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1. chinaXiv:201709.00120 [pdf]

贝叶斯因子及其在JASP中的实现

胡传鹏; 孔祥祯; Eric-Jan Wagenmakers; Alexander Ly; 彭凯平
分类: 心理学 >> 心理统计

统计推断在科学研究中起到关键作用,然而当前科研中最常用的经典统计方法——零假设检验(Null hypothesis significance test, NHST)却因为难以正确理解而被滥用或误用。有研究者提出使用贝叶斯因子(Bayes factor)作为是一种替代和(或)补充的统计方法。贝叶斯因子是贝叶斯统计中用来进行模型比较和假设检验的重要方法,这一方法对于心理学及相关领域的大部分研究者来说仍然比较陌生。因此,本文介绍了贝叶斯因子的基本思路,并总结了贝叶斯因子与NHST相比的优势。在此基础上,以贝叶斯独立样本t检验为例,演示如何在开放的统计软件JASP中实现贝叶斯因子的计算,并解释了对贝叶斯因子结果的解读。最后,对贝叶斯因子的不足及其应用价值进行了讨论。

提交时间: 2017-09-27 点击量3864下载量1375 评论 0

2. chinaXiv:201709.00123 [pdf]

Inflationary Attractor in Braneworld Scenario

Zong-Kuan Guo; Hong-Sheng Zhang; Yuan-Zhong Zhang
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

We demonstrate the attractor behavior of inflation driven by a scalar field or a tachyon field in the context of recently proposed four-dimensional effective gravity induced on the world-volume of a three-brane in five-dimensional Einstein gravity, and we obtain a set of exact inflationary solutions.Phase portraits indicate that an initial kinetic term decays rapidly and it does not prevent the onset of inflation. The trajectories more rapidly reach the slow rolling curve in braneworld scenario than in the standard cosmology.

提交时间: 2017-09-27 点击量454下载量229 评论 0

3. chinaXiv:201709.00124 [pdf]

Inflection point inflation and dark energy in supergravity

Tie-Jun Gao; Zong-Kuan Guo
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

We consider an inflection point inflationary model in supergravity with a single chiral superfield and show that the predicted values of the scalar spectral index and tensor-to-scalar ratio are consistent with the Planck 2015 results. In this model supersymmetry is strongly broken after inflation, which results in a non-SUSY de-Sitter vacuum responsible for the recent accelerated expansion of the Universe.

提交时间: 2017-09-27 点击量429下载量210 评论 0

4. chinaXiv:201709.00125 [pdf]

Black Holes in the Dilatonic Einstein-Gauss-Bonnet Theory in Various Dimensions II– Asymptotically AdS Topological Black Holes –

Zong-Kuan GUO; Nobuyoshi Ohta; Takashi Torii
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

We study asymptotically AdS topological black hole solutions with k = 0 (plane symmetric) in the Einstein gravity with Gauss-Bonnet term, the dilaton and a “cosmo-logical constant” in various dimensions. We derive the field equations for suitable ansatz for general D dimensions. We determine the parameter regions including dilaton cou-plings where such solutions exist and construct black hole solutions of various masses numerically in D = 4, 5, 6 and 10 dimensional spacetime with (D − 2)-dimensional hypersurface of zero curvature.

提交时间: 2017-09-27 点击量454下载量224 评论 0

5. chinaXiv:201709.00126 [pdf]

Accelerating Cosmologies in theEinstein-Gauss-Bonnet Theory with Dilaton

Kazuharu BAMBA; Zong-Kuan Guo; Nobuyoshi Ohta
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

We study cosmological solutions in the low-energy effective heterotic string theory, which is the Einstein gravity with Gauss-Bonnet term and the dilaton. We show that the field equations are cast into an autonomous system for flat internal and external spaces, and derive all the fixed points in the system. We also examine the time evolution of the solutions and whether the solutions can give (transient) accelerated expansion of our four-dimensional space in the Einstein frame.

提交时间: 2017-09-27 点击量194下载量41 评论 0

6. chinaXiv:201709.00127 [pdf]

Probing the Coupling between Dark Components of the Universe

Zong-Kuan Guo; Nobuyoshi Ohta; Shinji Tsujikawa
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

We place observational constraints on a coupling between dark energy and dark matter by using 71 Type Ia supernovae (SNe Ia) from the first year of the five-year Supernova Legacy Survey (SNLS), the cosmic microwave background (CMB) shift parameter from the three-year Wilkinson Microwave Anisotropy Probe (WMAP), and the baryon acoustic oscillation (BAO) peak found in the Sloan Digital Sky Survey (SDSS). The interactions we study are (i) constant coupling #14; and (ii) varying coupling #14;(z) that depends on a redshift z, both of which have simple parametrizations of the Hubble parameter to confront with observational data. We find that the combination of the three databases marginalized over a present dark energy density gives stringent constraints on the coupling,−0.08 < #14; < 0.03 (95% CL) in the constant coupling model and −0.4 < #14;0 < 0.1 (95% CL) in the varying coupling model, where #14;0 is a present value. The uncoupled #3;CDM model (wX = −1 and #14; = 0) still remains a good fit to the data, but the negative coupling (#14; < 0) with the equation of state of dark energy wX < −1 is slightly favoured over the #3;CDM model.

提交时间: 2017-09-27 点击量400下载量44 评论 0

7. chinaXiv:201709.00128 [pdf]

Realizing Scale-invariant Density Perturbations in Low-energy Effective String Theory

Zong-Kuan Guo; Nobuyoshi Ohta; Shinji Tsujikawa
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

We discuss the realization of inflation and resulting cosmological perturbations in the low-energy effective string theory. In order to obtain nearly scale-invariant spectra of density perturbations and a suppressed tensor-to-scalar ratio, it is generally necessary that the dilaton field #30; is effectively decoupled from gravity together with the existence of a slowly varying dilaton potential. We also study the effect of second-order corrections to the tree-level action which are the sum of a Gauss-Bonnet term coupled to #30; and a kinetic term (∇#30;)4. We find that it is possible to realize observationally supported spectra of scalar and tensor perturbations provided that the correction is dominated by the (∇#30;)4 term even in the absence of the dilaton potential. When the Gauss-Bonnet term is dominant, tensor perturbations exhibit violent negative instabilities on small-scales about a de Sitter background in spite of the fact that scale-invariant scalar perturbations can be achieved.

提交时间: 2017-09-27 点击量230下载量70 评论 0

8. chinaXiv:201709.00129 [pdf]

Two-Field Quintom Models in the w − w Plane

Zong-Kuan Guo; Yun-Song Piao; Xinmin Zhang; Yuan-Zhong Zhang
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

The w−w′ plane, defined by the equation of state parameter for the dark energy and its derivative with respect to the logarithm of the scale factor, is useful to the study of classifying the dynamical dark energy models. In this note, we examine the evolving behavior of the two-field quintom models with w crossing the w = −1 barrier in the w − w′ plane. We find that these models can be divided into two categories, type A quintom in which w changes from > −1 to < −1 and type B quintom in which w changes from < −1 to > −1 as the universe expands.

提交时间: 2017-09-27 点击量1737下载量1015 评论 0

9. chinaXiv:201709.00130 [pdf]

Constraints on the DGP Model from Recent Supernova Observations and Baryon Acoustic Oscillations

Zong-Kuan Guo , Zong-Hong Zhu , J.S. Alcaniz , Yuan-Zhong Zhang; Zong-Hong Zhu; J.S. Alcaniz; Yuan-Zhong Zhang
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

Although there is mounting observational evidence that the expansion of our universe is undergoing a late-time acceleration, the mechanism for this acceleration is yet unknown. In the so-called Dvali-Gabadadze-Porrati (DGP) model this phenomena is attributed to gravitational leakage into extra dimensions. In this work, we mainly focus our attention to the constraints on the model from the gold sample of type Ia supernovae (SNeIa), the first year data from the Supernova Legacy Survey (SNLS) and the baryon acoustic oscillation (BAO) peak found in the Sloan Digital Sky Survey (SDSS). At 99.73% confidence level, the combination of the three databases provides m = 0.270+0.018−0.017 and rc = 0.216+0.012−0.013 (hence a spatially closed universe with k = −0.350+0.080−0.083), which seems to be in contradiction with the most recent WMAP results indicating a flat universe. Based on this result, we also estimated the transition redshift (at which the universe switches from deceleration to acceleration) to be 0.70 < zq=0 < 1.01, at 2#27;confidence level.

提交时间: 2017-09-27 点击量194下载量40 评论 0

10. chinaXiv:201709.00131 [pdf]

A Tracker Solution for a Holographic Dark Energy Model

Hui Li,b; Zong-Kuan Guo; Yuan-Zhong Zhang
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等

We investigate a kind of holographic dark energy model with the future event horizon the IR cutoff and the equation of state −1. In this model, the constraint on the equation of state automatically specifies an interaction between matter and dark energy. With this interaction included, an accelerating expansion is obtained as well as the transition from deceleration to acceleration. It is found that there exists a stable tracker solution for the numerical parameter d > 1, and d smaller than one will not lead to a physical solution. This model provides another possible phenomenological framework to alleviate the cosmological coincidence problem in the context of holographic dark energy. Some properties of the evolution which are relevant to cosmological parameters are also discussed.

提交时间: 2017-09-27 点击量421下载量29 评论 0

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