»ã±¨±êÌâ (Title)£ºProbing the dynamics of dark energy from latest cosmological observations£¨´Óµ±Ç°ÓîÖæѧ¹Û²â̽Ë÷¶¯Á¦Ñ§°µÄÜÁ¿£©

»ã±¨ÈË (Speaker)£º ²ÌÒ»·ò ½ÌÊÚ£¨Öйú¿Æѧ¼¼Êõ´óѧ£©

»ã±¨¹¦·ò (Time)£º2025Äê2ÔÂ21ÈÕ(ÖÜÎå) 10:00-11:30

»ã±¨µØÖ· (Place)£ºÐ£±¾²¿ D117

Ô¼ÇëÈË (Inviter)£º¸ðÏÈ»Ô

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ÌáÒª (Abstract)£º

Astonishingly, human beings discovered that distant Type Ia supernovae (SN Ia) were accelerating away at an increasing pace. This led to the great discovery of late-time cosmic acceleration and brought us the concept of dark energy, responsible for such a phenomenon, but the underlying nature remains mysterious. Theoretically, modified gravity can be a framework to provide an alternative explanation for the the existence of dark energy. In this talk, we will go further into the effective field theory of f(T) gravity and beyond. Then using the latest Dark Energy Spectroscopic Instrument (DESI) data combined with other observations, we reconstructed the cosmological background evolution and find that the reconstructed dark-energy equation-of-state (EoS) parameter w(z) exhibits the so-called quintom-B behavior, crossing ?1 from phantom to quintessence regime as the universe expands. In particular, we reconstruct the corresponding actions for f(R), f(T), and f(Q) gravity, respectively. We conclude that, certain modified gravity such as metric-affine gravity can exhibit the quintom dynamics and fit the recent DESI data efficiently, and for all cases the quadratic deviation from the ¦«CDM scenario is mildly favored.