arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1810.09474astro-ph.COhep-th
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统一超流暗区

Unified Superfluid Dark Sector

Elisa G. M. Ferreira, Guilherme Franzmann, Justin Khoury, Robert Brandenberger

摘要:

我们提出了一个新的理论,一个统一的黑暗部门,晚时间宇宙加速出现的暗物质超流框架。该系统被描述为一个超流混合物组成的两个可区分的状态与一个小的能隙,如基态和激发态的暗物质。鉴于它们在超流体中的接触,这些状态之间的相互作用可能发生,将一个状态转换为另一个状态。超流体内部的这种长程相互作用通过由约瑟夫森/拉比相互作用激发的余弦势将两种超流体声子物质耦合。由于这种潜在的,一个新的动力学的后期加速膨胀出现在这个系统中,而不需要暗能量,来自宇宙只包含这个两个状态DM超流体。由于超流体是非相对论性的,它们的声速在整个演化过程中保持适当的小。我们计算了线性微扰的膨胀历史和增长,并将结果与$Λ$ CDM宇宙学进行了比较。对于所研究的基准参数,预测的膨胀和增长函数与$Λ$ CDM接近,但预测的增长率在后期差异显著。目前的理论很好地补充了最近提出的暗物质超流性来解释修正牛顿动力学(MOND)在星系尺度上的经验成功,从而提供了一个统一的框架暗物质,暗能量,和MOND现象。

英文摘要:

We present a novel theory of a unified dark sector, where late-time cosmic acceleration emerges from the dark matter superfluid framework. The system is described by a superfluid mixture consisting of two distinguishable states with a small energy gap, such as the ground state and an excited state of dark matter. Given their contact in the superfluid, interaction between those states can happen, converting one state into the other. This long range interaction within the superfluid couples the two superfluid phonon species through a cosine potential motivated by Josephson/Rabi interactions. As a consequence of this potential, a new dynamics of late-time accelerated expansion emerges in this system, without the need of dark energy, coming from a universe containing only this two-state DM superfluid. Because the superfluid species are non-relativistic, their sound speeds remain suitably small throughout the evolution. We calculate the expansion history and growth of linear perturbations, and compare the results to $Λ$CDM cosmology. For the fiducial parameters studied here, the predicted expansion and growth function are close to those of $Λ$CDM, but the difference in the predicted growth rate is significant at late times. The present theory nicely complements the recent proposal of dark matter superfluidity to explain the empirical success of MOdified Newtonian Dynamics (MOND) on galactic scales, thus offering a unified framework for dark matter, dark energy, and MOND phenomenology.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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