Phase Reversal Diffraction in incoherent light

Phase reversal occurs in the propagation of an electromagnetic wave in a negatively refracting medium or a phase-conjugate interface. Here we report the experimental observation of phase reversal diffraction without the above devices. Our experimental results and theoretical analysis demonstrate that phase reversal diffraction can be formed through the first-order field correlation of chaotic light. The experimental realization is similar to phase reversal behavior in negatively refracting media.Comment: 8 pages, 5 figure

A device for feasible fidelity, purity, Hilbert-Schmidt distance and entanglement witness measurements

A generic model of measurement device which is able to directly measure commonly used quantum-state characteristics such as fidelity, overlap, purity and Hilbert-Schmidt distance for two general uncorrelated mixed states is proposed. In addition, for two correlated mixed states, the measurement realizes an entanglement witness for Werner's separability criterion. To determine these observables, the estimation only one parameter - the visibility of interference, is needed. The implementations in cavity QED, trapped ion and electromagnetically induced transparency experiments are discussed.Comment: 6 pages, 3 figure

Catalytic Deoxygenation of Bio-Oil Model Compounds over Acid–Base Bifunctional Catalysts

An acid–base bifunctional catalyst was synthesized by treating a natural mixed-metal oxide, serpentine, with sulfuric acid. Catalyst characterization revealed that the number of acidic and basic sites increased after the acid treatment largely due to an increase in surface area. However, stronger acid sites were also introduced by the formation of bridged hydroxyl groups between a Si atom and a heteroatom, as inferred by H NMR and NH₃-TPD analysis. Results from SEM-EDS and ¹H NMR suggested that the acid and base sites were in close proximity. Catalytic conversions of carbohydrate-derived bio-oil model compounds were performed over different acid/base catalysts. Eight single bio-oil model compounds and two binary mixtures were used. The reactivity of the model compounds was found to be strongly correlated to the number of oxygen-containing functional groups in the reactant. The results from the binary mixtures showed that the acid–base bifunctional catalyst had the highest activity in aldol condensation reactions. The best deoxygenation performance was also observed with the bifunctional catalyst for the model compounds. Reaction pathways were proposed on the basis of an isotope labeling study. Deoxygenation reactions were found to be promoted by the cooperative catalysis between closely located acid and base sites

Single-atom cadmium-N4 sites for rechargeable Li–CO2 batteries with high capacity and ultra-long lifetime

The rechargeable Li–CO2 battery shows great potential in civil, military, and aerospace fields due to its high theoretical energy density and CO2 capture capability. To facilitate the practical application of Li–CO2 battery, the design of efficient, low-cost, and robust non-noble metal cathodes to boost CO2 reduction/evolution kinetics is highly desirable yet remains a challenge. Herein, single-atom cadmium is reported with a Cd-N4 coordination structure enable rapid kinetics of both the discharge and recharge process when employed as a cathode catalyst, and thus facilitates exceptional rate performance in a Li–CO2 battery, even up to 10 A g−1, and remains stable at a high current density (100 A g−1). An unprecedented discharge capacity of 160045 mAh g−1 is attained at 500 mA g−1. Excellent cycling stability is maintained for 1685 and 669 cycles at 1 A g−1 and capacities of 0.5 and 1 Ah g−1, respectively. Density functional theory calculations reveal low energy barriers for both Li2CO3 formation and decomposition reactions during the respective discharge and recharge process, evidencing the high catalytic activity of single Cd sites. This study provides a simple and effective avenue for developing highly active and stable single-atom non-precious metal cathode catalysts for advanced Li–CO2 batteries