An Interacting Two-Fluid Scenario for Quintom Dark Energy

The Quintom dark energy is a proposal that explains the recent observations that mildly favor the equation of state of dark energy ω crossing -1 near the past. The Quintom model is often constructed by two scalar fields, where one is the quintessence feld and another is the phantom field. The cosmological implication of the coupling of the two fields of the dark energy is out of question worth investigating. However, the consideration of the coupling in the field scenario is somewhat complex thus we propose an interacting two-fluid Quintom scenario for simplicity. The interaction between the two components is parametrized by a constant 71 in this scenario. The cosmological implications of this parametrization are investigated in detail in this paper. Also, a diagnostic for this model is performed by using the statefinder pairs {s, r} and {q, r}.     

Reply to Comments on ‘Five-Dimensional Cosmological Model with Variable G and A＇

The results of ours are correct. There are misprints in the sign of Eq. （11） and the factor （n - 1） in Eq. （12） in our paper [Chin. Phys. Lett. 24 （2007） 2185]. We did not study special values of n = 1 and n = -3.     

负能量简介

负能量(Negative Energy)意味着负质量.第一位探讨负物质的科学家就是稳恒态宇宙论的创始人之一英国天文学家邦迪(H.Bendi).他在1957年就证明了:负物质以一个恒定的不断增加的速度追逐正物质的概念是与广义相对论一致的.     

博广真美,奇人奇书--评秦克诚所著《邮票上的物理学史》

一本四百六十多页的大书摆在面前,随便翻看,首先映入眼帘的是一张又一张精美的彩色邮票,似乎是一本精美的集邮书.仔细读下去,全书66个题目,说的全是物理学的历史、物理学的事件和物理学的人物.从古希腊认为“万物源于水”的自然哲学家泰勒斯、中世纪的“光学之父”伊本·海塞姆,一直到量子力学的创始人、相对论的提出者和现代宇宙论的奠基人,古今数千年物理学从幼稚期到成熟期发展的历史,物理学各分支学科和交叉学科的基本内容,纵横五大洲各民族涌现出的优秀物理学家的贡献,都被作者用简洁生动的语言充分表述,引人入胜.物理学的各种规律是如…     

Dynamical Attractor of Modified Chaplygin Gas

The dynamical attractor of the modified Chaplygin gas （MCG） model is studied. The dynamical analysis indicates that the phase ωMCG = -1 is a dynamical attractor and the equation of state of the MCG approaches it from either ωMCG 〉 -1 or ωMCG 〈 -1, independent of the choice of its initial density parameter and the ratio of pressure to critical energy density. Therefore our universe will not end up with Big Rip in the future. Moreover, the evolutions of the density parameters Ωγ and ΩMCG are quite different. For different initial values of x and y, Ωγ decreases and ΩMCG increases as time increases, and they will eventually approach Ωe = 0 and ΩMCG = 1, i.e., de Sitter phase. This implies that when there is not the interaction （i.e., the energy transfer） between the barotropic background fluid and modified Chaplygin gas （MCG）, the behaviour of the MCG will be similar to ACDM in the future.     

宇宙弦的次级效应

本文给出了作为宇宙弦次级效应的宇宙再电离及大尺度结构形成的图象。计算表明,对于大统一宇宙弦作为种子的情况,可以实现所观测到的宇宙的高度再电离及星系分布的大尺度胞腔结构。对于通常所选的参数,此图象是合理和不可避免的。     

Exact Solutions for String Cosmology

Some more general cosmological solutions of Bianchi types Ⅱ，Ⅷ，and IX for a cloud string are presented.The physical implications of the solutions are briefly discussed.Our solutions include some of results previously given in the literature as special cases.     

霍金与量子宇宙论

 一、霍金---宇宙之迷的探索者史蒂芬·霍金1942年1月8日出生于英国的牛津,那一天刚好是伽利略逝世300周年纪念日。童年的霍金热衷于搞清楚一切事情的来龙去脉,他看到一件新奇的东西时总喜欢把它拆开,把每个零件的结构都弄明白---不过他往往很难再把它装回原样,因为他的手远不如头脑那样灵活,甚至写出来的字在班上也是出名的潦草。10岁时他喜欢做模型飞机和轮船,喜欢设计复杂的游戏。13岁左右就下决心将来要研究物理学和天文学。1959年他考到了自然科学的奖学金,顺利入读牛津大学,1962年去剑桥大学攻读博士学位,研究宇宙学。     

Jordan—Brans—Dick—Kaluza—Klein宇宙论的一支严格解

本文得到了带∧_(φ)和V_(φ)的 JBDKK 宇宙论在流形 S_1×M_a×M_D 上的一系列新的严格解,进而讨论了它们的某些进化性质.