arXiv subjects

M. Afif Ismail

Publications and source records attributed to M. Afif Ismail.

5 recordsLinked to original sources

arXiv2026

Cryogenic sub-Hz cROss torsion bar detector with quantum NOn-demolition Speed meter (CHRONOS) for gravitational wave detection

We present the optical design and sensitivity modeling of the Cryogenic sub-Hz cROss torsion-bar detector with quantum NOn-demolition Speed meter (CHRONOS), a triangular Sagnac speed-meter interferometer incorporating power and signal recycling. Using ABCD-matrix analysis and \textsc{Finesse3} simulations, we obtain stable optical eigenmodes with mode-matching efficiencies above 99.5%. The optimized configuration achieves a quantum-noise-limited strain sensitivity of $h \simeq 3\times10^{-18},\mathrm{Hz^{-1/2}}$ at 1 Hz, with a ring-cavity finesse of $\mathcal{F}\simeq3.1\times10^{4}$ and a round-trip Gouy phase of $ψ\approx153^{\circ}$. The low-frequency quantum noise is primarily governed by the power-recycling cavity detuning, while the signal-recycling cavity produces an approximately uniform quadrature rotation. An optimal homodyne angle of $ζ\simeq46^{\circ}$ provides the best sensitivity near 1 Hz. Assuming an end-mirror reflectivity of $R_{\mathrm{ETM}}=99.9999%$ at 10 K, CHRONOS can achieve quantum-noise-limited performance on a laboratory scale. Its projected science reach includes intermediate-mass black-hole binaries out to approximately $271,\mathrm{Mpc}$, a 10-year stochastic-background sensitivity of $Ω_{\mathrm{GW}}\simeq4.7\times10^{-4}$ at $2.15,\mathrm{Hz}$, constraints on Yukawa-type deviations from Newtonian gravity, and prompt gravity-gradient signals from nearby earthquakes.

physics.ins-det↗

arXiv2026

CHRONOS: Cryogenic sub-Hz cROss torsion bar detector with quantum NOn-demolition Speed meter

We propose a next-generation ground-based gravitational-wave detector, Cryogenic sub-Hz cROss torsion-bar detector with quantum NOn-demolition Speed meter (CHRONOS), optimized for the unexplored $0.1$-$10\,\mathrm{Hz}$ band between the space-based LISA and future ground-based detectors such as Cosmic Explorer and the Einstein Telescope. CHRONOS combines a ring-cavity Sagnac interferometer with torsion-bar test masses to realize the first quantum nondemolition (QND) measurement of angular momentum in a macroscopic system. By implementing a speed-meter readout in the rotational degree of freedom, CHRONOS coherently cancels quantum radiation-pressure noise and enables sub-Hz observations. We calculate, for the first time, that detuned power-recycling and cavity-length optimization can simultaneously relax technical requirements on both torsion bars and speed meters. Assuming a realistic optical design with 1m torsion bar, we estimate strain sensitivities of $h \simeq 5\times10^{-19}\,\mathrm{Hz^{-1/2}}$ at $2\,\mathrm{Hz}$ for detectors with arm lengths of $2.5$ m, $40$ m, and $300$ m. These sensitivities enable (i) direct detection of intermediate-mass black hole binaries up to 340\,Mpc with SNR=3, (ii) probing SGWB down to $Ω_{\mathrm{GW}}\sim\ 3\times10^{-4}$ at 0.2 Hz with 5 year accumulation. Furthermore, CHRONOS enable to prompt detection of gravity-gradient signals from M 5.5 earthquakes even with a $2.5$ m prototype. CHRONOS thus opens new opportunities for quantum-limited geophysical observation and multi-band, multi-messenger gravitational-wave astronomy.

astro-ph.IM↗

arXiv2024

Dark Photon-Photon Resonance Conversion of GRB221009A through Extra Dimension

The recently observed very high energy (VHE) photons dubbed as GRB221009A by several terrestrial observatories such as LHAASO and Carpet-2 require a physics explanation beyond the standard model. Such energetic gamma ray bursts, originating from yet unknown very distance source at redshift z = 0.1505, would be directly scattererd by extragalactic background lights (EBL) rendering its improbable detection at the earth. We show that dark photon which resides in extra dimension would be able to resolve this issue when it oscillates resonantly with the photon in similar fashion with neutrino oscillation. We demonstrate that, for dark photon mass equals to 1 eV, the probability of GRB221009A photons with energy above 0.2 TeV to reach the earth lies in the range between $10^{-6} \, \text{to} \, 95\% $ for kinetic mixing values $10^{-14} \leq ε\leq 10^{-12.5}$ allowed by current constraints.

hep-ph↗

arXiv2023

Exploring dark photons via a subfrequency laser searchin gravitational wave detectors

We propose a novel idea to detect a dark photon in gravitational wave experiments. Our setups are capable of performing the whole process of dark photon production, its decay products, and new physics signal discovery. This mini-LHC is inspired by the recent idea of dark photon detection using laser light in light shining through the wall (LSW) experiments such as ALPS II. Taking the subfrequency light emitted from the laser source as the new physics signal, we show that the sensitivity of our proposal is 2orders of magnitude better than the original idea in the LSW studies.

hep-ph↗

arXiv2021

Late time tails and nonlinear memories in asymptotically de Sitter spacetimes

We study the propagation of a massless scalar wave in de Sitter spacetime perturbed by an arbitrary central mass. By focusing on the late time limit, this probes the portion of the scalar signal traveling inside the null cone. Unlike in asymptotically flat spacetimes, the amplitude of the scalar field detected by an observer at timelike infinity does not decay back to zero but develops a spacetime constant shift - both at zeroth and first order in the central mass M. This indicates that massless scalar field propagation in asymptotically de Sitter spacetimes exhibits both linear and nonlinear tail-induced memories. On the other hand, for sufficiently late retarded times, the monopole portion of the scalar signal measured at null infinity is found to be amplified relative to its timelike infinity counterpart, by its nonlinear interactions with the gravitation field at first order in M.

gr-qc↗