In sci.physics.relativity Schoenfeld wrote:
We fill a box with a radioactive material which randomly emits
radiation. The box has a shutter, which is opened and immediately
thereafter shut by a clock at a precise time, thereby allowing some
radiation to escape. So the time is already known with precision. We
still want to measure the conjugate variable energy precisely. We
measure the energy by weighing the box before and after. The
equivalence between mass and energy from special relativity will allow
us to determine precisely how much energy was left in the box.

This was the experiment proposed by Einstein at the 1930 Solvay
Conference. You knew that, right? So you also knew Bohr's reply,
which analyzed in detail the uncertainty in the "precise time"
caused by the change of the energy of the box and the consequent
gravitational red shift. Bohr's answer is reprinted in _Quantum
Theory and Measurement_, ed. Wheeler and Zurek, p. 32-36.

Steve Carlip

wrote in message
...
This was the experiment proposed by Einstein at the 1930 Solvay
Conference. ... Bohr's answer is reprinted in _Quantum
Theory and Measurement_, ed. Wheeler and Zurek, p. 32-36.


You can find this on the web at

http://www.marxists.org/reference/su...ks/dk/bohr.htm

Tom S.