One of the major problems in cosmology today is to explain the observed acceleration of the universe. The present observational data are consistent with the simplest solution to this problem, which is based on the vacuum energy. A decaying vacuum energy is a very attractive solution. It could link the value of the present vacuum energy, that is accelerating the universe today, with the value that created the inflationary epoch in the past. We investigate here models that suggest that the vacuum energy decays into cold dark matter (CDM) and show that the density fluctuation spectrum obtained from the cosmic microwave background (CMB) data together with large galaxy surveys (e.g., the Sloan Digital Sky Survey), puts strong limits on the rate of decay of the vacuum energy. CDM produced by a decaying vacuum energy would dilute the density fluctuation spectrum, created in the primordial universe and observed with large galaxy surveys at low redshifts. Our results indicate that the decay rate of the vacuum energy into CDM is extremely small.
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机译：当今宇宙学的主要问题之一是解释观察到的宇宙加速。当前的观测数据与基于真空能量的最简单解决方案相一致。衰减的真空能量是非常有吸引力的解决方案。它可以将当前正在加速宇宙发展的真空能的价值与过去创造通货膨胀时代的价值联系起来。我们在这里研究表明真空能衰减为冷暗物质（CDM）的模型，并显示从宇宙微波背景（CMB）数据以及大型星系调查（例如Sloan Digital Sky Survey）获得的密度波动谱，对真空能量的衰减率设置了严格的限制。由衰减的真空能量产生的CDM将稀释在原始宇宙中产生的密度波动谱，并在低红移下通过大型星系调查观测到。我们的结果表明，真空能量进入CDM的衰减率非常小。
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