5,927 research outputs found
Quantum clocks observe classical and quantum time dilation
At the intersection of quantum theory and relativity lies the possibility of
a clock experiencing a superposition of proper times. We consider quantum
clocks constructed from the internal degrees of relativistic particles that
move through curved spacetime. The probability that one clock reads a given
proper time conditioned on another clock reading a different proper time is
derived. From this conditional probability distribution, it is shown that when
the center-of-mass of these clocks move in localized momentum wave packets they
observe classical time dilation. We then illustrate a quantum correction to the
time dilation observed by a clock moving in a superposition of localized
momentum wave packets that has the potential to be observed in experiment. The
Helstrom-Holevo lower bound is used to derive a proper time-energy/mass
uncertainty relation.Comment: Updated to match published versio
Communication between inertial observers with partially correlated reference frames
In quantum communication protocols the existence of a shared reference frame
between two spatially separated parties is normally presumed. However, in many
practical situations we are faced with the problem of misaligned reference
frames. In this paper, we study communication between two inertial observers
who have partial knowledge about the Lorentz transformation that relates their
frames of reference. Since every Lorentz transformation can be decomposed into
a pure boost followed by a rotation, we begin by analysing the effects on
communication when the parties have partial knowledge about the transformation
relating their frames, when the transformation is either a rotation or pure
boost. This then enables us to investigate how the efficiency of communication
is affected due to partially correlated inertial reference frames related by an
arbitrary Lorentz transformation. Furthermore, we show how the results of
previous studies where reference frames are completely uncorrelated are
recovered from our results in appropriate limits.Comment: 9 pages, 3 figures, typos corrected, figures update
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