Entanglement dynamics of photon pairs emitted from quantum dot

We present a model to derive the state of the photon pairs generated by the biexciton cascade decay of a self-assembled quantum dot, which agrees well with the experimental result. Furthermore we calculate the concurrence and entanglement sudden death is found in this system with temperature increasing, which prevents quantum dot emits entangled photon pairs at a high temperature. The relationship between the fine structure splitting and the sudden death temperature is provided too

Lattice study on ηc2\eta_{c2} and X(3872)

Properties of $2^{-+}$ charmonium $\eta_{c2}$ are investigated in quenched lattice QCD. The mass of $\eta_{c2}$ is determined to be 3.80(3) GeV, which is close to the mass of $D$-wave charmonium $\psi(3770)$ and in agreement with quark model predictions. The transition width of $\eta_{c2}\to \gamma J/\psi$ is also obtained with a value $\Gamma=3.8(9)$ keV. Since the possible $2^{-+}$ assignment to X(3872) has not been ruled out by experiments, our results help to clarify the nature of X(3872).Comment: 15 pages, 8 figures. typos, grammatical errors and some references corrected, redundant discussions deleted, conclusion does not change. published versio

Attenuation of sepsis-induced rat liver injury by epigallocatechin gallate via suppression of oxidative stress-related inflammation

Purpose: To evaluate the effect of epigallocatechin gallate (EGCG) on sepsis-induced liver injury in a rat model of sepsis established by cercal ligation and puncture (CLP). Methods: Male Wistar rats were randomly divided into 6 groups (n = 12): normal control, sepsis, dexamethasone (5 mg/kg), low-dose EGCG (12.5 mg/kg), medium-dose EGCG (25 mg/kg), and highdose EGCG (50 mg/kg) groups. Dexamethasone and EGCG were given once daily. Survival rates following CLP were recorded. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured to evaluate liver function. Tumor necrosis factor-α (TNF-α) and interleukin (IL)-10 were determined by ELISA. Superoxide dismutase (SOD) and levels of glutathione (GSH) and malondialdehyde (MDA) were assayed to evaluate oxidative stress. Protein and mRNA expression levels of heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor (Nrf2) were measured by Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. Results: Survival rates were significantly (p < 0.05) increased by EGCG (83.3 %) when compared to the untreated sepsis group (33.3 %) or dexamethasone-treated sepsis group (41.7 %). The increase in survival rates was associated with significant decreases in AST, ALT, MDA, and TNF-α, and significant elevations in SOD, GSH, and IL-10. QRT-PCR and Western blotting data indicate that there was increase in hepatic expression of Nrf-2 and HO-1 of EGCG-treated sepsis rats, relative to the untreated sepsis group. Conclusion: These results suggest that EGCG treatment reduces sepsis-induced liver injury and improves the survival rate of rats with polymicrobial sepsis by reducing oxidative stress via regulation of Nrf2/HO-1 signaling. These findings highlight the promising potential of EGCG for the treatment of sepsis. Keywords: Epigallocatechin gallate, Cecal ligation and puncture (CLP), Sepsis, Liver injury, Oxidative stress, Inflammatio

Photon scattering by an atomic ensemble coupled to a one-dimensional nanophotonic waveguide

We theoretically investigate the quantum scattering of a single-photon pulse interacting with an ensemble of $\Lambda$-type three-level atoms coupled to a one-dimensional waveguide. With an effective non-Hermitian Hamiltonian, we study the collective interaction between the atoms mediated by the waveguide mode. In our scheme, the atoms are randomly placed in the lattice along the axis of the one-dimensional waveguide, which closely corresponds to the practical condition that the atomic positions can not be controlled precisely in experiment. Many interesting optical properties occur in our waveguide-atom system, such as electromagnetically induced transparency (EIT) and optical depth. Moreover, we observe that strong photon-photon correlation with quantum beats can be generated in the off-resonant case, which provides an effective candidate for producing non-classical light in experiment. With remarkable progress in waveguide-emitter system, our scheme may be feasible in the near future.Comment: 10 pages,7 figure

Phase Compensation Enhancement of Photon Pair Entanglement Generated from Biexciton Decays in Quantum Dots

Exciton fine-structure splittings within quantum dots introduce phase differences between the two biexciton decay paths that greatly reduce the entanglement of photon pairs generated via biexciton recombination. We analyze this problem in the frequency domain and propose a practicable method to compensate the phase difference by inserting a spatial light modulator, which substantially improves the entanglement of the photon pairs without any loss.Comment: 4 pages, 3 figure

Experimental Trapped-ion Quantum Simulation of the Kibble-Zurek dynamics in momentum space

The Kibble-Zurek mechanism is the paradigm to account for the nonadiabatic dynamics of a system across a continuous phase transition. Its study in the quantum regime is hindered by the requisite of ground state cooling. We report the experimental quantum simulation of critical dynamics in the transverse-field Ising model by a set of Landau-Zener crossings in pseudo-momentum space, that can be probed with high accuracy using a single trapped ion. We test the Kibble-Zurek mechanism in the quantum regime in the momentum space and find the measured scaling of excitations is in accordance with the theoretical prediction.Comment: 10 pages, 3 figures Published in Scientific Reports, http://www.nature.com/articles/srep3338

(E)-N′-(4-Methoxy­benzyl­idene)benzohydrazide

In the title mol­ecule, C15H14N2O2, the dihedral angle between the benzene rings is 5.93 (17)°. In the crystal, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains propagating in [010]