This paper proposes a self-consistent cosmic eternal cycle model based on general relativity and loop quantum gravity, which attempts to explain dark energy, cosmic expansion, and the heat death dilemma through a bidirectional black hole-white hole wall-breaking mechanism. The model suggests that the universe is not in a one-way expansion, but in a continuous cycle of contraction and expansion, thus avoiding the heat death end state.
Tianci Yang (Sun,) studied this question.