3,678 research outputs found
Protecting entanglement from correlated amplitude damping channel using weak measurement and quantum measurement reversal
Based on the quantum technique of weak measurement, we propose a scheme to
protect the entanglement from correlated amplitude damping decoherence. In
contrast to the results of memoryless amplitude damping channel, we show that
the memory effects play a significant role in the suppression of entanglement
sudden death and protection of entanglement under severe decoherence. Moreover,
we find that the initial entanglement could be drastically amplified by the
combination of weak measurement and quantum measurement reversal even under the
correlated amplitude damping channel. The underlying mechanism can be
attributed to the probabilistic nature of weak measurements.Comment: 11 pages, 5 figures, accepted by Quantum Information Processin
Boron Nitride Nanosheets for Metal Protection
Although the high impermeability of graphene makes it an excellent barrier to
inhibit metal oxidation and corrosion, graphene can form a galvanic cell with
the underlying metal that promotes corrosion of the metal in the long term.
Boron nitride (BN) nanosheets which have a similar impermeability could be a
better choice as protective barrier, because they are more thermally and
chemically stable than graphene and, more importantly, do not cause galvanic
corrosion due to their electrical insulation. In this study, the performance of
commercially available BN nanosheets grown by chemical vapor deposition as a
protective coating on metal has been investigated. The heating of the copper
foil covered with the BN nanosheet at 250 {\deg}C in air over 100 h results in
dramatically less oxidation than the bare copper foil heated for 2 h under the
same conditions. The electrochemical analyses reveal that the BN nanosheet
coating can increase open circuit potential and possibly reduce oxidation of
the underlying copper foil in sodium chloride solution. These results indicate
that BN nanosheets are a good candidate for oxidation and corrosion protection,
although conductive atomic force microscopy analyses show that the
effectiveness of the protection relies on the quality of BN nanosheets.Comment: With Supporting Informatio
Enhanced quantum teleportation in the background of Schwarzschild spacetime by weak measurements
It is commonly believed that the fidelity of quantum teleportation in the
gravitational field would be degraded due to the heat up by the Hawking
radiation. In this paper, we point out that the Hawking effect could be
eliminated by the combined action of pre- and post-weak measurements, and thus
the teleportation fidelity is almost completely protected. It is intriguing to
notice that the enhancement of fidelity could not be attributed to the
improvement of entanglement, but rather to the probabilistic nature of weak
measurements. Our work extends the ability of weak measurements as a quantum
technique to battle against gravitational decoherence in relativistic quantum
information.Comment: 9 pages, 5 figures, comments are welcom
Annihilation Type Radiative Decays of Meson in Perturbative QCD Approach
With the perturbative QCD approach based on factorization, we study the
pure annihilation type radiative decays and . We find that the branching ratio of is
, which is too small to be measured
in the current factories of BaBar and Belle. The branching ratio of is , which is just
at the corner of being observable in the factories. A larger branching
ratio is also predicted.
These decay modes will help us testing the standard model and searching for new
physics signals.Comment: 4 pages, revtex, with 1 eps figur
Robust Spin Squeezing Preservation in Photonic Crystal Cavities
We show that the robust spin squeezing preservation can be achieved by
utilizing detuning modification for an ensemble of N separate two-level atoms
embedded in photonic crystal cavities (PCC). In particular, we explore the
different dynamical behaviors of spin squeezing between isotropic and
anisotropic PCC cases when the atomic frequency is inside the band gap. In both
cases, it is shown that the robust preservation of spin squeezing is completely
determined by the formation of bound states. Intriguingly, we find that unlike
the isotropic case where steady-state spin squeezing varies smoothly when the
atomic frequency moves from the inside to the outside band edge, a sudden
transition occurs for the anisotropic case. The present results may be of
direct importance for, e.g., quantum metrology in open quantum systems.Comment: 6 pages, 4 figures, accepted by Laser Physics Letter
Enhancing teleportation of quantum Fisher information by partial measurements
The purport of quantum teleportation is to completely transfer information
from one party to another distant partner. However, from the perspective of
parameter estimation, it is the information carried by a particular parameter,
not the information of total quantum state that needs to be teleported. Due to
the inevitable noise in environment, we propose two schemes to enhance quantum
Fisher information (QFI) teleportation under amplitude damping noise with the
technique of partial measurements. We find that post partial measurement can
greatly enhance the teleported QFI, while the combination of prior partial
measurement and post partial measurement reversal could completely eliminate
the effect of decoherence. We show that, somewhat consequentially, enhancing
QFI teleportation is more economic than that of improving fidelity
teleportation. Our work extends the ability of partial measurements as a
quantum technique to battle decoherence in quantum information processing.Comment: Revised version, minor changes, accepted by Phys. Rev.
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