Axion Receiver: Binary Stars Guarding Dark Matter ✦
Original: "Reflection polarization of close binaries as a probe of axion dark matter birefringence"
Close binary systems act as natural polarimetric clocks, allowing us to catch the ultra-faint jitter of the polarization plane caused by axion dark matter.
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Binary stars pulse with polarized light, like the most precise orbital clocks. Axion dark matter weaves barely audible notes into this rhythm—side frequencies in the harmonic spectrum. If we catch this trembling, we’ll hear the music of the invisible Universe. Perhaps this is how we’ll first sense the breath of the hidden sector.
🎯 In Spica, the polarization of reflected light is only 200 millionths. This used to be beyond imagination, but polarimeters like HIPPI-2 make such measurements routine. And it is in this microscopic jitter that dark matter’s signature might be hiding.
z_{\rm obs}(t) - z_s(t) \simeq 2i\theta_a(t)z_0 + \theta_{a,0}\sum_{n} [c_{n,+}e^{i(n\Omega+\mu)t} + c_{n,-}e^{i(n\Omega-\mu)t} + ...]
The signal appears as sidebands around the orbital harmonics, like modulation of a radio wave.
\sigma(g_{a\gamma}) \sim 2.4\times10^{-12}\,{\rm GeV}^{-1} \left(\frac{\mu}{10^{-20}\,{\rm eV}}\right) \left(\frac{300\,{\rm ppm}}{P_{\rm rms}}\right) \left(\frac{\sigma_p}{10\,{\rm ppm}}\right) \sqrt{\frac{t_{\rm cad}}{10\,{\rm min}}\frac{30\,{\rm day}}{T_{\rm obs}}}
Sensitivity for a single binary with μ¹ Sco parameters; shows how to improve the result with increasing precision and observation time.
Scientists
Alan GuthAndrei LindeGeorges LemaîtreJames PeeblesAdam RiessBrian Schmidtaxion
dark matter
polarimetry
cosmic microwave background
pulsar
protoplanetary disk
stellar evolution
numerical simulation
Machine LearningLaws
Friedmann equationsHubble's lawgravitational lensingPlanck's lawvirial theoremChandrasekhar limit