By using the partial wave method, we investigate the absorption of a massless scalar wave from a Schwarzschild black hole surrounded by quintessence. We obtained the expression of absorption cross sectionσabs（ω）=...By using the partial wave method, we investigate the absorption of a massless scalar wave from a Schwarzschild black hole surrounded by quintessence. We obtained the expression of absorption cross sectionσabs（ω）=π/ω^2 ∑ t=0^∞ （2l＋1）｜Tωl（ω）｜^2=π/ω^2∑ t=0^∞（2l＋1）Гωl（ω）.Then we numerically carry out the absorption cross section and we find that the larger the angular momentum quantum number 1 is, the smaller the corresponding maximum value of the partial absorption cross section is, and that the total absorption cross section tends to the geometric-optical limit σhfabs≈ bc^2. We also find that higher value of ωq （state abs parameter of quintessence） corresponds to the higher value of absorption cross section gabs.展开更多
We analyze the Sehrodinger-type scalar wave equation of an extended black hole in f（R） gravity, and numerically investigate its absorption/scattering cross sections using the partial wave method. It is found that th...We analyze the Sehrodinger-type scalar wave equation of an extended black hole in f（R） gravity, and numerically investigate its absorption/scattering cross sections using the partial wave method. It is found that the dimension of length a makes the peak value of the effective scattering potential fall down, and the absorption cross section oscillates around the geometric optical value in the high frequency regime. We can also see that the scattering flux becomes stronger and its angle width becomes narrower in the forward direction, the glory peak becomes lower and the glory width becomes narrower along the backward direction when the coupling parameter α increases.展开更多
Matching boundary conditions(MBC’s)are proposed to treat scalar waves in the body-centered-cubic lattices.By matching the dispersion relation,we construct MBC’s for normal incidence and incidence with an angle a.Mul...Matching boundary conditions(MBC’s)are proposed to treat scalar waves in the body-centered-cubic lattices.By matching the dispersion relation,we construct MBC’s for normal incidence and incidence with an angle a.Multiplication of MBC operators then leads to multi-directional absorbing boundary conditions.The effectiveness are illustrated by the reflection coefficient analysis and wave packet tests.In particular,the designed M1M1 treats the scalar waves in a satisfactory manner.展开更多
In this paper we have discussed geodesics and the motion of test particle in the gravitational field of noncommutative charged black hole spacetime. The motion of massive and massless particle have been discussed sepe...In this paper we have discussed geodesics and the motion of test particle in the gravitational field of noncommutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately.A comparative study of noncommutative charged black hole and usual Reissner–Nordstr¨om black hole has been done.The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.展开更多
In this paper, the Riemann solutions for scalar conservation laws with discontinuous flux function were constructed. The interactions of elementary waves of the conservation laws were concerned, and the numerical simu...In this paper, the Riemann solutions for scalar conservation laws with discontinuous flux function were constructed. The interactions of elementary waves of the conservation laws were concerned, and the numerical simulations were given.展开更多
This paper research on the pointwise behavior of perturbations from a viscous shock solution to a scalar viscous conservation law by introducing an approximate Green’s function. The authors obtain not only the pointw...This paper research on the pointwise behavior of perturbations from a viscous shock solution to a scalar viscous conservation law by introducing an approximate Green’s function. The authors obtain not only the pointwise decay of the perturbation and but also the high derivative of it. Stability in anyL(p≥1) norm is a direct consequence.展开更多
From the equations of motion for baryons in the scalar strong interaction hadron theory (SSI), two coupled third order radial wave equations for baryon doublets have been derived and published in 1994. These equations...From the equations of motion for baryons in the scalar strong interaction hadron theory (SSI), two coupled third order radial wave equations for baryon doublets have been derived and published in 1994. These equations are solved numerically here, using quark masses obtained from meson spectra and the masses of the neutron, ?0 and ?0 as input. Confined wave functions dependent upon the quark-diquark distance as well as the values of the four integration constants entering the quark-diquark interaction potential are found approximately. These approximative, zeroth order results are employed in a first order perturbational treatment of the equations of motion for baryons in SSI for free neutron decay. The predicted magnitude of neutron’s half life agrees with data. If the only free parameter is adjusted to produce the known A asymmetry coefficient, the predicted B asymmetry agrees well with data and vice versa. It is pointed out that angular momentum is not conserved in free neutron decay and that the weak coupling constant is detached from the much stronger fine structure constant of electromagnetic coupling.展开更多
The nonlinear interactions between zonal flow and Rossby waves are studied by numerical simulations with focus on the effects of scalar nonlinearity. The numerical results show that the scalar nonlinearity has an appr...The nonlinear interactions between zonal flow and Rossby waves are studied by numerical simulations with focus on the effects of scalar nonlinearity. The numerical results show that the scalar nonlinearity has an appreciable influence on the Rossby dipole evolution and can reduce the threshold of the disturbance energy increase.展开更多
We revisit the vital issue of gauge dependence in the scalar-induced secondary gravitational waves(SIGWs), focusing on the radiation domination(RD) and matter domination(MD) eras. The energy density spectrum is the ma...We revisit the vital issue of gauge dependence in the scalar-induced secondary gravitational waves(SIGWs), focusing on the radiation domination(RD) and matter domination(MD) eras. The energy density spectrum is the main physical observable in such induced gravitational waves. For various gauge choices, there has been a divergence in the energy density, ?GW, of SIGWs.We calculate SIGWs in diferent gauges to quantify this divergence to address the gauge-dependent problem. In our previous studies, we had found that the energy density diverges in the polynomial power of conformal time(e.g., η^(6) in uniform density gauge). We try to fix this discrepancy by adding a counter-term that removes the fictitious terms in secondary tensor perturbations. We graphically compare the calculations in various gauges and also comment on the physical origin of the observed gauge dependence.展开更多
The process of primordial black hole(PBH)formation is inevitably accompanied by scalar induced gravitational waves(SIGWs).The strong correlation between PBH and SIGW signals may offer a promising approach to detecting...The process of primordial black hole(PBH)formation is inevitably accompanied by scalar induced gravitational waves(SIGWs).The strong correlation between PBH and SIGW signals may offer a promising approach to detecting PBHs in upcoming gravitational wave experiments,such as the Laser Interferometer Space Antenna(LISA).We investigate third order SIGWs during a radiation-dominated era in the case of the monochromatic primordial power spectrum Pζ=Aζkσ(k-k*).For LISA observations,the relationships between the signal-to-noise ratio(SNR)and monochromatic primordial power spectrum are studied systematically,revealing that the effects of third order SIGWs extend the cutoff frequency from 2f+to 3f and lead to an approximately 200%increase in the SNR for the frequency band from 10^(-5)Hz to 1.6×10^(-3)Hz,corresponding to PBHs with masses in the range 4×10^(-12)M⊙~10^(-7)M⊙.We find that there is a critical value,A×=1.76×10^(-2),for the amplitude of the monochromatic primordial power spectra,such that when Aζ>A*,the energy density of third order SIGWs is larger than that of second order SIGWs.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 10873004)the State Key Development Program for Basic Research of China (Grant No. 2010CB832803)the Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0964)
文摘By using the partial wave method, we investigate the absorption of a massless scalar wave from a Schwarzschild black hole surrounded by quintessence. We obtained the expression of absorption cross sectionσabs（ω）=π/ω^2 ∑ t=0^∞ （2l＋1）｜Tωl（ω）｜^2=π/ω^2∑ t=0^∞（2l＋1）Гωl（ω）.Then we numerically carry out the absorption cross section and we find that the larger the angular momentum quantum number 1 is, the smaller the corresponding maximum value of the partial absorption cross section is, and that the total absorption cross section tends to the geometric-optical limit σhfabs≈ bc^2. We also find that higher value of ωq （state abs parameter of quintessence） corresponds to the higher value of absorption cross section gabs.
基金Supported by the National Natural Science Foundation of China under Grant No 10873004the National Basic Research Program of China under Grant No 2010CB832803the Program for Changjiang Scholars and Innovative Research Team in University under Grant No IRT0964
文摘We analyze the Sehrodinger-type scalar wave equation of an extended black hole in f（R） gravity, and numerically investigate its absorption/scattering cross sections using the partial wave method. It is found that the dimension of length a makes the peak value of the effective scattering potential fall down, and the absorption cross section oscillates around the geometric optical value in the high frequency regime. We can also see that the scattering flux becomes stronger and its angle width becomes narrower in the forward direction, the glory peak becomes lower and the glory width becomes narrower along the backward direction when the coupling parameter α increases.
基金This research is partially supported by NSFC under grant number 91016027National Basic Research Program of China under contract numbers 2010CB731500.
文摘Matching boundary conditions(MBC’s)are proposed to treat scalar waves in the body-centered-cubic lattices.By matching the dispersion relation,we construct MBC’s for normal incidence and incidence with an angle a.Multiplication of MBC operators then leads to multi-directional absorbing boundary conditions.The effectiveness are illustrated by the reflection coefficient analysis and wave packet tests.In particular,the designed M1M1 treats the scalar waves in a satisfactory manner.
文摘In this paper we have discussed geodesics and the motion of test particle in the gravitational field of noncommutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately.A comparative study of noncommutative charged black hole and usual Reissner–Nordstr¨om black hole has been done.The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.
基金Project supported by National Natural Science Foundation of China(Grant No .10271072)
文摘In this paper, the Riemann solutions for scalar conservation laws with discontinuous flux function were constructed. The interactions of elementary waves of the conservation laws were concerned, and the numerical simulations were given.
基金the National Natural Science Foundation of China(10131050)
文摘This paper research on the pointwise behavior of perturbations from a viscous shock solution to a scalar viscous conservation law by introducing an approximate Green’s function. The authors obtain not only the pointwise decay of the perturbation and but also the high derivative of it. Stability in anyL(p≥1) norm is a direct consequence.
文摘From the equations of motion for baryons in the scalar strong interaction hadron theory (SSI), two coupled third order radial wave equations for baryon doublets have been derived and published in 1994. These equations are solved numerically here, using quark masses obtained from meson spectra and the masses of the neutron, ?0 and ?0 as input. Confined wave functions dependent upon the quark-diquark distance as well as the values of the four integration constants entering the quark-diquark interaction potential are found approximately. These approximative, zeroth order results are employed in a first order perturbational treatment of the equations of motion for baryons in SSI for free neutron decay. The predicted magnitude of neutron’s half life agrees with data. If the only free parameter is adjusted to produce the known A asymmetry coefficient, the predicted B asymmetry agrees well with data and vice versa. It is pointed out that angular momentum is not conserved in free neutron decay and that the weak coupling constant is detached from the much stronger fine structure constant of electromagnetic coupling.
基金supported by the National Natural Science Foundation of China(Grant No.41175052)
文摘The nonlinear interactions between zonal flow and Rossby waves are studied by numerical simulations with focus on the effects of scalar nonlinearity. The numerical results show that the scalar nonlinearity has an appreciable influence on the Rossby dipole evolution and can reduce the threshold of the disturbance energy increase.
基金National Natural Science Foundation of China under Grant Nos.10475055 and 90503006the Scientific Research Fund of the Education Department of Zhejiang Province under Grant No.20040969
基金supported by the National Natural Science Foundation of China (Grant Nos. 12175105, 12147175, 12247170, 11575083, and 11565017)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP)。
文摘We revisit the vital issue of gauge dependence in the scalar-induced secondary gravitational waves(SIGWs), focusing on the radiation domination(RD) and matter domination(MD) eras. The energy density spectrum is the main physical observable in such induced gravitational waves. For various gauge choices, there has been a divergence in the energy density, ?GW, of SIGWs.We calculate SIGWs in diferent gauges to quantify this divergence to address the gauge-dependent problem. In our previous studies, we had found that the energy density diverges in the polynomial power of conformal time(e.g., η^(6) in uniform density gauge). We try to fix this discrepancy by adding a counter-term that removes the fictitious terms in secondary tensor perturbations. We graphically compare the calculations in various gauges and also comment on the physical origin of the observed gauge dependence.
基金Supported by the National Nature Science Foundation of China(12075249,11690022)the Key Research Program of the Chinese Academy of Sciences(XDPB15)。
文摘The process of primordial black hole(PBH)formation is inevitably accompanied by scalar induced gravitational waves(SIGWs).The strong correlation between PBH and SIGW signals may offer a promising approach to detecting PBHs in upcoming gravitational wave experiments,such as the Laser Interferometer Space Antenna(LISA).We investigate third order SIGWs during a radiation-dominated era in the case of the monochromatic primordial power spectrum Pζ=Aζkσ(k-k*).For LISA observations,the relationships between the signal-to-noise ratio(SNR)and monochromatic primordial power spectrum are studied systematically,revealing that the effects of third order SIGWs extend the cutoff frequency from 2f+to 3f and lead to an approximately 200%increase in the SNR for the frequency band from 10^(-5)Hz to 1.6×10^(-3)Hz,corresponding to PBHs with masses in the range 4×10^(-12)M⊙~10^(-7)M⊙.We find that there is a critical value,A×=1.76×10^(-2),for the amplitude of the monochromatic primordial power spectra,such that when Aζ>A*,the energy density of third order SIGWs is larger than that of second order SIGWs.
