Shell Collision Induced Kilo-Hertz Quasi-Periodic Oscillation in X-Ray Binaries

Twin kilo-Hertz Quasi-periodic oscillation with ratio 3/2 has been found in some compact sources, which is believed to be related with their innermost regions of accretion disks, and hence carrying information of gravity in strong regime. However, more complicated phenomena have been revealed, e.g., the twin kilo-Hertz Quasi-periodic oscillation of 4U 1820-20 start increasing at certain spectral state and then saturate upon reaching certain level. Moreover, such quasi-periodic oscillation is not uniform and has multiple peaks, which displays random feature. This letter suggests that these challenges could be easy to understand if the quasi-periodic oscillation originates in jets of compact objects. With a seed periodicity originating in either neutron star spin or accretion, shell collision develops in jet. The corresponding twin kilo-Hertz quasi-periodic oscillations automatically carry random feature, vary in frequency; and couple with luminosity, spectral properties, which well account for the observation of 4U 1820-30. New quasi-periodic oscillation of 4U 1820-30 is predicted, which can test the validity of this model. And the scenario is applicable to other compact object like AGN.Comment: 5pages, 3figure

Mathematical Foundations for Information Theory in Diffusion-Based Molecular Communications

Molecular communication emerges as a promising communication paradigm for nanotechnology. However, solid mathematical foundations for information-theoretic analysis of molecular communication have not yet been built. In particular, no one has ever proven that the channel coding theorem applies for molecular communication, and no relationship between information rate capacity (maximum mutual information) and code rate capacity (supremum achievable code rate) has been established. In this paper, we focus on a major subclass of molecular communication - the diffusion-based molecular communication. We provide solid mathematical foundations for information theory in diffusion-based molecular communication by creating a general diffusion-based molecular channel model in measure-theoretic form and prove its channel coding theorems. Various equivalence relationships between statistical and operational definitions of channel capacity are also established, including the most classic information rate capacity and code rate capacity. As byproducts, we have shown that the diffusion-based molecular channel is with "asymptotically decreasing input memory and anticipation" and "d-continuous". Other properties of diffusion-based molecular channel such as stationarity or ergodicity are also proven

Vector mesons and electromagnetic form factor of the Λ\Lambda hyperon

The measured electromagnetic form factors of $\Lambda$ hyperon in the time-like region are significantly deviated from pQCD prediction. We attribute the non-vanishing cross section near threshold to be the contribution of below-threshold $\phi$(2170) state, supporting its exotic structure. Above the threshold, we find significant role of a wide vector meson with the mass of around 2.34 GeV, which would be the same state present in $p\bar{p}$ annihilation reactions. As a result, we give a satisfactory description of the behavior of existing data without modifying pQCD expectation.Comment: 10 pages, 1 figure, published versio

Exclusive J/ψJ/\psi Production in Diffractive Process with AdS/QCD Holographic Wave Function in BLFQ

The AdS/QCD holographic wave function of basis light-front quantization (BLFQ) for vector meson $J/\psi$ is applied in this manuscript. The exclusive production of $J/\psi$ in diffractive process is computed in dipole model with AdS/QCD holographic wave function. We use IP-Sat and IIM model in the calculation of the differential cross section of the dipole scattering off the proton. The prediction of AdS/QCD holographic wave function in BLFQ gives a good agreement to the experimental data

Incoherent vector mesons production in PbPb ultraperipheral collisions at the LHC

Incoherent rapidity distributions of vector mesons are computed in dipole model in PbPb ultraperipheral collisions at the CERN Large Hadron Collider (LHC). The IIM model fitted from newer data is employed in the dipole amplitude. The Boosted Gaussian and Gaus-LC wave functions for vector mesons are implemented in the calculation as well. Predictions for the $J/\psi$, $\psi(2s)$, $\rho$ and $\phi$ incoherent rapidity distributions are evaluated and compared with experimental data and other theoretical predictions in this paper. We obtain closer predictions of the incoherent rapidity distributions for $J/\psi$ than previous calculations in the IIM model

Sudakov Factor in the Deep Inelastic Scattering of a Current off a Large Nucleus

We consider a gedanken experiment of the scattering of a current off a large nucleus to study the gluon saturation at the small-x limit and compute the Sudakov factor of this process through a one-loop calculation. The differential cross section is expressed in term of the Sudakov resummation, in which the collinear and the rapidity divergences are subtracted. We also discuss how to probe the Weizsaecker-Williams (WW) gluon distribution in the process of photon pair production in the pA collisions.Comment: 7 pages, 6 figure

The J/ψ J/\psi production in PbPb ultraperipheral collisions at sNN=2.76TeV\sqrt{s_{NN}}=2.76\mathrm{TeV}

We calculate the coherent and incoherent production of $J/\psi$ in PbPb ultraperipheral collisions. The production of $J/\psi$ in ultraperipheral collsions is product of photon flux distributions and cross section of photon-nucleus scatterings. The distributions of photon flux is computed in light-cone perturbation theory and the cross section of photon-nucleus scatterings is calculated in dipole model, we assume that the two gluons exchange contribution is the coherent cross section and the large-$N_c$ contribution is the incoherent cross section in photon-nucleus scattering. The numerical result of the rapidity distributions of $J/\psi$ production in PbPb ultraperipheral collisions at $\sqrt{s_{NN}}=2.76$TeV are compared with the experimental data measured by the ALICE collaboration

Photoproduction of vector mesons in proton-proton ultraperipheral collisions at the CERN Large Hadron Collider

Photoproduction of vector mesons are computed in dipole model in proton-proton ultraperipheral collisions(UPCs) at the CERN Large Hadron Collider (LHC). The dipole model framework is employed in the calculations of vector mesons production in diffractive processes. Parameters of the bCGC model are refitted with the latest inclusive deep inelastic scattering experimental data. Employing the bCGC model and Boosted Gaussian light-cone wave function for vector mesons, we obtain prediction of rapidity distributions of $J/\psi$ and $\psi(2s)$ mesons in proton-proton ultraperipheral collisions at the LHC. The predictions give a good description to the experimental data of LHCb. Predictions of $\phi$ and $\omega$ mesons are also evaluated in this paper.Comment: arXiv admin note: text overlap with arXiv:1805.0621

Photoproduction of charged final states in ultra-peripheral collisions and electroproduction at an electron-ion collider

Ultra-peripheral collisions (UPCs) of relativistic ions are an important tool for studying photoproduction at high energies. Vector meson photoproduction is an important tool for nuclear structure measurements and other applications. A future electron-ion collider (EIC) will allow additional studies, using virtual photons with a wide range of $Q^2$. We propose a significant expansion of the UPC and EIC photoproduction physics programs to include charged final states which may be produced via Reggeon exchange. We consider two examples: $a_2^+(1320)$, which is a conventional $q\overline q$ meson, and the exotic $Z_c^+(4430)$ state (modeled here as a tetraquark). The $Z_c^+(4430)$ cross-section depends on its internal structure, so photoproduction can test whether the $Z_c^+(4430)$ is a tetraquark or other exotic object. We calculate the rates and kinematic distributions for $\gamma p\rightarrow X^+n$ in $pA$ UPCs and $ep$ collisions at an EIC and in UPCs. The rates are large enough for detailed studies of these final states. Because the cross-section for Reggeon exchange is largest near threshold, the final state rapidity distribution depends on the beam energies. At high-energy colliders like the proposed LHeC or $pA$ collisions at the LHC, the final states are produced at far forward rapidities. For lower energy colliders, the systems are produced closer to mid-rapidity, within reach of central detectors.Comment: 5 pages with 3 figure

Finding Mixed Nash Equilibria of Generative Adversarial Networks

We reconsider the training objective of Generative Adversarial Networks (GANs) from the mixed Nash Equilibria (NE) perspective. Inspired by the classical prox methods, we develop a novel algorithmic framework for GANs via an infinite-dimensional two-player game and prove rigorous convergence rates to the mixed NE, resolving the longstanding problem that no provably convergent algorithm exists for general GANs. We then propose a principled procedure to reduce our novel prox methods to simple sampling routines, leading to practically efficient algorithms. Finally, we provide experimental evidence that our approach outperforms methods that seek pure strategy equilibria, such as SGD, Adam, and RMSProp, both in speed and quality