  When a measurement is carried out on one of the entangled parties, the second
party can extract work owing to the reduction in its entropy. Here we inquire
the amount of work/energy corresponding to the symmetrization entanglement of
identical particles (bosons) in a condensate. One measures the quantum state of
a particular boson which can be performed only under some certain conditions.
We learn that the extracted work comes out to be the \textit{complete}
thermodynamical energy present in the condensate. %We learn that the work
extracted by the remaining part of the condensate is equal to the excitation
energy of the measured boson times the thermodynamical probability of being in
the excited state, i.e., $\hbar \omega_{eg} \times \exp(-\hbar
\omega_{eg}/k_BT)$. We study the phenomenon in an interacting Bose-Einstein
condensate. Then, we discuss that the results may also have fundamental
implications on the pair creation in QED vacuum.
