5,776 research outputs found
Enhancing quantum entanglement for continuous variables by a coherent superposition of photon subtraction and addition
We investigate how the entanglement properties of a two-mode state can be
improved by performing a coherent superposition operation of photon subtraction
and addition, proposed by Lee and Nha [Phys. Rev. A 82, 053812 (2010)], on each
mode. We show that the degree of entanglement, the EPR-type correlation, and
the performance of quantum teleportation can be all enhanced for the output
state when the coherent operation is applied to a two-mode squeezed state. The
effects of the coherent operation are more prominent than those of the mere
photon subtraction and the addition particularly in the small squeezing regime,
whereas the optimal operation becomes the photon subtraction in the
large-squeezing regime.Comment: 6 pages, 6 figures, published versio
Loophole-free Bell test for continuous variables via wave and particle correlations
We derive two classes of multi-mode Bell inequalities under local realistic
assumptions, which are violated only by the entangled states negative under
partial transposition in accordance with the Peres conjecture. Remarkably, the
failure of local realism can be manifested by exploiting wave and particle
correlations of readily accessible continuous-variable states, with very large
violation of inequalities insensitive to detector-efficiency, which makes a
strong case for a loophole-free test.Comment: 4 pages, published versio
Reply to the comment on "Loophole-free Bell test for continuous variables via wave and particle correlations"
In a recent note, Cavalcanti and Scarani (CS) constructed a counter
local-hidden-variable model to explain the violation of our inequalities in
Phys. Rev. Lett. 105, 170404 (2010). Here, we briefly discuss some issues in
response to the comments raised by CS.Comment: published versio
Tonicity response element binding protein associated with neuronal cell death in the experimental diabetic retinopathy
AIM: To study the contribution of tonicity response element binding protein (TonEBP) in retinal ganglion cell (RGC) death of diabetic retinopathy (DR).
METHODS: Diabetes was induced in C57BL/6 mice by five consecutive intraperitoneal injections of 55 mg/kg streptozotocin (STZ). Control mice received vehicle (phosphate -buffered saline). All mice were killed 2mo after injections, and the extent of cell death and the protein expression levels of TonEBP and aldose reductase (AR) were examined.
RESULTS: The TonEBP and AR protein levels and the death of RGC were significantly increased in the retinas of diabetic mice compared with controls 2mo after the induction of diabetes. Terminal deoxynucleotidyl transferase (TdT) -mediated dUTP nick end labeling (TUNEL) -positive signals co -localized with TonEBP immunoreactive RGC. These changes were increased in the diabetic retinas compared with controls.
CONCLUSION: The present data show that AR and TonEBP are upregulated in the DR and TonEBP may contribute to apoptosis of RGC in the DR.close2
The First Room-Temperature Ambient-Pressure Superconductor
For the first time in the world, we succeeded in synthesizing the
room-temperature superconductor ( K, 127C) working at
ambient pressure with a modified lead-apatite (LK-99) structure. The
superconductivity of LK-99 is proved with the Critical temperature (),
Zero-resistivity, Critical current (), Critical magnetic field (),
and the Meissner effect. The superconductivity of LK-99 originates from minute
structural distortion by a slight volume shrinkage (0.48 %), not by external
factors such as temperature and pressure. The shrinkage is caused by Cu
substitution of Pb(2) ions in the insulating network of Pb(2)-phosphate
and it generates the stress. It concurrently transfers to Pb(1) of the
cylindrical column resulting in distortion of the cylindrical column interface,
which creates superconducting quantum wells (SQWs) in the interface. The heat
capacity results indicated that the new model is suitable for explaining the
superconductivity of LK-99. The unique structure of LK-99 that allows the
minute distorted structure to be maintained in the interfaces is the most
important factor that LK-99 maintains and exhibits superconductivity at room
temperatures and ambient pressure
Testing nonclassicality and non-Gaussianity in phase space
We theoretically propose and experimentally demonstrate a nonclassicality
test of single-mode field in phase space, which has an analogy with the
nonlocality test proposed by Banaszek and Wodkiewicz [Phys. Rev. Lett. 82, 2009
(1999)]. Our approach to deriving the classical bound draws on the fact that
the Wigner function of a coherent state is a product of two independent
distributions as if the orthogonal quadratures (position and momentum) in phase
space behave as local realistic variables. Our method detects every pure
nonclassical Gaussian state, which can also be extended to mixed states.
Furthermore, it sets a bound for all Gaussian states and their mixtures,
thereby providing a criterion to detect a genuine quantum non-Gaussian state.
Remarkably, our phase-space approach with invariance under Gaussian unitary
operations leads to an optimized test for a given non-Gaussian state. We
experimentally show how this enhanced method can manifest quantum
non-Gaussianity of a state by simply choosing phase-space points appropriately,
which is essentially equivalent to implementing a squeezing operation on a
given state.Comment: 5 pages and 3 figures with Supplemental Material, published versio
Ultrafast Magneto-Acoustics in Nickel Films
We report about the existence of magneto-acoustic pulses propagating in a
200-nm-thick ferromagnetic nickel film excited with 120 fs laser pulses. They
result from the coupling between the magnetization of the ferromagnetic film
and the longitudinal acoustic waves associated to the propagation of the
lattice deformation induced by the femtosecond laser pulses. The
magneto-acoustic pulses are detected from both the front and back sides of the
film, using the time-resolved magneto-optical Kerr technique, measuring both
the time dependent rotation and ellipticity. We show that the propagating
acoustic pulse couples efficiently to the magnetization and is strong enough to
induce a precession of the magnetization. It is due to a transient change of
the crystalline anisotropy associated to the lattice deformation. It is shown
that the results can be interpreted by combining the concepts of acoustic pulse
propagation and ultrafast magnetization dynamics.Comment: 4 pages, 3 figures, Submitted to Physical Review Letters on November
30th 201
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