Multimessenger Astronomy Beyond the Standard Model: New Window from Quantum Sensors

Abstract

Ultralight bosonic (ULB) fields with mass $m_φ \ll 1$~eV often arise in theories beyond the Standard Model (SM). If such fields exist, violent astrophysical events that result in emission of gravitational wave, photon, or neutrino signals could also produce bursts of high-density relativistic ULB fields. Detection of such ULB fields in terrestrial or space-based laboratories correlated with other signals from transient astrophysical events opens a novel avenue for multimessenger astronomy. We show that quantum sensors are particularly well-suited to observe emitted scalar and pseudoscalar axion-like ULB fields coupled to SM. We demonstrate that multimessenger astronomy with ULB fields is possible even when accounting for matter screening effects.

Figures (28)

• Figure 1: Illustration of multimessenger astronomy potential through synergy of astrophysical electromagnetic (photon, $\gamma$), gravitational wave (GW) and neutrino ($\nu$) messengers together with ULB fields. Here, dots represent potential other astrophysical messengers, such as charged particles. Possible sources of standard astrophysical signals accompanied by relativistic bursts of ULB fields include transient astrophysical systems such as compact object (black hole, neutron star) mergers or supernovae as well as those originating from new physics beyond SM, such as boson star bosenovae. Two characteristic scenarios of messenger propagation towards detecting experiments are depicted: when sources are extragalactic (top) and fields could traverse ISM of multiple galaxies, as well as when source emission is within the Milky Way Galaxy (bottom) and fields propagate through the Galaxy's ISM whose gas number density varying with galacto-centric distance $R$. Detection of ULB fields is illustrated involving terrestrial Earth-based or space-based quantum sensor experiments such as those based on precision clocks or laser/atom interferometers. ULB field signals from new physics (periwinkle shading), as well as astrophysical messenger signals (green shading) are shown. Milky Way image adopted from NASA Hurt_2017.
• Figure 2: Induced effective quadratic ULB field coupling to photons arising from loop-level contributions of linear ULB coupling to electrons.
• Figure 3: Schematic representation of medium (e.g. Earth, galactic matter) screening ULB wave, analogous to a finite-width potential barrier in quantum mechanics. Due to the quadratic $\phi-$SM coupling, a dense matter medium like Earth behaves as a potential barrier with a height $V_{\rm barrier} = \sum_i 8\pi\,d_i^{(2)} \rho_i/(m_{\phi}M_{\text{pl}}^2)$. If the wave energy $\omega$ is less than $V_{\rm barrier}$, $\phi$ primarily reflects off the barrier, with an exponentially suppressed amplitude inside. The indices of refraction, $n_1(\omega)$ outside and $n_2(\omega)$ inside the barrier, depend on $\phi$'s energy. For $\omega > V_{\rm barrier}$, the wave transmits through the barrier with reduced kinetic energy due to the increased effective mass, resulting in slower propagation.
• Figure 4: Group velocity of $\phi$ waves as a function of the ratio $(m_{\phi}^2 +\beta)/\omega^2$ at $V(\phi = \langle \phi \rangle)$, for different choices of potential $p$ values for $\phi^p$ (see App. \ref{['app:potential']}). Reference bare $\phi$ field mass scenario without matter density contributions and $\beta = 0$ (red dashed line) delineates screening and anti-screening regimes. Schematic potential structure with respect to respective regions in the top figure is displayed on the bottom.
• Figure 5: Duration of the signal at the detector, $\tilde{t}_*$, as a function of the time delay, $\delta t$. Different benchmarks for energy and intrinsic burst duration are shown, distinguished by colors and linestyles, respectively. The gray shaded region is excluded by the uncertainty principle relating the intrinsic burst duration and the energy of the emitted ULBs. All curves assume the minimal uncertainty case, $\delta \omega = 1/(2 t_*)$. For larger $\delta \omega$, the nonzero-slope portions of the curves would shift upward linearly.