Construction of cobalt-copper bimetallic oxide heterogeneous nanotubes for high-efficient and low-overpotential electrochemical CO_(2) reduction

Currently,global warming and energy problems become more and more serious with the development of economy and the continuous consumption of fossil fuel,which are due to the release of greenhouse gas in the process of fossil fuel combustion and industrial manufacturing.

Bright 547-dimensional Hilbert-space entangled resource in 28-pair modes biphoton frequency comb from a reconfigurable silicon microring resonator

High-dimensional entanglement provides valuable resources for quantum technologies,including quantum communication,quantum optical coherence tomography,and quantum computing.Obtaining a high brightness and dimensional entanglement source has significant value.Here we utilize a tunable asymmetric Mach–Zehnder interferometer coupled silicon microring resonator with 100 GHz free spectral range to achieve this goal.With the strategy of the tunable coupler,the dynamical and extensive tuning range of quality factors of the microring can be obtained,and then the biphoton pair generation rate can be optimized.By selecting and characterizing 28 pairs from a more than 30-pair modes biphoton frequency comb,we obtain a Schmidt number of at least 23.4 and on-chip pair generation rate of 19.9 MHz/m W;under a low on-chip pump power,which corresponds to 547 dimensions Hilbert space in frequency freedom.These results will prompt the wide applications of quantum frequency comb and boost the further large density and scalable on-chip quantum information processing.

Near 100%spectral-purity photons from reconfigurable micro-rings

We propose an on-chip reconfigurable micro-ring to engineer the spectral-purity of photons.The micro-ring resonator is designed to be coupled by one or two asymmetric Mach-Zehnder interferometers and the coupling coefficients hence the quality-factors of the pump and the converted photons can be dynamically changed by the interferometer’s internal phase-shifter.We calculate the joint-spectrum function and obtain the spectral-purity of photons and Schmidt number under different phases.We show that it is a dynamical method to adjust the spectral-purity and can optimize the spectralpurity of photons up to near 100%.The condition for high-spectral-purity photons is ensured by the micro-ring itself,so it overcomes the trade-off between spectral purity and brightness in the traditional post-filtering method.This scheme is robust to fabrication variations and can be successfully applied in different fabrication labs and different materials.Such high-spectral-purity photons will be beneficial for quantum information processing like Boson sampling and other quantum algorithms.

Heralded path-entangled NOON states generation from a reconfigurable photonic chip

Maximal multi-photon entangled states,known as NOON states,play an essential role in quantum metrology.With the number of photons growing,NOON states are becoming increasingly powerful and advantageous for obtaining supersensitive and super-resolved measurements.In this paper,we propose a universal scheme for generating three-and four-photon path-entangled NOON states on a reconfigurable photonic chip via photons subtracted from pairs and detected by heralding counters.Our method is postselection free,enabling phase supersensitive measurements and sensing at the Heisenberg limit.Our NOON-state generator allows for integration of quantum light sources as well as practical and portable precision phase-related measurements.

Optimization of polyurethane-bonded thin overlay mixture designation for airport pavement

This research explored the application potential of PUM thin-overlay technology on airport rapid maintenance.The rapid curing process of polyurethane binder determines the limited time window for mixing and construction of polyurethane-bonded mixture(PUM),which presents significant difference with hot-mix asphalt(HMA)technology.Therefore,this research investigated and optimized the mix design of PUM for airport thin-overlay technology based on its thermosetting characteristics.First,limestone and basalt were comprehensively compared as an aggregate for PUM.Then,the effects of molding and curing conditions were studied in terms of mixing time,molding method,molding parameters and curing temperature.Statistical analysis was also conducted to evaluate the effects of gradation and particle size on PUM performances based on gray relational analysis(GRA),thus determining the key particle size to control PUM performances.Finally,the internal structural details of PUM were captured by X-ray CT scan test.The results demonstrated that it only took 12 hours to reach 75%of maximum strength at a curing temperature of 50°C,indicating an efficient curing process and in turn allowing short traffic delay.The internal structural details of PUM presented distribution of tiny pores with few connective voids,guaranteeing waterproof property and high strength.

Ultrasensitive tunable terahertz lithium niobate metasurface sensing based on bound states in the continuum

Lithium niobate’s substantial nonlinear optical and electro-optic coefficients have recently thrust it into the limelight.This study presents a thorough review of bound states in the continuum(BICs)in lithium niobate metasurfaces,also suggesting their potential for sensing applications.We propose an all-dielectric tunable metasurface that offers high Q factor resonances in the terahertz range,triggered by symmetry-protected BICs.With exceptional sensitivity to changes in the refractive index of the surrounding medium,the metasurface can reach a sensitivity as high as 947 GHz/RIU.This paves the way for ultrasensitive tunable terahertz sensors,offering an exciting path for further research.

Experimental demonstration of quantum transport enhancement using time-reversal symmetry breaking on a silicon photonic chip

The continuous-time quantum walk is a basic model for studying quantum transport and developing quantum-enhanced algorithms. Recent studies show that by introducing a phase into the standard continuous-time quantum walk model, the time-reversal symmetry can be broken without changing the Hermitian property of the Hamiltonian. The time-reversal symmetry breaking quantum walk shows advantages in quantum transport, such as perfect state transfer, directional control, transport speedup, and quantum transport efficiency enhancement. In this work, we implement the time-reversal symmetry breaking quantum walks on a reconfigurable silicon photonic chip and demonstrate the enhancement introduced by breaking time-reversal symmetry. Perfect state transfer on a three-site ring, a quantum switch implemented on a six-site graph, and transport speedup using a linear chain of triangles are demonstrated with high fidelity. Time-reversal asymmetry has also been used in a simplified light-harvesting model,implying the potential of time-reversal symmetry breaking in photosynthesis investigations.

On-chip multiphoton Greenberger-Horne Zeilinger state based on integrated frequency combs

One of the most important multipartite entangled states,Greenberger-Horne-Zeilinger state(GHZ),serves as a fundamental resource for quantum foundat ion test,quantum communication and quantum computation.To increase the number of entangled particles,significant experimental efforts should been invested due to the complexity of optical setup and the difficulty in maintaining the coherence condition for high-fidelity GHZ state.Here,we propose an ultra-integrated scalable on-chip GHZ state generation scheme based on frequency combs.By designing several microrings pumped by different lasers,multiple partially overlapped quantum frequency combs are generated to supply as the basis for on-chip polarization-encoded GHZ state with each qubit occupying a certain spectral mode.Both even and odd numbers of GHZ states can be engineered with constant small number of integrated components and easily scaled up on the same chip by only adjusting one of the pumnp wavelengths.In addition,we give the on-chip design of projection measurement for characterizing GHZ states and show the reconfigurability of the state.Our proposal is rather simple and feasible within the existing fabrication technologies and we believe it will boost the development of multiphoton technologies.