Heavy flavor Production and Interactions in Relativistic Heavy-Ion Collisions in CMS Experiment

This paper presents the CMS measurements of quarkonia and open heavy flavor production in \pp, \pPb, and \PbPb collisions at \sqrtsnn = 2.76 and 5.02 TeV. A brief outlook of the near-future CMS heavy flavor physics analyses is provided at the end.Comment: SQM2016 conference proceedings on the CMS heavy flavor productio

Mask-CNN: Localizing Parts and Selecting Descriptors for Fine-Grained Image Recognition

Fine-grained image recognition is a challenging computer vision problem, due to the small inter-class variations caused by highly similar subordinate categories, and the large intra-class variations in poses, scales and rotations. In this paper, we propose a novel end-to-end Mask-CNN model without the fully connected layers for fine-grained recognition. Based on the part annotations of fine-grained images, the proposed model consists of a fully convolutional network to both locate the discriminative parts (e.g., head and torso), and more importantly generate object/part masks for selecting useful and meaningful convolutional descriptors. After that, a four-stream Mask-CNN model is built for aggregating the selected object- and part-level descriptors simultaneously. The proposed Mask-CNN model has the smallest number of parameters, lowest feature dimensionality and highest recognition accuracy when compared with state-of-the-arts fine-grained approaches.Comment: Submitted to NIPS 201

A MAD Explanation for the Correlation between Bulk Lorentz Factor and Minimum Variability Timescale

We offer an explanation for the anti-correlation between the minimum variability timescale ($MTS$) in the prompt emission light curve of gamma-ray bursts (GRBs) and the estimated bulk Lorentz factor of these GRBs, in the context of a magnetically arrested disk (MAD) model. In particular, we show that previously derived limits on the maximum available energy per baryon in a Blandford-Znajek jet leads to a relationship between the characteristic MAD timescale, $t_{MAD}$, in GRBs and the maximum bulk Lorentz factor: $t_{MAD} \propto \Gamma^{-6}$, somewhat steeper than (although within the error bars of) the fitted relationship found in the GRB data. Similarly, the MAD model also naturally accounts for the observed anti-correlation between $MTS$ and gamma-ray luminosity $L$ in the GRB data, and we estimate the accretion rates of the GRB disks (given these luminosities) in the context of this model. Both of these correlations ($MTS-\Gamma$ and $MTS-L$) are also observed in the AGN data, and we discuss the implications of our results in the context of both GRB and blazar systems

Enhancing the detection probability of single waveguided-photon by cavity technique

The resonant-cavity-enhanced (RCE) technique is an important approach to increasing the detection efficiency (DE) of typical free-space coupling photons. Here, we show that such a technique can also be utilized to increase the detection probability (DP) of a single waveguide-coupled photon. Based on a fully quantum mechanical theory in real space, we exactly calculated the absorption probability of a single photon for a two-level detector next to the waveguide. We find that the DP of the waveguide photon for the detector in a waveguide-coupled ring cavity is significantly higher than that for the bare detector directly coupled to the photon. Physically, the DP of the photon for the bare detector next to the waveguide is always limited by the finite transmission and reflection probabilities of the photon. The cavity technique is used to store the photon and thus increase its DP. The feasibility of the proposal with current integrated optical devices is then discussed

Coulomb-modified Fano interference in a double quantum dot Aharonov-Bohm ring

In this paper, the Coulomb-induced changes of Fano interference in electronic transport through a double quantum dot Aharonov-Bohm ring are discussed. It is found that the Coulomb interaction in the quantum dot in the reference channel can remarkably modify the Fano interference, including the increase or decrease of the symmetry of the Fano lineshape, as well as the inversion of the Fano lineshape, which is dependent on the appropriate strength of the Coulomb interaction. %But the nonzero Coulomb interaction %only leads to the emergence of two-group Fano lineshapes. When both the quantum dot levels are adjustable, the Coulomb-induced splitting of the nonresonant channel leads to the destruction of the Fano interference; whereas two blurry Fano lineshapes may appear in the conductance spectra when the many-body effect in the dot of the resonant channel is also considered. Interestingly, in the absence of magnetic field, when the different-strength electron interactions make one pair of levels of the dots in different channels the same, the corresponding resonant state keeps vacuum despite the adjustment of quantum dot levels.Comment: 11 pages, 6 figure

Perturbation Analysis and Randomized Algorithms for Large-Scale Total Least Squares Problems

In this paper, we present perturbation analysis and randomized algorithms for the total least squares (TLS) problems. We derive the perturbation bound and check its sharpness by numerical experiments. Motivated by the recently popular probabilistic algorithms for low-rank approximations, we develop randomized algorithms for the TLS and the truncated total least squares (TTLS) solutions of large-scale discrete ill-posed problems, which can greatly reduce the computational time and still keep good accuracy.Comment: 27 pages, 10 figures, 8 table

Blowup solutions of Grushin's operator

In this note, we consider the blowup phenomenon of Grushin's operator. By using the knowledge of probability, we first get expression of heat kernel of Grushin's operator. Then by using the properties of heat kernel and suitable auxiliary function, we get that the solutions will blow up in finite time.Comment:

Converse bounds for classical communication over quantum networks

We explore the classical communication over quantum channels with one sender and two receivers, or with two senders and one receiver, First, for the quantum broadcast channel (QBC) and the quantum multi-access channel (QMAC), we study the classical communication assisted by non-signalling and positive-partial-transpose-preserving codes, and obtain efficiently computable one-shot bounds to assess the performance of classical communication. Second, we consider the asymptotic communication capability of communication over the QBC and QMAC. We derive an efficiently computable strong converse bound for the capacity region, which behaves better than the previous semidefinite programming strong converse bound for point-to-point channels. Third, we obtain a converse bound on the one-shot capacity region based on the hypothesis testing divergence between the given channel and a certain class of subchannels. As applications, we analyze the communication performance for some basic network channels, including the classical broadcast channels and a specific class of quantum broadcast channels.Comment: 18 pages, 5 figures, comments are welcom

A multilevel correction method for optimal controls of elliptic equation

We propose in this paper a multilevel correction method to solve optimal control problems constrained by elliptic equations with the finite element method. In this scheme, solving optimization problem on the finest finite element space is transformed to a series of solutions of linear boundary value problems by the multigrid method on multilevel meshes and a series of solutions of optimization problems on the coarsest finite element space. Our proposed scheme, instead of solving a large scale optimization problem in the finest finite element space, solves only a series of linear boundary value problems and the optimization problems in a very low dimensional finite element space, and thus can improve the overall efficiency for the solution of optimal control problems governed by PDEs

A Theoretical Framework for Bayesian Nonparametric Regression

We develop a unifying framework for Bayesian nonparametric regression to study the rates of contraction with respect to the integrated $L_2$-distance without assuming the regression function space to be uniformly bounded. The framework is very flexible and can be applied to a wide class of nonparametric prior models. Three non-trivial applications of the proposed framework are provided: The finite random series regression of an $\alpha$-H\"older function, with adaptive rates of contraction up to a logarithmic factor; The un-modified block prior regression of an $\alpha$-Sobolev function, with adaptive-and-exact rates of contraction; The Gaussian spline regression of an $\alpha$-H\"older function, with the near-optimal posterior contraction. These applications serve as generalization or complement of their respective results in the literature. Extensions to the fixed-design regression problem and sparse additive models in high dimensions are discussed as well