  Passive states of quantum systems are states from which no system energy can
be extracted by any cyclic (unitary) process. Gibbs states of all temperatures
are passive. Strong local (SL) passive states are defined to allow any general
quantum operation, but the operation is required to be local, being applied
only to a specific subsystem. Any mixture of eigenstates in a system-dependent
neighborhood of a nondegenerate, entangled ground state is found to be SL
passive. In particular, Gibbs states are SL passive with respect to a subsystem
only at or below a critical, system-dependent temperature. SL passivity is
associated in many-body systems with the presence of ground state entanglement
in a way suggestive of collective quantum phenomena such as quantum phase
transitions, superconductivity, and the quantum Hall effect. The presence of SL
passivity is detailed for some simple spin systems where it is found that SL
passivity is neither confined to systems of just a few particles nor limited to
the near vicinity of the ground state.
