Abstract
A gedanken experiment is proposed for “weighing” the total mass of a closed system from within the system. We prove that for an internal observer the time , required to measure the total energy with accuracy , is bounded according to . This time-energy uncertainty principle for a closed system follows from the measurement backreaction on the system. We generally examine what other conserved observables are in principle measurable within a closed system and what are the corresponding uncertainty relations.
- Received 10 June 1999
DOI:https://doi.org/10.1103/PhysRevLett.84.1368
©2000 American Physical Society