Towards Interactive Image Inpainting via Sketch Refinement

One tough problem of image inpainting is to restore complex structures in the corrupted regions. It motivates interactive image inpainting which leverages additional hints, e.g., sketches, to assist the inpainting process. Sketch is simple and intuitive to end users, but meanwhile has free forms with much randomness. Such randomness may confuse the inpainting models, and incur severe artifacts in completed images. To address this problem, we propose a two-stage image inpainting method termed SketchRefiner. In the first stage, we propose using a cross-correlation loss function to robustly calibrate and refine the user-provided sketches in a coarse-to-fine fashion. In the second stage, we learn to extract informative features from the abstracted sketches in the feature space and modulate the inpainting process. We also propose an algorithm to simulate real sketches automatically and build a test protocol with different applications. Experimental results on public datasets demonstrate that SketchRefiner effectively utilizes sketch information and eliminates the artifacts due to the free-form sketches. Our method consistently outperforms the state-of-the-art ones both qualitatively and quantitatively, meanwhile revealing great potential in real-world applications. Our code and dataset are available

Broadband Squeezed Microwaves and Amplification with a Josephson Traveling-Wave Parametric Amplifier

Squeezing of the electromagnetic vacuum is an essential metrological technique used to reduce quantum noise in applications spanning gravitational wave detection, biological microscopy, and quantum information science. In superconducting circuits, the resonator-based Josephson-junction parametric amplifiers conventionally used to generate squeezed microwaves are constrained by a narrow bandwidth and low dynamic range. In this work, we develop a dual-pump, broadband Josephson traveling-wave parametric amplifier that combines a phase-sensitive extinction ratio of 56 dB with single-mode squeezing on par with the best resonator-based squeezers. We also demonstrate two-mode squeezing at microwave frequencies with bandwidth in the gigahertz range that is almost two orders of magnitude wider than that of contemporary resonator-based squeezers. Our amplifier is capable of simultaneously creating entangled microwave photon pairs with large frequency separation, with potential applications including high-fidelity qubit readout, quantum illumination and teleportation

Non-volatile, reconfigurable zero-static power optical routing for transistor-laser-based electronic-protonic processing

A growing demand for smart devices, wireless communication infrastructure, network hardware, and even the internet of things (IoT) is stimulating global demands on computation performance, network bandwidth, and power consumption. Chip-scale electronic-photonic processing platforms are recently becoming increasingly popular because optical links offer greater bandwidth and much better energy efficiency than electrical interconnects. The emerging transistor-laser-based platform stands out for its high electrical-to-optical efficiency. Because transistor lasers operate best at 980 nm, efficient optical interconnects at this wavelength need to be developed for energy-efficient computing platforms. Zero-static power, reconfigurable, optical-to-optical routing topologies are desired to significantly reduce power consumption. Moreover, any power saved from these routing elements will allow for a greater power budget for function-specific processors to be integrated into the system, thus improving computation performance even further. Phase change materials (PCMs) such as GeTe and Ge2Sb2Te5 are good candidates for zero-static power switching. A PCM has bi-stable states under room temperature. Its permittivity is significantly different between its crystalline and amorphous phases at 980 nm. In this work, we propose to develop a reconfigurable 1 x 2 optical switch by utilizing the low loss GeTe PCM to pave the way for the transistor-laser platform. Deposited as a thin-film patch on an optical ring resonator, GeTe achieves a phase shift between its two states without introducing significant loss in the device. The non-volatility of our proposed device will open up opportunities for other interesting applications such as non-volatile optical memory and the optical equivalence of the Field Programmable Gating Array (FPGA) technology.U of I Onlyundergraduate senior thesis not recommended for open acces

The Quest for Ideal Quantum Amplifiers

Faithful amplification and detection of weak signals are vital to a wide range of research fields, from quantum computing and dark matter detection to metrology and space communications. The increasingly complex systems for computing, metrology, and communication require more robust, performant, and scalable components. As a prominent example, quantum computing holds the potential to solve computational problems intractable for classical computers and advance healthcare, energy, climate, finance, and cybersecurity. However, the algorithmic complexity, finite qubit coherence, and imperfect control require quantum computers to scale to millions of physical qubits while maintaining low hardware error rates to impact real-world applications, necessitating quantum error correction and fast, high-fidelity, and simultaneous readout of a large number of qubits in each error correction cycle. Quantum amplifiers are a critical frontend quantum hardware to faithfully amplify single-photon-level readout signals above the orders of magnitude larger ambient and electronics noise at room temperature. However, existing quantum amplifiers face performance-scalability tradeoff and are thus challenging to meet the demands of large-scale information-critical quantum systems. This thesis aims to develop next-generation quantum amplifiers that achieve optimal noise performance, scalability, directionality, and processor integrability at the same time. We invent a new class of amplifiers, Floquet-mode traveling-wave parametric amplifiers (TWPAs), that solve the long-standing performance-scalability tradeoff and theoretically offer broadband directional amplification with over 99.9% quantum efficiency across a wide bandwidth. Furthermore, we experimentally demonstrate a low-loss Floquet TWPA using our recently developed planar implementation architecture, offering advantages such as 100x less measured material loss than conventional methods and compatibility with aluminum superconducting qubit fabrication. This architecture will enable direct on-chip integration of quantum amplifiers with superconducting quantum processors, reducing hardware infrastructure overhead and energy dissipation of large quantum systems. In addition, in our quest for ideal quantum amplifiers, we develop a general broadband isolation scheme, in conjunction with our Floquet TWPA implementation, as a promising avenue towards realizing nonreciprocal broadband amplifiers, which will significantly improve system-level efficiency and unlock new opportunities in experimental science.Ph.D

Engineering Purely Nonlinear Coupling between Superconducting Qubits Using a Quarton

Strong nonlinear coupling of superconducting qubits and/or photons is a critical building block for quantum information processing. Because of the perturbative nature of the Josephson nonlinearity, linear coupling is often used in the dispersive regime to approximate nonlinear coupling. However, this dispersive coupling is weak and the underlying linear coupling mixes the local modes, which, for example, distributes unwanted self-Kerr nonlinearity to photon modes. Here, we use the quarton to yield purely nonlinear coupling between two linearly decoupled transmon qubits. The quarton's zero ϕ^{2} potential enables an ultrastrong gigahertz-level cross-Kerr coupling, which is an order of magnitude stronger compared to existing schemes, and the quarton's positive ϕ^{4} potential can cancel the negative self-Kerr nonlinearity of qubits to linearize them into resonators. This ultrastrong cross-Kerr coupling between bare modes of qubit-qubit, qubit-photon, and even photon-photon is ideal for applications such as single microwave photon detection, ultrafast two-qubit gates, and readout

Investigation on the Deterioration Mechanism of Recycled Plaster

The deterioration mechanism of recycled plaster (R-P) was studied. The large specific surface area (SSA), improper preparation temperature, increased water requirement of R-P, and microstructure of its hardened body were analyzed by particle size distribution (PSD), Blaine method, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and nitrogen adsorption porosimetry. The results indicated that the properties of R-P were deteriorated, but its strength decreases from 50% at the same manufacturing process to 30%–40% at similar specific surface area. The analysis shows that the large SSA, poor morphology, narrow PSD, and increased internal detects give rise to increase of water requirement. In addition, the deterioration properties are caused by unsuitable temperature of preparation, loose structure, and large average pore diameter in hardened R-P as well

Floquet-Mode Traveling-Wave Parametric Amplifiers

Simultaneous ideal quantum measurements of multiple single-photon-level signals would advance applications in quantum information processing, metrology, and astronomy, but require the first amplifier to be simultaneously broadband, quantum limited, and directional. However, conventional traveling-wave parametric amplifiers support broadband amplification at the cost of increased added noise and are not genuinely directional due to non-negligible nonlinear backward wave generation. In this work, we introduce a new class of amplifiers which encode the information in the Floquet modes of the system. Such Floquet mode amplifiers prevent information leakage and overcome the trade-off between quantum efficiency (QE) and bandwidth. Crucially, Floquet mode amplifiers strongly suppress the nonlinear forward-backward wave coupling and are therefore genuinely directional and readily integrable with qubits, clearing another major obstacle towards broadband ideal quantum measurements. Furthermore, Floquet mode amplifiers are insensitive to out-of-band impedance mismatch, which otherwise may lead to gain ripples, parametric oscillations, and instability in conventional traveling-wave parametric amplifiers. Finally, we show that a Floquet mode Josephson traveling-wave parametric amplifier implementation can simultaneously achieve $>\!20\,$dB gain and a QE of $\eta/\eta_{\mathrm{ideal}}\!> 99.9\%$ of the quantum limit over more than an octave of bandwidth. The proposed Floquet scheme is also widely applicable to other platforms, such as kinetic inductance traveling-wave amplifiers and optical parametric amplifiers.Comment: 20 pages, 12 figures, appendice

Detection and Analysis of Sow Targets Based on Image Vision

In large-scale sow production, real-time detection and recognition of sows is a key step towards the application of precision livestock farming techniques. In the pig house, the overlap of railings, floors, and sows usually challenge the accuracy of sow target detection. In this paper, a non-contact machine vision method was used for sow targets perception in complex scenarios, and the number position of sows in the pen could be detected. Two multi-target sow detection and recognition models based on the deep learning algorithms of Mask-RCNN and UNet-Attention were developed, and the model parameters were tuned. A field experiment was carried out. The data-set obtained from the experiment was used for algorithm training and validation. It was found that the Mask-RCNN model showed a higher recognition rate than that of the UNet-Attention model, with a final recognition rate of 96.8% and complete object detection outlines. In the process of image segmentation, the area distribution of sows in the pens was analyzed. The position of the sow’s head in the pen and the pixel area value of the sow segmentation were analyzed. The feeding, drinking, and lying behaviors of the sow have been identified on the basis of image recognition. The results showed that the average daily lying time, standing time, feeding and drinking time of sows were 12.67 h(MSE 1.08), 11.33 h(MSE 1.08), 3.25 h(MSE 0.27) and 0.391 h(MSE 0.10), respectively. The proposed method in this paper could solve the problem of target perception of sows in complex scenes and would be a powerful tool for the recognition of sows