Direct Detection of Dark Energy

Aug 10, 2021, 9:30 AM


Surjeet Rajendran (Johns Hopkins University)


If dark energy evolves in time, its dynamical component could be tested in the laboratory. There are two kinds of tests. First, the coherent motion of the dark energy can lead to precession of spins of particles that are coupled to the dark energy. This leads to a dc precession of particle spins and it can be probed in storage ring experiments as well as experiments that search for Lorentz violation. Second, the dark energy can convert into a bath of dark radiation. Within current constraints this radiation could have up to ~ 10^3 timesmore energy density than the cosmic microwave background. In particular models, a rolling scalar field can generate different forms of dark radiation
such as hidden photons, milli-charged particles and even Standard Model neutrinos. The leading effect on the late-time cosmological expansion history depends on a single parameter beyond Lambda CDM - namely the temperature of the dark radiation today. Cosmological observations of this modified expansion rate could provide a striking signature of this scenario. The dark radiation itself could even be directly detectable in laboratory experiments, suggesting a broader experimental program into the nature of dark energy.

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