Phase retrieval with background information

Phase retrieval problem has been studied in various applications. It is an inverse problem without the standard uniqueness guarantee. To make complete theoretical analyses and devise efficient algorithms to recover the signal is sophisticated. In this paper, we come up with a model called \textit{phase retrieval with background information} which recovers the signal with the known background information from the intensity of their combinational Fourier transform spectrum. We prove that the uniqueness of phase retrieval can be guaranteed even considering those trivial solutions when the background information is sufficient. Under this condition, we construct a loss function and utilize the projected gradient descent method to search for the ground truth. We prove that the stationary point is the global optimum with probability 1. Numerical simulations demonstrate the projected gradient descent method performs well both for 1-D and 2-D signals. Furthermore, this method is quite robust to the Gaussian noise and the bias of the background information

Multiple Scattering Media Imaging via End-to-End Neural Network

Recovering the image of an object from its phaseless speckle pattern is difficult. Let alone the transmission matrix is unknown in multiple scattering media imaging. Double phase retrieval is a recently proposed efficient method which recovers the unknown object from its phaseless measurements by two steps with phase retrieval. In this paper, we combine the two steps in double phase retrieval and construct an end-to-end neural network called TCNN(Transforming Convolutional Neural Network) which directly learns the relationship between the phaseless measurements and the object. TCNN contains a special layer called transform layer which aims to be a bridge between different transform domains. Tested by the empirical data provided in\cite{Metzler2017Coherent}, images can be recovered by TCNN with comparable quality compared with state-of-the-art methods. Not only the transmission matrix needn't to be calculated but also the time to recover the object can be hugely reduced once the parameters of TCNN are stable

Phase Retrieval via Sparse Wirtinger Flow

Phase retrieval(PR) problem is a kind of ill-condition inverse problem which can be found in various of applications. Utilizing the sparse priority, an algorithm called SWF(Sparse Wirtinger Flow) is proposed in this paper to deal with sparse PR problem based on the Wirtinger flow method. SWF firstly recovers the support of the signal and then updates the evaluation by hard thresholding method with an elaborate initialization. Theoretical analyses show that SWF has a geometric convergence for any $k$ sparse $n$ length signal with the sampling complexity $\mathcal{O}(k^2\mathrm{log}n)$. To get $\varepsilon$ accuracy, the computational complexity of SWF is $\mathcal{O}(k^3n\mathrm{log}n\mathrm{log}\frac{1}{\varepsilon})$. Numerical tests also demonstrate that SWF performs better than state-of-the-art methods especially when we have no priori knowledge about sparsity $k$. Moreover, SWF is also robust to the nois

A New Concept of Deep Reinforcement Learning based Augmented General Sequence Tagging System

In this paper, a new deep reinforcement learning based augmented general sequence tagging system is proposed. The new system contains two parts: a deep neural network (DNN) based sequence tagging model and a deep reinforcement learning (DRL) based augmented tagger. The augmented tagger helps improve system performance by modeling the data with minority tags. The new system is evaluated on SLU and NLU sequence tagging tasks using ATIS and CoNLL-2003 benchmark datasets, to demonstrate the new system's outstanding performance on general tagging tasks. Evaluated by F1 scores, it shows that the new system outperforms the current state-of-the-art model on ATIS dataset by 1.9% and that on CoNLL-2003 dataset by 1.4%.Comment: Published at 2018 COLIN

A Neural Transition-based Model for Nested Mention Recognition

It is common that entity mentions can contain other mentions recursively. This paper introduces a scalable transition-based method to model the nested structure of mentions. We first map a sentence with nested mentions to a designated forest where each mention corresponds to a constituent of the forest. Our shift-reduce based system then learns to construct the forest structure in a bottom-up manner through an action sequence whose maximal length is guaranteed to be three times of the sentence length. Based on Stack-LSTM which is employed to efficiently and effectively represent the states of the system in a continuous space, our system is further incorporated with a character-based component to capture letter-level patterns. Our model achieves the state-of-the-art results on ACE datasets, showing its effectiveness in detecting nested mentions.Comment: EMNLP 201

The effect of hidden color channels on Nucleon-Nucleon interaction

This letter reports the nucleon-nucleon($NN$) interaction obtained from multi-channel, including hidden color channels, coupling quark model calculation. The results show that the hidden color channels coupling provides the intermediate range attraction which is usually assumed to be due to multi-$\pi$ or $\sigma$ meson exchange and that the short and intermediate range $NN$ interaction can be described solely by the fundamental quark-gluon degree of freedom of QCD.Comment: 5 pages, 5 figure

Possible HH-like dibaryon states with heavy quarks

Possible $H$-like dibaryon states $\Lambda_{c}\Lambda_{c}$ and $\Lambda_{b}\Lambda_{b}$ are investigated within the framework of quark delocalization color screening model. The results show that the interaction between two $\Lambda_{c}$'s is repulsive, so it cannot be bound state by itself. However, the strong attraction in $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ channels and the strong channel coupling, due to the central interaction of one-gluon-exchange and one-pion-exchange, among $\Lambda_{c}\Lambda_{c}$, $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ push the energy of system below the threshold of $\Lambda_{c}\Lambda_{c}$ by $22$ MeV. The corresponding system $\Lambda_{b}\Lambda_{b}$ has the similar properties as that of $\Lambda_{c}\Lambda_{c}$ system, and a bound state is also possible in $\Lambda_{b}\Lambda_{b}$ system.Comment: 6 pages, 4 figures, 3 table

Investigating the excited Ωc0\Omega^{0}_{c} states through ΞcK\Xi_{c}K and Ξc′K\Xi^{'}_{c}K decay channels

Inspired by the five newly observed $\Omega^{0}_{c}$ states by the LHCb detector, we study the $\Omega_{c}^{0}$ states as the $S-$wave molecular pentaquarks with $I=0$, $J^{P}=\frac{1}{2}^{-}$, $\frac{3}{2}^{-}$, and $\frac{5}{2}^{-}$ by solving the RGM equation in the framework of chiral quark model. Both the energies and the decay widths are obtained in this work. Our results suggest that $\Omega_{c}(3119)^{0}$ can be explained as an $S-$wave resonance state of $\Xi D$ with $J^{P}=\frac{1}{2}^{-}$, and the decay channels are the $S-$wave $\Xi_{c} K$ and $\Xi^{'}_{c}K$ . Other reported $\Omega^{0}_{c}$ states cannot be obtained in our present calculation. Another $\Omega_{c}^{0}$ state with much higher mass 3533 MeV with $J^{P}=\frac{5}{2}^{-}$ is also obtained. In addition, the calculation is extended to the $\Omega_{b}^{0}$ states, similar results as that of $\Omega^{0}_{c}$ are obtained.Comment: 6 pages, 2 figure

Theoretical study of a d∗d^{*} resonance in 3G3^{3}G_{3} partial wave of nucleon-nucleon scattering

Inspired by the recent results of the WASA-at-COSY Collaboration, in which they found a resonance pole in the coupled $^{3}D_{3}$ - $^{3}G_{3}$ partial waves as expected from the $d^{*}$ resonance hypothesis, we calculated the resonance structure in the coupled $^{3}D_{3}$ - $^{3}G_{3}$ partial wave phase shifts of nucleon-nucleon scattering in the framework of two constituent quark models: the quark delocalization color screening model and the chiral quark model. Our results show that there is a resonance $^{7}S_{3}^{\Delta\Delta}$ in the coupled $^{3}D_{3}^{NN}$ and $^{3}G_{3}^{NN}$ partial waves in both of these two models, which is in accordance with the expectation from the $d^{*}$ resonance structure. The resonance shape in the $^{3}D_{3}^{NN}$ partial wave is remarkable, whereas in the $^{3}G_{3}^{NN}$ phase shifts there is a small rise around the resonance energy. This result is in agreement with the recent experimental observations of WASA-at-COSY Collaboration.Comment: 5 pages, 3 figure

Further study of the NΩN\Omega dibaryon within constituent quark models

Inspired by the discovery of the dibaryon $d^{*}$ and the experimental search of $N\Omega$ dibaryon with the STAR data, we study the strange dibaryon $N\Omega$ further in the framework of quark delocalization color screening model and chiral quark model. We have shown $N\Omega$ is a narrow resonance in $\Lambda\Xi$ D-wave scattering before. However, the $\Lambda$-$\Xi$ scattering data analysis is quite complicated. Here we calculate the low-energy $N\Omega$ scattering phase shifts, scattering length, effective range and binding energy to provide another approach of STAR data analysis. Our results show there exists an $N\Omega$ "bound" state, which can be observed by the $N$-$\Omega$ correlation analysis with RHIC and LHC data, or by the new developed automatic scanning system at J-PARC. Besides, we also find that the hidden color channel-coupling is important for the $N\Omega$ system to develop intermediate-range attraction.Comment: 7 pages, 2 figure