1,624 research outputs found
Entangled Quantum Clocks for Measuring Proper-Time Difference
We report that entangled pairs of quantum clocks (non-degenerate quantum
bits) can be used as a specialized detector for precisely measuring difference
of proper-times that each constituent quantum clock experiences. We describe
why the proposed scheme would be more precise in the measurement of proper-time
difference than a scheme of two-separate-quantum-clocks. We consider
possibilities that the proposed scheme can be used in precision test of the
relativity theory.Comment: no correction, 4 pages, RevTe
Single electron relativistic clock interferometer
Although time is one of the fundamental notions in physics, it does not have
a unique description. In quantum theory time is a parameter ordering the
succession of the probability amplitudes of a quantum system, while according
to relativity theory each system experiences in general a different proper
time, depending on the system's world line, due to time to time dilation. It is
therefore of fundamental interest to test the notion of time in the regime
where both quantum and relativistic effects play a role, for example, when
different amplitudes of a single quantum clock experience different magnitudes
of time dilation. Here we propose a realization of such an experiment with a
single electron in a Penning trap. The clock can be implemented in the
electronic spin precession and its time dilation then depends on the radial
(cyclotron) state of the electron. We show that coherent manipulation and
detection of the electron can be achieved already with present day technology.
A single electron in a Penning trap is a technologically ready platform where
the notion of time can be probed in a hitherto untested regime, where it
requires a relativistic as well as quantum description.Comment: 9 pages, 4 figure
General relativistic effects in quantum interference of photons
Quantum mechanics and general relativity have been extensively and
independently confirmed in many experiments. However, the interplay of the two
theories has never been tested: all experiments that measured the influence of
gravity on quantum systems are consistent with non-relativistic, Newtonian
gravity. On the other hand, all tests of general relativity can be described
within the framework of classical physics. Here we discuss a quantum
interference experiment with single photons that can probe quantum mechanics in
curved space-time. We consider a single photon travelling in superposition
along two paths in an interferometer, with each arm experiencing a different
gravitational time dilation. If the difference in the time dilations is
comparable with the photon's coherence time, the visibility of the quantum
interference is predicted to drop, while for shorter time dilations the effect
of gravity will result only in a relative phase shift between the two arms. We
discuss what aspects of the interplay between quantum mechanics and general
relativity are probed in such experiments and analyze the experimental
feasibility.Comment: 16 pages, new appendix, published versio
Nonlocal Aspects of a Quantum Wave
Various aspects of nonlocality of a quantum wave are discussed. In
particular, the question of the possibility of extracting information about the
relative phase in a quantum wave is analyzed. It is argued that there is a
profound difference in the nonlocal properties of the quantum wave between
fermion and boson particles. The phase of the boson quantum state can be found
from correlations between results of measurements in separate regions. These
correlations are identical to the Einstein-Podolsky-Rosen (EPR) correlations
between two entangled systems. An ensemble of results of measurements performed
on fermion quantum waves does not exhibit the EPR correlations and the relative
phase of fermion quantum waves cannot be found from these results. The
existence of a physical variable (the relative phase) which cannot be measured
locally is the nonlocality aspect of the quantum wave of a fermion.Comment: 12 page
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