arXiv subjects

Hadyan L. Prihadi

Publications and source records attributed to Hadyan L. Prihadi.

4 recordsLinked to original sources

arXiv2026

Quantum speed limit for observables from quantum asymmetry

Quantum asymmetry and coherence are genuinely quantum resources that are essential to realize quantum advantage in information technologies. However, all quantum processes are fundamentally constrained by quantum speed limits, which raises the question on the corresponding bounds on the rate of consumption of asymmetry and coherence. In the present work, we derive a formulation of the quantum speed limit for observables in terms of the trace-norm asymmetry of the time-dependent quantum state relative to the observable. This quantum speed limit can be directly observed in experiment through weak value measurement and provides a lower bound to the quantum Fisher information about the parameter conjugate to the observable. It can be further related to quantum coherence relative to the eigenbasis of the observable. We obtain a complementary relation for the speed of three mutually unbiased observables for a single qubit. As an application, we derive a notion of a quantum thermodynamic speed limit.

quant-ph↗

arXiv2025

Rotating neutron stars with chaotic magnetic fields in general relativity and Rastall gravity

Observations indicate that the magnetic fields on neutron stars (NSs) lie in the range of $10^{8}$-$10^{15}$ G. We investigate rotating NSs with chaotic magnetic fields in both general relativity (GR) and Rastall gravity (RG). The equation of state (EOS) of NS matter is formulated within the framework of quantum hadrodynamics (QHD). The Hartle-Thorne formalism, extended to RG, is employed as an approximation for describing rotating NSs, while the magnetic field is modeled through an ansatz in which it is coupled to the energy density. We find that at high masses, neither rotation nor the Rastall parameter significantly affects the total mass, whereas the magnetic field strength can increase the maximum allowed mass. At lower masses, both the magnetic field and an increasing Rastall parameter reduce the stellar radius in the static configuration. Although higher angular velocities enhance stellar deformation, both magnetic field and larger Rastall parameter tend to suppress it. Regarding the moment of inertia, the Rastall parameter has little impact, whereas the magnetic field strength can increase it within the mass range $1.50$-$1.99 M_\odot$. All parameters considered in this study are consistent with observational constraints on the moment of inertia obtained from radio observations of massive pulsars.

astro-ph.HE↗

arXiv2025

Rotational mass of anisotropic neutron stars within Rastall gravity

Due to rotation, the mass correction of neutron stars arises and causes the rotational mass to be larger than the static mass. In this work, we extend the formulation of the rotational mass of anisotropic neutron stars within Rastall gravity. We apply numerical simulation on the formulation we obtained. We refer to mass of J0740+6620, GW170817, and GW190814 as the mass constraints of the neutron stars. For the free parameters, we use three values of Rastall's parameter, i.e. $λ=0.00019$, $λ=0.00038$, $λ=0.00071$; and three values of anisotropic strength, i.e. $ζ=-1.15$, $ζ=-1.50$, and $ζ=-2.00$. We have found that both $λ$ and $ζ$ impact on the increment of the NS's rotational mass within the compact regimes, and also impact on the decrease of the NS's rotational mass within the loose regimes. All mass constraints are satisfied by the NS with $ζ=-2.00$. In term of the moment of inertia $I$ of the neutron stars, all numerical results match with the constraint range which is based on radio observations of heavy pulsars; while in term of the angular velocity of the stars relative to the distant observers $Ω$, the mass correction $δM$ significantly increases when $Ω$ increases.

gr-qc↗

arXiv2019

Dynamics of Charged and Rotating NUT Black Holes in Rastall Gravity

In this work, we generalized the Kerr-Newman-NUT black hole solution in Rastall gravity from Ref. 1. Here we are more focused on the black hole dynamics such as the event horizons, ergosurface, ZAMO, thermodynamic properties, and the equatorial circular orbit around the black hole such as static radius limit, null equatorial circular orbit, and innermost stable circular orbit. We present how the NUT and Rastall parameter affects the dynamic of the black hole.

gr-qc↗