arXiv subjects

Shihabul Haque

Publications and source records attributed to Shihabul Haque.

3 recordsLinked to original sources

arXiv2025

Echoes in multi-ALP scenarios

We present a theoretical study of axion echoes in the context of multiple ALP models. We begin by reviewing the single ALP case, deriving the conditions for resonance and echo formation. Starting from a set of $N$ ALPs coupled to the photon, we then derive the relevant echo equations for both coherent and incoherent configurations. In the former case, we show that the echo power scales with $N$ leading to sharper amplification and potentially improving sensitivity estimates discussed earlier in literature. Small mass splittings between the ALPs further increase this amplification, even for a $N=2$ case. In the incoherent scenario, we show that the random phases lead to a suppression of the echo power, eventually resulting in observable signals akin to or even weaker than the single ALP case. We also outline the potential experimental implications of our results and discuss prospects for detecting these echoes in a wide range of ALP masses.

hep-ph↗

arXiv2024

Translating current ALP photon coupling strength bounds to the Randall-Sundrum model

In this article, we look at the current bounds on the coupling strength of axion-like particles (ALPs) with two photons in the context of the Randall-Sundrum (RS) model. We relate the coupling strength to the compactification radius that governs the size of the extra dimension in the RS warped geometry model and show how the current bounds on the ALP can be used to derive appropriate constraints on the size of the extra fifth dimension in the RS model. We show that the resulting constraints fail to resolve the gauge hierarchy problem for light/ultralight ALPs and require a massive ALP of at least $m_{a} \gtrsim 0.1$ [GeV] to be relevant in the context of the hierarchy problem when the gauge field is in the bulk.

hep-ph↗

arXiv2024

Interference aided finite resonant response in an undamped forced oscillator

We apply perturbative techniques to a driven undamped sinusoidal oscillator at resonance. The angular displacement, $θ$, obeys the dynamics $\Ddotθ + ω^{2} \sinθ = H\cos{ωt}$. The linearized approximation gives a divergent response (at long times) but the nonlinear terms make the response finite. We address the nonlinearity-induced finiteness in two ways by separately treating the short and long time scales. At long times, we use the traditional perturbative techniques to extract two drive dependent behaviours - one, the amplitude of oscillation scales as $(H/ω^{2})^{1/3}$ and, two, the time period of the slow mode varies as $(H/ω^{2})^{-2/3}$. For the early time behaviour, on the other hand, we devise an alternate perturbative expansion where the successive terms get larger with the order of evaluation but have alternating signs. The alternating signs (phase differences) between these terms leads to adestructive interference like effect. A careful consideration of this destructive interference like effect between successive terms leads to a finite response which describes the initial behaviour of the amplitude of the response reasonably correctly. We further note that for larger drive values, the system seems to undergo a first order transitional behaviour with a sudden jump in the largest Lyapunov exponent.

physics.class-ph↗