  In this paper, a protocol is proposed in which energy extraction from local
vacuum states is possible by using quantum measurement information for the
vacuum state of quantum fields. In the protocol, Alice, who stays at a spatial
point, excites the ground state of the fields by a local measurement.
Consequently, wavepackects generated by A' measurement propagate the vacuum to
spatial infinity. Let us assume that Bob stays away from Alice and fails to
catch the excitation energy when the wavepackets pass in front of him. Next
Alice announces her local measurement result to Bob by classical communication.
Bob performs a local unitary operation depending on the measurement result. In
this process, positive energy is released from the fields to Bob's apparatus of
the unitary operation. In the field systems, wavepackets are generated with
negative energy around Bob's location. Soon afterwards, the negative -energy
wavepackets begin to chase after the positive-energy wavepackets generated by
Alice and form loosely bound states.
