The case for the cosmological constant

Pramana

Varun Sahni¹ 

[1] Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007, India$$

关键词: Cosmology;    supernovae;    cosmic microwave background;    cosmological constant;    vacuum fluctuations.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

I present a short overview of current observational results and theoretical models for a cosmological constant. The main motivation for invoking a small cosmological constant (or 𝛬-term) at the present epoch has to do with observations of high redshift Type Ia supernovae which suggest an accelerating universe. A flat accelerating universe is strongly favoured by combining supernovae observations with observations of CMB anisotropies on degree scales which give the `best-fit’ values 𝛺𝛬 ≃ 0.7 and 𝛺m ≃ 0.3. A time dependent cosmological 𝛬-term can be generated by scalar field models with exponential and power law potentials. Some of these models can alleviate the `fine tuning’ problem which faces the cosmological constant.

【 授权许可】

Unknown