Dark energy problem: vacuum energy density discrepancy

Resolve the discrepancy between the quantum-field-theoretic prediction of vacuum energy density and the observed vacuum energy density inferred from the accelerated expansion of the universe, thereby addressing the dark energy problem.

Background

The authors note that dark energy is commonly associated with quantum vacuum energy, yet the value predicted by quantum field theory is vastly larger than the value inferred from cosmological observations. This longstanding mismatch is a central challenge in modern cosmology.

Within the paper's framework, dark energy is treated analogously to a superconducting medium, leading to a graviton mass and Yukawa-like modifications to gravity; nonetheless, the fundamental vacuum energy discrepancy is highlighted as unresolved.

References

However, this leads to the "dark energy problem" due to the discrepancy between the predicted and observed energy density of the vacuum. From the theoretical point of view, we can calculate the vacuum energy from the quantum fluctuations, however, the observed value of vacuum energy, inferred from the accelerated expansion of the universe, appears to be drastically smaller than the value predicted by theoretical calculations. This mismatch continues to be an open and unsolved problem in modern cosmology.

— Graviton mass due to dark energy as a superconducting medium: theoretical and phenomenological aspects (2404.03872 - Inan et al., 5 Apr 2024) in Section I. Introduction