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Guihua Tian

Publications and source records attributed to Guihua Tian.

At least 19 recordsLinked to original sources
arXiv2015

Study of the Spin-weighted Spheroidal Wave Equation in the Case of s=3/2

In this paper, we use the means of super-symmetric quantum mechanics to study of the Spin-weighted Spheroidal Wave in the case of s=3/2. We obtain some interesting results: the first-five terms of the super-potential, the general form of the super-potential. The ground eigen-function and eigenvalue of the equation are also given. According these results, we make use of the shape invariance property to compute the exited eigenvalues and eigen-functions. These results help us to understand the Spin-weighted Spheroidal Wave and show that it is integral.

quant-ph↗
arXiv2015

The new explanation of cluster synchronization in the generalized Kuramoto system

The cluster synchronization is a very important characteristic for the higher harmonic coupling Kuramoto system. A novel transformation is provided, and it gives cluster synchronization by the periodic properties of the density function. The periodic properties of the density function also make the cluster sections' boundaries barrier-like, which helps to explain the sensitiveness of cluster synchronization on the initial conditions of the oscillators. Detailed numerical studies confirm the theoretical predictions from this new view of the symmetry transformation. The work is very beneficial to the further study on cluster synchronization in various systems.

nlin.CD↗
arXiv2015

Research on the recurrence relations for the spin-weighted spheroidal harmonics

In this paper we study the recurrence relations in the spin-weighted spheroidal harmonics (SWSHs) through super-symmetric quantum mechanics. We use the shape invariance property to solve the spin-weighted spheroidal wave equations. The result shows the relation among SWSHs with a special condition of the same parameter magnetic quantum number m but different spin-weight s. The conclusions can be reduced to the famous recurrence relations of spin-weighted spherical harmonics. These contents are the first investigation of this kind recurrence relation concerning SWSHs and make it possible to derive SWSHs from the spheroidal harmonics, so they are very important both in theoretical background and in the astrophysical applications. Keywords: spin-weighted spheroidal harmonics, recurrence relation, super-symmetric quantum mechanics, shape-invariance

gr-qc↗
arXiv2015

The symmetry of the Kuramoto system and the essence of the cluster synchronization

The cluster synchronization (CS) is a very important characteristic for the higher harmonic cou- pling Kuramoto system. A novel method from the symmetry transformation is provided, and it gives CS a profoundly mathematical explanation and clear physical annotation. Detailed numerical studies for the order parameters in various conditions confirm the theoretical predictions from this new view of the symmetry transformation. The work is very beneficial to the further study on CS in various systems.

nlin.CD↗
arXiv2013

The entanglement of two qubits coupled ultrastrongly with a quantum oscillator

We explore the possibility of the controlled manipulation of the entanglement of two qubits with an external apparatus, the Rabi Hamiltonian. The novel results show that the initially entangled two qubits could have very high probability to stay unchanged by the coherent state of the photon with chosen parameters. If the inter-qubit coupling strength is negative, their entanglement could be kept for a much longer time by a relatively strong external quantum control with the suitable and novel choice of some parameters. Furthermore, their entanglement will not show any sudden death and revival. All these results are different from the previous studies and they are given with reasonable explanations. The maintaining of the entanglement of the two qubits with very high fidelity will be very helpful for the quantum information process.

quant-ph↗
arXiv2013

Use strong coupling strength to coherently preserve quantum entanglement

The dynamics of two qubits ultra-strongly coupled with a quantum oscillator is investigated by the adiabatic approximation method. The evolution formula of the initial four Bell states are studied under the control mechanism of the coherent state of the quantum oscillator. The influential parameters for the preservation of the entanglement are the four parameters: the average number of the coherent state, the ultra-strong coupling strength, the ratio of two frequencies of qubit and oscillator, and the inter-interaction coupling of the two qubits. The novel results show that the appropriate choice of these parameters can enable this mechanism to be utilized to preserve the entanglement of the two qubits, which is initially in the state |I_0> of the four Bell states. We give two different schemes to choose the respective parameters to maintain the entangled state |I_0> almost unchanged. The results will be helpful for the quantum information process.

quant-ph↗
arXiv2012

A New Integral Equation for the Spheroidal equations in case of m equal 1

The spheroidal wave functions are investigated in the case m=1. The integral equation is obtained for them. For the two kinds of eigenvalues in the differential and corresponding integral equations, the relation between them are given explicitly. Though there are already some integral equations for the spheroidal equations, the relation between their two kinds of eigenvalues is not known till now. This is the great advantage of our integral equation, which will provide useful information through the study of the integral equation. Also an example is given for the special case, which shows another way to study the eigenvalue problem.

physics.gen-ph↗
arXiv2011

Polarization of light and the spin state of photon

The comparison of the polarization and spin of light is presented in the paper. It is shown that it is more easier and clearer to use the polarization of the light to explain the effect of the interaction of light and atoms than that of spin of the light. The paper also gives rise to the question whether or not the concept of spin for photon have any essence for its existence.

physics.gen-ph↗
arXiv2010

The integral property of the spheroidal wave functions

The perturbation method in supersymmetric quantum mechanics (SUSYQM) is used to study whether the spheroidal equations have the shape-invariance property. Expanding the super-potential term by term in the parameter alpha and solving it, we find that the superpotential loses its shape-invariance property upon to the second term. This first means that we could not solve the spheroidal problems by the SUSQM; further it is not unreasonable to say they are non-solvable in some sense.

quant-ph↗
arXiv2010

Study of the Spin-weighted Spheroidal Equation in the Case of s=1

We present series study of using the method of super-symmetric quantum mechanics(SUSYQM) solving the spin-weighted spheroidal wave equation. In this paper, we obtain the first four terms of super-potential of the spin-weighted spheroidal wave equation in the case of s=1. These results may help summary the general form for the n-th term of the super-potential, which is proved correct by means of induction. We finally compute the ground eigenvalues and ground eigenfunction. All the results may be of significative for studies of electromagnetic radiation processes near rotating black holes and compute radiation reaction in curved space-time.

math-ph↗
arXiv2010

The Spin-weighted Spheroidal Wave functions in the Case of s=1/2

The spin-weighted spheroidal equations in the case s=1/2 is thoroughly studied in the paper by means of the perturbation method in supersymmetry quantum mechanics. The first-five terms of the super-potential in the series of the parameter beta are given. The general form of the nth term of the superpotential is also obtained, which could derived from the previous terms W_{k}, k<n. From the results, it is easy to give the ground eigenfunction of the equation. Furthermore, the shape-invariance property is investigated in the series form of the parameter beta and is proven kept in this series form for the equations. This nice property guarantee one could obtain the excited eigenfunctions in the series form from the ground eigenfunctions by the method in supersymmetry quantum mechanics. This shows the perturbation method method in supersymmetry quantum mechanics could solve the spin-weight spheroidal wave equations completely in the series form of the small parameter beta.

math-ph↗
arXiv2010

New Investigation on the Spheroidal Wave Equations

Changing the spheroidal wave equations into new Schro$dinger's form, the super-potential expanded in the series form of the parameter $α$are obtained in the paper. This general form of the super-potential makes it easy to get the ground eigenfunctions of the spheroidal equations. But the shape-invariance property is not retained and the corresponding recurrence relations of the form (4) could not be extended from the associated Legendre functions to the case of the spheroidal functions.

physics.gen-ph↗
arXiv2010

A new model for the double well potential

A new model for the double well potential is presented in the paper. In the new potential, the exchanging rate could be easily calculated by the perturbation method in supersymmetric quantum mechanics. It gives good results whether the barrier is high or sallow. The new model have many merits and may be used in the double well problem.

quant-ph↗
arXiv2009

Some properties of accelerating observers in the Schwarzschild space

It is well known that observers will be accelerated when they approach the planets. Thus, discussing the properties of accelerating observers in the Schwarzschild space is of sense. For the sake of simplicity, we can construct these observers' world lines by comparing with the observers in the Hawking effect and Unruh effect, whose world lines are both hyperbolic curves in the appropriate coordinates. We do it after defining a certain special null hypersurface in the Kruskal coordinates. Our result shows that these accelerating observers defined in our paper can also detect the radiation with the analogy of the Unruh effect, though locally. Furthermore, we conjecture that, for any null hypersurface in any spacetime, the corresponding observers who can at least locally detect the radiation from it can be found.

gr-qc↗
arXiv2005

The stable problem of the black-hole connected region in the Schwarzschild black hole

The stability of the Schwarzschild black hole is studied. Using the Painlevé coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequency whose imaginary must not be greater than -1/4m, so the black-hole-connected regionis stable in physicist' viewpoint; (2) On the contrary, in the mathematicians' viewpoint, the existence of the real frequencies means that the stable problem is unsolved by the linear perturbation method in the black-hole-connected region.

gr-qc↗
arXiv2005

Does the Schwarzschild black hole really exist?

We use the Kruskal time coordinate T to define the initial time. By this way, it naturally divides the stable study into one connected with the two regions: the white-hole-connected region and the black-hole-connected region. The union of the two regions covers the Schwarzschild space-time (r>2m). We also obtain the very reasonable conclusion: the white-hole-connected region is instable; whereas the black-hole-connected region is stable. If we take the instability with caution and seriousness, it might be not unreasonable to regard that the Schwarzschild black hole might be instable too.

gr-qc↗
arXiv2005

Reconsideration of the Regge-Wheeler equation

Reconsideration of the Regge-Wheeler equation is processed by using the Painlevé coordinate and "good" timelier to define the initial time. We find that: the Regge-Wheeler equation could has positive imaginary frequency. Because the Regge-Wheeler equation is the odd (angular) perturbation to the Schwarzschild black hole, the conclusion is that the Schwarzschild black hole is unstable with respect to the rotating perturbation.

gr-qc↗