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Topics in Superstring Perturbation Theory and Non-equilibrium Field Theory at Finite Temperatures

有限温度下超弦微扰理论和非平衡场论专题

基本信息

批准号：
15540286
负责人：
AOKI Kenichiro
金额：
$ 1.34万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

项目摘要

With E. D'Hoker and D. P. Phong, we obtained analytically the two loop contribution to the cosmological constant in superstring theory, in some asymmetric orbifold vacua of physics interest. At the time, there were claims that this vacua had zero cosmological constant to all orders in perturbation theory, possibly leading to a hitherto unknown mechanism for preserving zero cosmological constant in spacetimes with no supersymmetry. This feature would be quite desirable from a phenomenological point of view. There was no clear statement on this issue, mostly due to the technical difficulties involved. Through explicit computation, we showed that in the relevant case, the cosmological constant is non-zero at the two loop level, contributing to the resolution of this issue. To date, there seems to be no systematic way of constructing asymmetric orbifolds. As a relevant related issue, we also systematically analyzed how to construct asymmetric orbifolds.Dynamics of non-equilibrium theories at finite temperatures is an important aspect of many fields in physics. However, there currently exist not that many quantitative results from first principles. With D. Kusnezov, H. Spohn and others, we have been computing the explicit behavior of physical quantities in non-equilibrium, from first principles. In particular, we have quantitatively shown how local equilibrium and linear response are broken under thermal gradients in some theories. Also, we elucidated the relationship between the microscopic aspects of the theory, such as Lyapunov exponents, and the macroscopic aspects of the theory, such as phase space dimensional loss and transport phenomena, under thermal gradients.The results mentioned above have been published in refereed journals and we are preparing some more publications on them. Furthermore, we believe that the results we have obtained will serve as the basis for further research.

用大肠D'Hoker和D. P.Phong的研究中，我们在超弦理论中，在一些物理学感兴趣的非对称轨道真空中，解析地得到了两圈对宇宙常数的贡献。当时，有人声称这个真空在微扰论中的所有阶次都是零宇宙常数，这可能导致了一种迄今为止未知的机制，可以在没有超对称的时空中保持零宇宙常数。从现象学的观点来看，这个特征是非常可取的。在这个问题上没有明确的声明，主要是由于所涉及的技术困难。通过显式计算，我们证明了在相关的情况下，宇宙常数在两圈水平上是非零的，有助于解决这个问题。到目前为止，似乎还没有系统的方法来构建不对称的orbifolds。作为一个相关的问题，我们还系统地分析了如何构造非对称轨道褶皱。有限温度下的非平衡理论动力学是物理学许多领域的一个重要方面。然而，目前还没有那么多的第一性原理的定量结果。与D.库斯涅佐夫Spohn和其他人，我们一直在计算非平衡态物理量的显式行为，从第一原理。特别是，我们已经定量地显示了如何打破局部平衡和线性响应下的温度梯度在一些理论。此外，我们阐明了理论的微观方面，如李雅普诺夫指数，和理论的宏观方面，如相空间的尺寸损失和输运现象，在热梯度下的关系。上述结果已经发表在参考期刊，我们正在准备一些更多的出版物。此外，我们相信我们所获得的结果将作为进一步研究的基础。