基于DESI DR2 BAO与DESI DR1全形状测量重新审视亚稳态暗能量
Revisiting Metastable Dark Energy in Light of DESI DR2 BAO and DESI DR1 Full-Shape Measurements
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中文总结 AI 辅助
本研究结合DESI DR2 BAO、DESI DR1全形状测量等多组宇宙学数据，约束三类亚稳态暗能量模型，发现部分数据组合存在与ΛCDM模型的轻微偏差，但尚无决定性证据支持非零暗能量衰变率，为后续利用更全数据深化研究提供依据。
中文摘要 AI 辅助
我们重新审视由类放射性衰变定律描述的亚稳态暗能量（DE）模型。我们考虑三种情形：一种有效的、指数衰减的暗能量组分；暗能量衰变为非重子暗物质（DM）；以及暗能量衰变为暗辐射（DR）。我们利用DESI DR2重子声学振荡（BAO）数据、Ia型超新星（SNIa）、宇宙微波背景（CMB）观测结果，并且首次结合当前可用的DESI DR1全形状（FS）成团测量数据，对亚稳态暗能量模型进行约束。BAO+SNIa的组合数据显示出对正的$Γ/H_0$的轻微偏好，与$Λ$CDM极限的偏差达到$\boldsymbol{\not\boldsymbol{\raise{2mu}{\boldsymbol{>}}}}} 2σ$水平。这对应着暗能量密度的衰减，以及低红移下类似精质的有效行为。然而，一旦纳入来自Planck或P-ACT的宇宙微波背景信息，约束结果便在统计上与$Γ/H_0=0$保持一致。全形状测量探测了增长领域，并有助于区分模型2的相互作用型暗物质-暗能量行为、模型1的有效衰变暗能量响应，以及模型3中更弱的暗辐射诱导响应。对于CMB+FS+DES-Dovekie的组合数据，模型1显示出与$Γ/H_0=0$的轻微偏差，达到$\boldsymbol{\not\boldsymbol{\raise{2mu}{\boldsymbol{>}}}}} 2σ$水平，而模型2和3在$2σ$范围内仍与$Λ$CDM极限一致。总体而言，亚稳态暗能量在唯象上仍然成立：当前数据允许晚期动力学的存在，但并未为非零衰变率提供决定性证据。这些结果推动我们将分析扩展到即将发布的DESI DR2全形状数据，以获得对亚稳态动力学更严格的约束。
英文摘要
We revisit metastable dark energy (DE) models described by a radioactive-like decay law. We consider three scenarios: an effective, exponentially decaying DE component; decay of DE into non-baryonic dark matter (DM); and decay of DE into dark radiation (DR). We constrain the metastable DE models using DESI DR2 baryon acoustic oscillation (BAO) data, Type Ia supernovae (SNIa), cosmic microwave background (CMB) observations, and, for the first time, the current available DESI DR1 full-shape (FS) clustering measurements. The BAO+SNIa combinations show a mild preference for positive $Γ/H_0$, with a deviation from the $Λ$CDM limit at the $\gtrsim 2σ$ level. This corresponds to a decaying DE density and an effective quintessence-like behaviour at low redshift. Once CMB information from either Planck or P-ACT is included, however, the constraints become statistically consistent with $Γ/H_0=0$. The FS measurements probe the growth sector and help distinguish the interacting DM-DE behaviour of Model 2 from the effective decaying-DE response of Model 1 and the weaker DR-induced response of Model 3. For CMB+FS+DES-Dovekie, Model 1 shows a slight deviation from $Γ/H_0=0$ at the $\gtrsim 2σ$ level, while Models 2 and 3 remain consistent with the $Λ$CDM limit within $2σ$. Overall, metastable DE remains phenomenologically viable: current data allow late-time dynamics but do not provide decisive evidence for a nonzero decay rate. These results motivate extending our analysis to the upcoming DESI DR2 FS data to obtain tighter constraints on metastable dynamics.
