Quantum fine-tuning in stringy quintessence models
Quantum fine-tuning in stringy quintessence models
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DOI：
10.1016/j.physletb.2019.134878
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发表时间：
2018-12
影响因子：
4.4
通讯作者：
M. Hertzberg;M. Sandora;M. Trodden
中科院分区：
文献类型：
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作者：
M. Hertzberg;M. Sandora;M. Trodden
我们研究了在最近的沼泽地猜想的背景下对暗能量的精髓模型进行微调的程度。特别是，问题是是否存在双重微调，其中V和|∇V|是否被微调，或者是否由于自然产生的关系|∇V|∼V/M Pl而仅存在单个微调。我们发现，当进行经典处理时，这种关系确实在某些标量的简单弦紧化中自然出现，例如膨胀和体积模量。然而，我们发现量子效应会破坏这种自然关系，除非标量与物质扇区共形耦合。此外，众所周知，这种共形耦合通常可以通过第五力测试来排除。为了避免这第五种力量，一个有趣的建议是假设标量（精髓）仅与隐藏扇区耦合。然而，我们随后发现可见扇区标准模型粒子对 V 的量子修正通常会破坏这种关系。解决所有这些问题的一个可能的方法是将标量共形耦合到一个暗区，该暗区是标准模型的精确副本。这确保了即使当物质粒子在循环中运行时，关系|∇V|∼V/M Pl 也能自然地保持。然而，我们发现，如果有效理论的截止值大于 ∼ 0.1 GeV，则环路中五重子或引力子的量子修正会破坏这种关系。
We investigate the extent to which quintessence models for dark energy are fine-tuned in the context of recent swampland conjectures. In particular, the issue is whether there is a double fine-tuning in which both V and|∇ V| are fine-tuned, or whether there is only a single fine-tuning due to the relation|∇ V|∼ V/M Pl arising naturally. We find that indeed this relation arises naturally in simple string compactifications for some scalars, such as the dilaton and volume modulus, when treated classically. However, we find that quantum effects can spoil this natural relation, unless the scalar is conformally coupled to the matter sector. Furthermore, it is well known that such conformal couplings are generically ruled out by fifth force tests. To avoid these fifth forces, an interesting proposal is to assume the scalar (quintessence) only couples to the hidden sector. However, we then find quantum corrections to V from visible sector Standard Model particles generically spoil the relation. A possible way out of all these problems is to have the scalar conformally coupled to a dark sector that is an exact copy of the Standard Model. This ensures the relation|∇ V|∼ V/M Pl is maintained naturally even when matter particles run in the loop. However, we find that quantum corrections from quintessons or gravitons in the loop spoil the relation if the effective theory has a cutoff greater than∼ 0.1 GeV.