Energy conditions in f( Q, Lm) gravity

Abstract

We are experiencing a golden age of experimental cosmology, with exact and accurate observations being used to constrain various gravitational theories like never before. Alongside these advancements, energy conditions play a crucial theoretical role in evaluating and refining new proposals in gravitational physics. We investigate the energy conditions (WEC, NEC, DEC, and SEC) for two f (Q, Lm) gravity models using the FLRW metric in a flat geometry. Model 1, f (Q, Lm) = −αQ + 2Lm + β, features linear parameter dependence, satisfying most energy conditions while selectively violating the SEC to explain cosmic acceleration. The EoS parameter transitions between quintessence, a cosmological constant, and phantom energy, depending on α and β. Model 2, f (Q, Lm) = −αQ +λ(2Lm)2 +β, introduces nonlinearities, ensuring stronger SEC violations and capturing complex dynamics like dark energy transitions. While Model 1 excels in simplicity, Model 2’s robustness makes it ideal for accelerated expansion scenarios, highlighting the potential of f (Q, Lm) gravity in explaining cosmic phenomena.