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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/212780
Running Vacuum and the ΛCDM tensions
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In the last few years a lot of work has provided significant support to the possibility that the vacuum energy density (VED), ρvac, is a running quantity throughout the cosmological history. Recent theoretical studies have shown that the properly renormalized ρvac in FLRW spacetime adopts the `running vacuum model' (RVM) form, in which the scaling with the renormalization point turns into dependence on the Hubble rate, H. The late time VED evolves as an additive term plus a dynamical component O(H2). Higher (even) powers O(H2n) are also predicted, which can trigger inflation in the early universe, although we shall not discuss this part here. In addition, the VED running is free from the quartic powers of the masses of the fields (∼m4) and hence the cosmic evolution of ρvac is really smooth. On the phenomenological side, the RVM fits the cosmological data remarkably well and it may help to reduce the H0 and σ8 tensions afflicting the ΛCDM. Overall, the RVM is sound since its theoretical structure can be derived from quantum field theory in curved spacetime and the model is phenomenologically consistent.
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SOLÀ PERACAULA, Joan. Running Vacuum and the ΛCDM tensions. Proceedings of Science. 2022. Vol. 106, num. 1-12. ISSN 1824-8039. [consulted: 11 of October of 2026]. Available at: https://hdl.handle.net/2445/212780