Dark Energy with Phantom Crossing and the <i>H</i>₀ Tension

• Main Authors: Eleonora Di Valentino, Ankan Mukherjee, Anjan A. Sen
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Entropy
• Subjects: dark energy; cosmic microwave background; Hubble tension
• Online Access: https://www.mdpi.com/1099-4300/23/4/404

We investigate the possibility of phantom crossing in the dark energy sector and the solution for the Hubble tension between early and late universe observations. We use robust combinations of different cosmological observations, namely the Cosmic Microwave Background (CMB), local measurement of Hubble constant (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>H</mi><mn>0</mn></msub></semantics></math></inline-formula>), Baryon Acoustic Oscillation (BAO) and SnIa for this purpose. For a combination of CMB+BAO data that is related to early universe physics, phantom crossing in the dark energy sector was confirmed at a 95% confidence level and we obtained the constraint <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>H</mi><mn>0</mn></msub><mo>=</mo><mn>71</mn><mo>.</mo><msubsup><mn>0</mn><mrow><mo>−</mo><mn>3</mn><mo>.</mo><mn>8</mn></mrow><mrow><mo>+</mo><mn>2</mn><mo>.</mo><mn>9</mn></mrow></msubsup></mrow></semantics></math></inline-formula> km/s/Mpc at a 68% confidence level, which is in perfect agreement with the local measurement by Riess et al. We show that constraints from different combinations of data are consistent with each other and all of them are consistent with phantom crossing in the dark energy sector. For the combination of all data considered, we obtained the constraint <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>H</mi><mn>0</mn></msub><mo>=</mo><mn>70</mn><mo>.</mo><mn>25</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>78</mn></mrow></semantics></math></inline-formula> km/s/Mpc at a 68% confidence level and the phantom crossing happening at the scale factor <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>a</mi><mi>m</mi></msub><mo>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>851</mn><mrow><mo>−</mo><mn>0</mn><mo>.</mo><mn>031</mn></mrow><mrow><mo>+</mo><mn>0</mn><mo>.</mo><mn>048</mn></mrow></msubsup></mrow></semantics></math></inline-formula> at a 68% confidence level.