801 research outputs found
Experimental Free-Space Distribution of Entangled Photon Pairs over a Noisy Ground Atmosphere of 13km
We report free-space distribution of entangled photon pairs over a noisy
ground atmosphere of 13km. It is shown that the desired entanglement can still
survive after the two entangled photons have passed through the noisy ground
atmosphere. This is confirmed by observing a space-like separated violation of
Bell inequality of . On this basis, we exploit the distributed
entangled photon source to demonstrate the BB84 quantum cryptography scheme.
The distribution distance of entangled photon pairs achieved in the experiment
is for the first time well beyond the effective thickness of the aerosphere,
hence presenting a significant step towards satellite-based global quantum
communication.Comment: 4 pages, 3 figure
catena-Poly[[(isoquinoline-κN)(triphenylphospane-κP)copper(I)]-μ-thiocyanato-κ2 N:S]
In the title coordination compound, [Cu(NCS)(C9H7N)(C18H15P)]n, the CuI atom is tetrahedrally coordinated by one N atom from an isoquinoline ligand, one P atom from a triphenylphospane ligand, and one N and one S atom from two thiocyanate anions. The thiocyanide anions bridge the CuI atoms into a chain along [100]. π–π interactions between the pyridine and benzene rings of the isoquinoline ligands connect the chains [centroid-to-centroid distance = 3.722 (3) Å]
Holographic Storage of Biphoton Entanglement
Coherent and reversible storage of multi-photon entanglement with a multimode
quantum memory is essential for scalable all-optical quantum information
processing. Although single photon has been successfully stored in different
quantum systems, storage of multi-photon entanglement remains challenging
because of the critical requirement for coherent control of photonic
entanglement source, multimode quantum memory, and quantum interface between
them. Here we demonstrate a coherent and reversible storage of biphoton
Bell-type entanglement with a holographic multimode atomic-ensemble-based
quantum memory. The retrieved biphoton entanglement violates Bell's inequality
for 1 microsecond storage time and a memory-process fidelity of 98% is
demonstrated by quantum state tomography.Comment: 5 pages, 4 figures, accepted by Phys. Rev. Let
Coordination Dynamics and Coordination Mechanism of a New Type of Anticoagulant Diethyl Citrate with Ca 2+
Diethyl citrate (Et2Cit) is a new potential anticoagulant. The coordination dynamics and coordination mechanism of Et2Cit with Ca2+ ions and the effect of pH on the complex were examined. The result was compared with that for the conventional anticoagulant sodium citrate (Na3Cit). The reaction order (n) of Et2Cit and Na3Cit with Ca2+ was 2.46 and 2.44, respectively. The reaction rate constant (k) was 120 and 289 L·mol−1·s−1. The reverse reaction rate constant (kre) was 0.52 and 0.15 L·mol−1·s−1, respectively. It is indicated that the coordination ability of Et2Cit with Ca2+ was weaker than that of Na3Cit. However, the dissociation rate of the calcium complex of Et2Cit was faster than that of Na3Cit. Increased pH accelerated the dissociation rate of the complex and improved its anticoagulant effect. The Et2Cit complex with calcium was synthesized and characterized by elemental analysis, XRD, FT-IR, 1H NMR, and ICP. These characteristics indicated that O in –COOH and C–O–C of Et2Cit was coordinated with Ca2+ in a bidentate manner with 1 : 1 coordination proportion; that is, complex CaEt2Cit was formed. Given that CaEt2Cit released Ca2+ more easily than Na3Cit, a calcium solution was not needed in intravenous infusions using Et2Cit as anticoagulant unlike using Na3Cit. Consequently, hypocalcemia and hypercalcemia were avoided
A nonequilibrium Green's function study of thermoelectric properties in single-walled carbon nanotubes
The phonon and electron transport in single-walled carbon nanotubes (SWCNT)
are investigated using the nonequilibrium Green's function approach. In zigzag
SWCNT (, 0) with , the thermal conductance is mainly
attributed to the phonon transport, while the electron only has few percentage
contribution. The maximum value of the figure of merit () is about 0.2 in
this type of SWCNT. The is considerably larger in narrower SWCNT because
of enhanced Seebeck coefficient. is smaller in the armchair SWCNT, where
Seebeck coefficient is small due to zero band gap. It is found that the cluster
isotopic doping can reduce the phonon thermal conductance obviously and enhance
the value of . The uniaxial elongation and compress strain depresses
phonons in whole frequency region, leading to the reduction of the phonon
thermal conductance in whole temperature range. Interestingly, the elongation
strain can affect the phonon transport more seriously than the compress strain,
because the high frequency mode is completely filtered out under elongation
strain . The strain also has important effect on the subband
edges of the electron band structure by smoothing the steps in the electron
transmission function. The is decreased by strain as the reduction in the
electronic conductance overcomes the reduction in the thermal conductance.Comment: 30 pages, 15 figs, accepted by J. Appli. Phy
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