging of two computation paths, must be accompanied by a corresponding entropy increase in non-information bearing degrees of freedom of the information processing apparatus or its environment.The principle captures the broad idea that “information is physical.”
Monday, December 2, 2013
Irreversible loss of information
Physicist Sean M. Carroll writes: