Before revision:  In particular, we show that  having access to one extra binary degree of freedom (doubling the  number of states) is sufficient to carry out any P  . Our results provide a novel type of bound on the physical resources needed to perform information processing---the size of a system's  state space.
After revision:  In particular, we show that if there are no constraints on what master equation we can construct, then having access to one extra binary degree of freedom (doubling the number of states) is sufficient to carry out any P . Our results provide a novel type of bound on the physical resources needed to perform information processing---the size of a system's state space.