9,105 research outputs found
Dynamical resurrection of the visibility in a Mach-Zehnder interferometer
We study a single-electron pulse injected into the chiral edge-state of a
quantum Hall device and subject to a capacitive Coulomb interaction. We find
that the scattered multi-particle state remains unentangled and hence can be
created itself by a suitable classical voltage-pulse . The application of
the inverse pulse corrects for the shake-up due to the interaction and
resurrects the original injected wave packet. We suggest an experiment with an
asymmetric Mach-Zehnder interferometer where the application of such pulses
manifests itself in an improved visibility.Comment: 4 pages, 1 figur
Three-point correlation function of a scalar mixed by an almost smooth random velocity field
We demonstrate that if the exponent that measures non-smoothness of
the velocity field is small then the isotropic zero modes of the scalar's
triple correlation function have the scaling exponents proportional to
. Therefore, zero modes are subleading with respect to the
forced solution that has normal scaling with the exponent .Comment: 13 pages, RevTeX 3.
Sequential quantum-enhanced measurement with an atomic ensemble
We propose a quantum-enhanced iterative (with steps) measurement scheme
based on an ensemble of two-level probes which asymptotically approaches
the Heisenberg limit , the number of quantum
resources. The protocol is inspired by Kitaev's phase estimation algorithm and
involves only collective manipulation and measurement of the ensemble. The
iterative procedure takes the shot-noise limited primary measurement with
precision to increasingly precise results
. A straightforward implementation of the algorithm
makes use of a two-component atomic cloud of Bosons in the precision
measurement of a magnetic field.Comment: 5 pages, 1 figur
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