DESI: When the Dark Sector Speaks
Recent results from the Dark Energy Spectroscopic Instrument (DESI) have created excitement in the cosmology community by suggesting that dark energy may not be a constant after all. Instead, DESI’s measurements indicate that dark energy has evolved over time and even briefly behaved more repulsively than expected — a phenomenon known as “phantom crossing.”
Our recent work provides a natural and theoretically consistent explanation for this behaviour. We explored a scenario in which dark matter and dark energy interact with each other through a very gentle long-range force. This subtle interaction can make dark energy appear more repulsive in the past, exactly as DESI observes, without requiring any exotic or unstable physics. In our model, dark energy is described by an ordinary quintessence field with positive kinetic energy. However, because its energy is influenced by the behaviour of dark matter, the “effective” dark energy seen by observers naturally crosses the phantom line during cosmic evolution.
The model reproduces the pattern inferred by DESI: dark energy appears more strongly negative in the past and gradually approaches a milder value today. It also agrees well with combined data from DESI, Planck, and Type Ia supernova observations. This makes our approach one of the simplest and most robust explanations for DESI’s indication of evolving dark energy.
The results highlight the possibility that dark matter and dark energy — the two dominant but invisible components of the Universe — may not be independent, but instead quietly influence each other in a way that shapes cosmic history. Ongoing and future DESI data releases will allow us to test this idea further and explore whether interacting dark sectors hold the key to understanding the accelerated expansion of the Universe.
Journal Reference: Amlan Chakraborty, Prolay Chanda, Subinoy Das and Koushik Dutta; JCAP11(2025)047, https://arxiv.org/pdf/2503.10806
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Posted on: November 14th, 2025