Generation of microwave photon perfect W states of three coupled superconducting resonators

We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum interference device(dc-SQUID).With suitable external magnetic fluxes applied to the dc-SQUID symmetry loops,on-chip tunable interactions between neighboring resonators can be realized,and different perfect W states can be deterministically created on-demand in one step.Numerical simulations show that high-fidelity target states can be generated and our scheme is robust against imperfect parameter tuning and environment-induced decoherence.The present work may have potential applications for implementing quantum computation and quantum information processing based on microwave photons.

Angular disturbance prediction for countermeasure launcher in active protection system of moving armored vehicle based on an ensemble learning method

The active protection system(APS),usually installed on the turret of armored vehicles,can significantly improve the vehicles’survivability on the battlefield by launching countermeasure munitions to actively intercept incoming threats.However,uncertainty over the launch angle of the countermeasure is increased due to angular disturbances when the off-road armored vehicle is moving over rough terrain.Therefore,accurate and comprehensive angular disturbance prediction is essential to the real-time monitoring of the countermeasure launch angle.In this paper,a deep ensemble learning(DEL)-based approach is proposed to predict the angular disturbances of the countermeasure launcher in the APS based on previous time-series information.In view of the intricate temporal attribute of angular disturbance prediction,the sampling information of historical time series measured by an inertial navigation device is adopted as the input of the developed DEL model.Then,the recursive multi-step(RMS)prediction strategy and multi-output(MO)prediction strategy are combined with the DEL model to perform the final angular disturbance prediction for the countermeasure launcher in the APS of a moving armored vehicle.The proposed DEL model is validated by using the different datasets from real experiments.The results reveal that this approach can be used to accurately predict angular disturbances,with the maximum absolute error of each DOF less than 0.1°.

Nonlocal effect on resonant radiation force exerted on semiconductor coupled quantum well nanostructures

Based on the microscopic nonlocal optical response theory, the resonant radiation force exerted on a semiconductorcoupled quantum well nanostructure(CQWN), induced by the nonlocal interaction between lasers and electrons in conduction bands, is investigated for two different polarized states. The numerical results show that the spatial nonlocality of optical response can cause a radiation shift(blue-shift) for the spectrum of the resonant radiation force, which is dependent on the CQWN width ratio, the barrier height, and polarized states sensitively. It is also confirmed that the resonant radiation force is steerable by the incident and polarized directions of incident light. This work may provide an advantageous method for detecting internal quantum properties of nanostructures, and open novel and raising possibilities for optical manipulation of nano-objects using laser-induced radiation force.

Atomic Pt anchored on hierarchically porous monolithic carbon nanowires as high-performance catalyst for liquid hydrogenation

Monolithic catalysts play a crucial role in various catalytic applications,e.g.,chemical synthesis,energy conversion,and environmental treatment,but their catalytic efficiency is often limited by the restricted mass transfer and insufficient exposure of active sites.Herein,we present a dual-templating strategy to fabricate atomic Pt dispersed on monolithic N-doped mesoporous carbon nanowires(Pt_(1)/NMCW)with abundant super-/macropores,which,as monolithic catalyst,exhibits high catalytic performance in hydrogenation of 4-nitrophenol(4-NP).During synthesis,triblock copolymer(Pluronic F127)is employed as a primary soft template to generate the mesoporous structured carbon nanowires to improve the accessibility of Pt single sites;KCl crystallite is used as a secondary hard template to create the super-/macropores,which are beneficial for enhancing the mass transfer efficiency.Thanks to the dual-templating strategy that creates the monolithic carbon nanowires with hierarchically porous structure,the obtained Pt_(1)/NMCW shows highly enhanced catalytic activity in 4-NP hydrogenation,outperforming its analogue synthesized without using KCl as template and being comparable to the nano-powder catalyst(i.e.,atomic Pt loaded on the Ndoped carbon nanospheres,Pt_(1)/NCS).

Cobalt single atoms supported on monolithic carbon with a hollow-on-hollow architecture for efficient transfer hydrogenations

Single-atom catalysts(SACs)have received considerable attention in hydrogenation of nitroaromatic compounds to aromatic amines.In order to enhance the exposure of single atoms and overcome the mass transfer limitation,construction of hierarchical porous supports for single atoms is highly desirable.Herein,we report a straightforward method to synthesize Co single-atoms supported on a hollow-on-hollow structured carbon monolith(Co_(1)/HOHC-M)by pyrolysis ofα-cellulose monolith loaded with PS-core@ZnCo-zeolite imidazolate frameworks-shell nanospheres(PS@Zn-ZIFs/α-cellulose).The hollow-on-hollow structure consists of a large hollow void with a diameter of~290 nm(derived from the decomposition of polystyrene(PS)nanospheres)and a thin shell with hollow spherical pores with a diameter of~10 nm(derived from the evaporation of ZnO nanoparticles that are in-situ formed during pyrolysis in the presence of CO_(2)fromα-cellulose decomposition).Benefitting from the hierarchically porous architecture,the Co_(1)/HOHC-M exhibits excellent catalytic performance(reaction rate of 421.6 mmol·gCo^(-1)·h^(−1))in the transfer hydrogenation of nitrobenzene to aniline,outperforming the powdered sample of Co_(1)/HCS without the hollow spherical mesopores(reaction rate of 353.8 mmol·gCo^(-1)·h^(−1)).It is expected that this strategy could be well extended in heterogeneous catalysis,given the wide applications of porous carbon-supported single-atom catalysts.

Neighbor Distinguishing Total Choice Number of Sparse Graphs via the Combinatorial Nullstellensatz

Let G =（V, E） be a graph and Ф ： V tA E → {1, 2,..., k） be a total-k-coloring of G. Let f（v）（S（v）） denote the sum（set） of the color of vertex v and the colors of the edges incident with v. The total coloring Ф is called neighbor sum distinguishing if （f（u） ≠ f（v）） for each edge uv∈ E（G）. We say that Фis neighbor set distinguishing or adjacent vertex distinguishing if S（u） ≠ S（v） for each edge uv ∈ E（G）. For both problems, we have conjectures that such colorings exist for any graph G if k 〉 △（G） ＋ 3. The maximum average degree of G is the maximum of the average degree of its non-empty subgraphs, which is denoted by mad （G）. In this paper, by using the Combinatorial Nullstellensatz and the discharging method, we prove that these two conjectures hold for sparse graphs in their list versions. More precisely, we prove that every graph G with maximum degree A（G） and maximum average degree mad（G） has ch＇＇∑（G） 〈 △（G） ＋ 3 （where ch＇＇∑（G） is the neighbor sum distinguishing total choice number of G） if there exists a pair （k, m） ∈ {（6, 4）, （5, 18/5）, （4, 16）} such that △（G） 〉 k and mad （G） 〈 m.

Improvement on the manipulation of a single nitrogen-vacancy spin and microwave photon at single-quantum level

It remains a great challenge to realize direct manipulation of a nitrogen-vacancy(NV)spin at the single-quantum level with a microwave(MW)cavity.As an alternative,a hybrid system with the spin–phonon–photon triple interactions mediated by a squeezed cantilever-type harmonic resonator is proposed.According to the general mechanical parametric amplification of this in-between phonon mode,the direct spin–phonon and photon–phonon couplings are both exponentially enhanced,which can even further improve the coherent manipulation of a single NV spin and MW photon with a higher efficiency.In view of this triple system with enhanced couplings and the additional sideband adjustable designs,this scheme may provide a more efficient phonon-mediated platform to bridge or manipulate the MW quantum and a single electron spin coherently.It is also hoped to evoke wider applications in the areas of quantum state transfer and preparation,ultrasensitive detection and quantum nondestructive measurement,etc.

In situ Formed Fan-Shaped Nanowires in Biomorphic SiO2：A Multidimensional Composite of Hierarchical Porous Material and Organic Pollutant Adsorption Behavior

Fan-shaped SiO2 nanowires modified SiO2@C composites with a bio-inspired hierarchical porous structure and a high accessible surface area were prepared by in situ molten salt template method.The combination of biogenic hierarchical porous structure and one-dimensional nanostructure with similar features was successfully obtained by one-pot heat treatment in the presence of rice husk SiO2 with SiO2 acting as precursor and ZnCl2 acting as molten salt and growth template.A large amount of fan-shaped SiO2 nanowires with numerous tiny branches sprouting from the central nanowires were grown in the inter-porous epidermis and on the surface of rice husk SiO2 for temperatures up to 1200 ℃.The in situ ZnCl2 molten salt template base-growth mechanism is responsible for the initial formation of SiO2/ZnCl2 co-melting nanowires and the subsequent growth of fan-shaped SiO2 nanowires.The as-prepared samples have been successfully employed as organic absorbers with high efficiency in the field of wastewater treatment.

Total-coloring of Sparse Graphs with Maximum Degree 6

Given a graph G=(V,E)and a positive integer k,a k-total-coloring of G is a mappingφ:V⋃E→{1,2,⋯,k}such that no two adjacent or incident elements receive the same color.The central problem of the total-colorings is the Total Coloring Conjecture,which asserts that every graph of maximum degreeΔadmits a(Δ+2)-total-coloring.More precisely,this conjecture has been verified forΔ≤5,and it is still open whenΔ=6,even for planar graphs.Let mad(G)denote the maximum average degree of the graph G.In this paper,we prove that every graph G withΔ(G)=6 and mad(G)<23/5 admits an 8-total-coloring.