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"Weighing" a closed system and the time-energy uncertainty principle
1School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel and Department of Physics, University of South Carolina, Columbia, South Carolina 29208, USA.
Physical Review Letters
|October 4, 2000
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 tau, required to measure the total energy with accuracy DeltaE, is bounded according to tauDeltaE>Planck's over 2pi. 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.