Exploring the Energy Sources Powering the Light Curve of the Type Ibn Supernova PS15dpn and the Mass-Loss History of the SN Progenitor

PS15dpn is a luminous rapidly rising Type Ibn supernova (SN) discovered by Pan-STARRS1 (PS1). Previous study showed that its bolometric light curve (LC) cannot be explained by the $^{56}$Ni model. In this paper, we used the $^{56}$Ni model, the magnetar model, the circumstellar interaction (CSI) model, and the CSI plus $^{56}$Ni model to fit the bolometric LC of PS15dpn. We found that the $^{56}$Ni model can fit the bolometric LC but the parameters are unrealistic, and that the magnetar model, the CSI model, and the CSI plus $^{56}$Ni model can match the data with reasonable parameters. Considering the facts that the emission lines indicative of the interaction between the ejecta and the CSM have been confirmed, and that the SNe produced by the explosions of massive stars can synthesize moderate amount of $^{56}$Ni, we suggest that the CSI plus $^{56}$Ni model is the most promising. Assuming that the CSM is a shell (wind), the masses of the ejecta, the CSM, and the $^{56}$Ni are $15.79_{-4.77}^{+5.44}$ M$_\odot$ ($14.18_{-1.64}^{+1.81}$ M$_\odot$), $0.84_{-0.10}^{+0.13}$ M$_\odot$ ($0.88_{-0.12}^{+0.11}$ M$_\odot$), and $0.32_{-0.11}^{+0.11}$ M$_\odot$ ($0.16_{-0.08}^{+0.13}$ M$_\odot$), respectively. The inferred ejecta masses are consistent with the scenario that the progenitors of SNe Ibn are massive Wolf-Rayet stars. Adopting the shell CSM scenario, the shell might be expelled by an eruption of the progenitor just $\sim$ 17$-$167 days prior to the SN explosion; for the wind scenario, the inferred mass-loss rate of the wind is $\sim 8.0$ M$_\odot$ yr$^{-1}$, indicating that the wind is a "super-wind" having extreme high mass-loss rate.Comment: 19 pages, 11 figures, 4 tables, accepted for publication in Ap

Isobaric Yield Ratio Difference in Heavy-ion Collisions, and Comparison to Isoscaling

An isobaric yield ratio difference (IBD) method is proposed to study the ratio of the difference between the chemical potential of neutron and proton to temperature ($\Delta\mu/T$) in heavy-ion collisions. The $\Delta\mu/T$ determined by the IBD method (IB-$\Delta\mu/T$) is compared to the results of the isoscaling method (IS-$\Delta\mu/T$), which uses the isotopic or the isotonic yield ratio. Similar distributions of the IB- and IS-$\Delta\mu/T$ are found in the measured 140$A$ MeV $^{40,48}$Ca + $^{9}$Be and the $^{58,64}$Ni + $^{9}$Be reactions. The IB- and IS-$\Delta\mu/T$ both have a distribution with a plateau in the small mass fragments plus an increasing part in the fragments of relatively larger mass. The IB- and IS-$\Delta\mu/T$ plateaus show dependence on the $n/p$ ratio of the projectile. It is suggested that the height of the plateau is decided by the difference between the neutron density ($\rho_n$) and the proton density ($\rho_p$) distributions of the projectiles, and the width shows the overlapping volume of the projectiles in which $\rho_n$ and $\rho_p$ change very little. The difference between the IB- and IS-$\Delta\mu/T$ is explained by the isoscaling parameters being constrained by the many isotopes and isotones, while the IBD method only uses the yields of two isobars. It is suggested that the IB-$\Delta\mu/T$ is more reasonable than the IS-$\Delta\mu/T$, especially when the isotopic or isotonic ratio disobeys the isoscaling. As to the question whether the $\Delta\mu/T$ depends on the density or the temperature, the density dependence is preferred since the low density can result in low temperature in the peripheral reactions.Comment: 6 pages, 6 figures, mistake of reference correcte

Chemical Property of Colliding Sources in 124,136Xe and 112,124Sn Induced Collisions in Isobaric Ratio Difference and Isoscaling Methods

The isoscaling and isobaric ratio difference (IBD) methods are used to study the $\Delta\mu/T$ ($\Delta\mu$ being the difference between the chemical potentials of neutron and proton, and $T$ being the temperature) in the measured 1$A$ GeV $^{124}$Sn + $^{124}$Sn, $^{112}$Sn + $^{112}$Sn, $^{136}$Xe + Pb and $^{124}$Xe + Pb reactions. The isoscaling phenomena in the $^{124}$Sn/$^{112}$Sn and the $^{136}$Xe/$^{124}$Xe reactions pairs are investigated, and the isoscaling parameter $\alpha$ and $\beta$ are obtained. The $\Delta\mu/T$ determined by the isoscaling method (IS--$\Delta\mu/T$) and IBD method (IB--$\Delta\mu/T$) in the measured Sn and Xe reactions are compared. It is shown that in most of fragments, the IS-- and IB-- $\Delta\mu/T$ are consistent in the Xe reactions, while the IS-- and IB-- $\Delta\mu/T$ are only similar in the less neutron-rich fragments in the Sn reactions. The shell effects in IB--$\Delta\mu/T$ are also discussed.Comment: 5 figures, submitted to J. Phys. G: Nucl. Part. Phy

Weak measurement amplification based on thermal noise effect

Most studies for postselected weak measurement focus on using pure Gaussian state as a pointer, which can only give an amplification limit reaching the level of the ground state fluctuation. When the pointer is initialised in a thermal state, we find that the amplification limit after the postselection can reach the level of thermal fluctuation, indicating that the amplification effect achieving the level of thermal fluctuation is also increased with the temperature grow, and also give the amplification mechanism different from the one with pure Gaussian state pointer. To illustrate these results, we propose two schemes to implement room temperature amplification of the mechanical oscillator's displacement caused by a single photon in optomechanical system. The two schemes can both enhance the mechanical oscillator's original displacement by nearly seven orders of magnitude, attaining sensitivity to displacements of $0.26$ nm. Such amplification effect can be used to observe the impact of a single photon on a room temperature mechanical oscillator which is hard to detect in traditional measurement.Comment: 9 figure

Amplification effects in optomechanics via weak measurement

We revisit the scheme of single-photon weak-coupling optomechanics using post-selection, proposed by Pepper, Ghobadi, Jeffrey, Simon and Bouwmeester [Phys. Rev. Lett. 109, 023601 (2012)], by analyzing the exact solution of the dynamical evolution. Positive and negative amplification effects of the displacement of the mirror's position can be generated when the Kerr phase is considered. This effect occurs when the post-selected state of the photon is orthogonal to the initial state, which can not be explained by the usual weak measurement results. The amplification effect can be further modulated by a phase shifter, and the maximal displacement state can appear within a short evolution time

On the index of unbalanced signed bicyclic graphs

In this paper, we focus on the index ( largest eigenvalue) of the adjacency matrix of connected signed graphs. We give some general results on the index when the corresponding signed graph is perturbed. As applications, we determine the first five largest index among all unbalanced bicyclic graphs on n >= 36 vertices together with the corresponding extremal signed graphs whose index attain these values.Comment: 14 pages, 6 figure

Reinvestigation of the electron fraction and electron Fermi energy of neutron star

In this work, we reinvestigate the electron fraction $Y_{e}$ and electron Fermi energy $E_{F}(e)$ of neutron stars, based on our previous work of Li et al.(2016), in which we firstly deduced a special solution to $E_{F}(e)$, and then obtained several useful analytical formulae for $Y_{\rm e}$ and matter density $\rho$ within classical models and the relativistic mean field(RMF) theory using numerically fitting. The advantages of this work include the following aspects:(1) The linear functions are substituted for the nonlinear exponential functions used in the previous work. This method may be more simple, and closer to realistic equation of state\,(EoS) of a neutron star(NS), because there are linear or quasi-linear relationships between number fractions of leptons and matter density, which can be seen by solving NS EoS; (2)we introduce a dimensionless variable $\varrho$\,($\varrho=\rho/\rho_0$, $\rho_{0}$ is the standard saturated nuclear density), which greatly reduces the scope of the fitting coefficients;(3)we present numerical errors including absolute and relative deviations between the data and fit. By numerically simulating, we have obtained several analytical formulae for $Y_{e}$ and $\rho$ for both APR98 and RMF models. Combining these analytical formulae with the special solution, we can calculate the value of $E_{\rm F}(e)$ for any given matter density. Since $Y_e$ and $E_{ F}(e)$ are important in assessing cooling rate of a NS and the possibility of kaon/pion condensation in the NS interior, this study could be useful in the future study on the thermal evolution of a NS.Comment: 3 figures, 3 tables , and We welcome any comment you might have about the content, To be published in Astron. Nach

Discovering Interesting Plots in Production Yield Data Analytics

An analytic process is iterative between two agents, an analyst and an analytic toolbox. Each iteration comprises three main steps: preparing a dataset, running an analytic tool, and evaluating the result, where dataset preparation and result evaluation, conducted by the analyst, are largely domain-knowledge driven. In this work, the focus is on automating the result evaluation step. The underlying problem is to identify plots that are deemed interesting by an analyst. We propose a methodology to learn such analyst's intent based on Generative Adversarial Networks (GANs) and demonstrate its applications in the context of production yield optimization using data collected from several product lines

The Dipole Magnetic Field and Spin-down Evolutions of The High Braking Index Pulsar PSR J1640-4631

In this work, we interpreted the high braking index of PSR J1640$-$4631 with a combination of the magneto-dipole radiation and dipole magnetic field decay models. By introducing a mean rotation energy conversion coefficient $\overline{\zeta}$, the ratio of the total high-energy photon energy to the total rotation energy loss in the whole life of the pulsar, and combining the pulsar's high-energy and timing observations with reliable nuclear equation of state, we estimate the pulsar's initial spin period, $P_{0}\sim (17-44)$ ms, corresponding to the moment of inertia $I\sim (0.8-2.1)\times 10^{45}$ g cm$^{2}$. Assuming that PSR J1640$-$4631 has experienced a long-term exponential decay of the dipole magnetic field, we calculate the true age $t_{\rm age}$, the effective magnetic field decay timescale $\tau_{D}$, and the initial surface dipole magnetic field at the pole $B_{p}(0)$ of the pulsar to be $(2900-3100)$ yrs, $1.07(2)\times10^{5}$ yrs, and $(1.84-4.20)\times10^{13}$ G, respectively. The measured braking index of $n=3.15(3)$ for PSR J1640$-$4631 is attributed to its long-term dipole magnetic field decay and a low magnetic field decay rate, $dB_{\rm p}/dt\sim -(1.66-3.85)\times10^{8}$ G yr$^{-1}$. Our model can be applied to both the high braking index ($n>3$) and low braking index ($n<3$) pulsars, tested by the future polarization, timing, and high-energy observations of PSR J1640$-$4631.Comment: Correspoding to the publication version: 2017, ApJ, 849, 19 (12pp

Fermi Surfaces and Analytic Green's Functions from Conformal Gravity

We construct T^2-symmetric charged AdS black holes in conformal gravity. The most general solution up to an overall conformal factor contains three non-trivial parameters: the mass, electric charge and a quantity that can be identified as the massive spin-2 hair. We study the Dirac equation for the charged massless spinor in this background. The equation can be solved in terms of the general Heun's function for generic frequency \omega and wave number k. This allows us to obtain the analytic Green's function G(\omega, k) for both extremal and non-extremal black holes. For some special choice of back hole parameters, we find that the Green's function reduces to simpler hypergeometric or confluent hypergeometric functions. We study the Fermi surfaces associated with the poles of the Green's function with vanishing \omega. We find examples where the Fermi surfaces for non-Fermi liquids as well as the characteristic Fermi ones can arise. We illustrate the non-trivial differences in the Green's function and Fermi surfaces between the extremal and non-extremal black holes.Comment: 46 pages, 13 figures, typoes corrected and references added. Further discussions on the AdS/CFT correspondence in conformal gravity and the infrared contribution to the Green's function in extremal and non-extremal charged black holes were adde