Gravitational waves from extreme mass ratio inspirals around a hairy Kerr black hole

Recently, Contreras et al. \cite{Contreras:2021yxe} introduced a new type of black hole, called hairy Kerr black hole (HKBH), which describes a Kerr BH surrounded by an axially symmetric fluid with conserved energy momentum tensor. In this paper, we compute the gravitational waves emitted from the extreme mass ratio inspirals around the HKBHs. We solve the Dudley-Finley equation, which describes the gravitational perturbations of the HKBH, and obtain the energy fluxes induced by a stellar-mass compact object moving on the equatorial, circular orbits. Using the adiabatic approximation, we evolved the radii of the circular orbits by taking into account the backreaction of gravitational radiation. Then we calculate the dephasing and mismatch of the EMRI waveforms from the HKBH and Kerr BH to assess the difference between them. The results demonstrate that the EMRI waveforms from the HKBH with deviation parameter larger than $0.001$ and hair charge smaller than $1.5M$ can be discerned by LISA.Comment: 8 pages, 4 figures, v2: minor changes, accepted by PR

Probing the Tidal Deformability of the Central Object in an Extreme Mass Ratio Inspiral with Analytic Kludge Waveforms

We have developed approximate "analytic kludge" waveforms to describe the inspiral of a stellar-mass compact object into a supermassive compact object (SMCO) in an extreme mass ratio inspiral (EMRI) scenario. The deformability of the SMCO is characterized by a dimensionless quantity called the tidal Love number (TLN). Our analysis shows that, up to the leading order of the mass ratio, the conservative dynamics of the EMRI are not affected by tidal interaction, and the tidal effect is only present in the induced quadrupole moment. We have calculated the energy and angular momentum fluxes and obtained leading order corrections to the orbital evolution equations. By comparing the waveforms with and without tidal interaction, we demonstrate that even a small TLN can produce significant differences in the waveforms, which can be detected by space-borne detector LISA. Finally, using the Fisher information matrix method, we have performed parameter estimation for the TLN and found that the precision can reach the level of $10^{-4}$ in suitable scenarios.Comment: 12 pages, 4 figure

Gravitational waves from extreme-mass-ratio inspirals in the semiclassical gravity spacetime

More recently, Fernandes \cite{Fernandes:2023vux} discovered analytic stationary and axially-symmetric black hole solutions within semiclassical gravity, driven by the trace anomaly. The study unveils some distinctive features of these solutions. In this paper, we compute the gravitational waves emitted from the \ac{EMRI} around these quantum-corrected rotating black holes using the kludge approximate method. Firstly, we derive the orbital energy, angular momentum and fundamental frequencies for orbits on the equatorial plane. We find that, for the gravitational radiation described by quadrupole formulas, the contribution from the trace anomaly only appears at higher-order terms in the energy flux when compared with the standard Kerr case. Therefore, we can compute the EMRI waveforms from the quantum-corrected rotating black hole using the Kerr fluxes. We assess the differences between the EMRI waveforms from rotating black holes with and without the trace anomaly by calculating the dephasing and mismatch. Our results demonstrate that space-borne gravitational wave detectors can distinguish the EMRI waveform from the quantum-corrected black holes with a fractional coupling constant of $\sim 10^{-3}$ within one year observation. Finally, we compute the constraint on the coupling constant using the Fisher information matrix method and find that the potential constraint on the coupling constant by LISA can be within the error $\sim 10^{-4}$ in suitable scenarios.Comment: 11 pages,7 figures,1 tabl

Research on forming quality of poly-wedge pulley spinning

As an important power transmission part, pulleys are widely used in automobile industry, agricultural machinery, pumps and machines. A near-net forming process for six-wedge belt pulleys manufacturing was put forward. For this purpose, the required tooth shape and size can be formed directly by spinning without machining. The whole manufacturing procedures include blanking, drawing and spinning. The spinning procedure includes five processes, performing, drumming, thickening, toothing and finishing. The forming defects occurred during each forming processes of poly-wedge pulley spinning, such as the drumming failure, flanged opening-end, folded side-wall, insufficient bottom size, flashed opening-end, cutting-off bottom, are introduced, and the factors influencing the defects are analyzed. The corresponding preventive measures are put forward

Lasing oscillation condition and group delay control in gain-assisted plasmon-induced transparency

A gain-assisted plasmonic waveguide with two detuned resonators is investigated in the plasmon-induced transparency window. Phase map is employed to study power transmittance and group delay for varying gain coefficients and frequency detunings of the two resonators. The gain coefficient for lasing oscillation condition is analytically shown to vary quadratically with the frequency detuning. In the amplification regime below the lasing threshold, the spectrum implies not only large group delay, but also high transmittance and narrow linewidth. This is in contrast to those in the loss-compensation regime and the passive case in which there always exists a trade-off between the linewidth and the peak transmittance.Comment: 15 pages, 4 figure

Controlling Entanglement Dynamics by Choosing Appropriate Ratio between Cavity-Fiber Coupling and Atom-Cavity Coupling

The entanglement characteristics including the so-called sudden death effect between two identical two-level atoms trapped in two separate cavities connected by an optical fiber are studied. The results show that the time evolution of entanglement is sensitive not only to the degree of entanglement of the initial state but also to the ratio between cavity-fiber coupling () and atom-cavity coupling (). This means that the entanglement dynamics can be controlled by choosing specific v and g.Comment: 14pages, 3figures, conferenc

2,2-Dimethyl-5-{[(4-nitro­phen­yl)amino]­methyl­idene}-1,3-dioxane-4,6-dione

In the title compound, C13H12N2O6, the dihedral angle between the benzene ring and the amino­methyl­ene unit is 5.42 (16)°, while the angle between the amino­methyl­ene unit and the dioxane ring is 3.06 (43)°. The dioxane ring shows a half-boat conformation, in which the C atom between the dioxane ring O atoms is 0.464 (10) Å out of the plane. An intra­molecular N—H⋯O hydrogen bond stabilizes the mol­ecular conformation. In the crystal, a three-dimensional framework is built up via inter­molecular N—H⋯O hydrogen bonds