1,482 research outputs found
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 and hair charge smaller than 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 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 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
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
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