Estimating the quality factor Q accurately signifi cantly improves the seismic data resolution and reservoir characterization.The commonly used log-spectral ratio method uses least-squares fi tting to obtain Q values ...Estimating the quality factor Q accurately signifi cantly improves the seismic data resolution and reservoir characterization.The commonly used log-spectral ratio method uses least-squares fi tting to obtain Q values and involves only the amplitude information of seismic data while neglecting phase information.This paper proposes a joint interval Q inversion method based on the spectral ratio method and employs both amplitude and phase information to improve the accuracy.Based on the assumption that Q is independent of frequency,the nonlinear relation between the Q value and the two types of information is jointly used to construct an objective function,which clarifies the quantitative relation between amplitude spectrum,phase information,and Q value.The interval Q value can be inverted by calculating the minimum value of the objective function.The model test exhibits that the proposed method has higher precision and stability than the spectral ratio method;furthermore,the application to field data demonstrates that accurate Q inversion results are consistent with reservoir characteristics.展开更多
In a two-dimensional quantum dot （QD） with parabolic confinement potential, we investigate pure dephasing due to deformation potential exciton-bulk longitudinal acoustic phonons （LAP） interaction for exciton qubit...In a two-dimensional quantum dot （QD） with parabolic confinement potential, we investigate pure dephasing due to deformation potential exciton-bulk longitudinal acoustic phonons （LAP） interaction for exciton qubits under the influence of external static electric and magnetic fields by adopting the full quantum-mechanical method of Kunihiro Kojima and Akihisa Tomita. The wave function is found and the dependence of the pure dephasing factor on the confinement length of the QD and time and temperature is discussed. We find the external electric and magnetic fields have important effects on pure dephasing of exciton qubits because exciton-LAP interaction increases, leading to more pure dephasing.展开更多
In this letter, the superfluid-Mott-insulator phase transition of two-species cold bosonic atoms in an optical lattices is studied. The Hamiltonian of this model is diagonalized by means of Bogliubov transformations a...In this letter, the superfluid-Mott-insulator phase transition of two-species cold bosonic atoms in an optical lattices is studied. The Hamiltonian of this model is diagonalized by means of Bogliubov transformations and by the inversion symmetry of the optical lattice, the energy spectrum of this system is obtained. From She energy gap of the excitation spectrum, the quantum phase transition condition is obtained and it is determined by the competition between the interatomic repulsions and the tunnel coupling. It is found that there exists an ordinary fluid phase when taking the zero wave-vector limit.展开更多
Two linear In this letter, we prove the following conclusions by introducing a function Fn（t）： （1） If a quantum system S with a time-dependent non-degenerate Hamiltonian H（t） is initially in the n-th eigenstate...Two linear In this letter, we prove the following conclusions by introducing a function Fn（t）： （1） If a quantum system S with a time-dependent non-degenerate Hamiltonian H（t） is initially in the n-th eigenstate of H（0）, then the state of the system at time t will remain in the n-th eigenstate of H（t） up to a multiplicative phase factor if and only if the values Fn（t） for all t are always on the circle centered at 1 with radius 1; （2） If a quantum system S with a time-dependent Hamiltonian H（t） is initially in the n-th eigenstate of H（0）, then the state of the system at time t will remain c-uniformly approximately in the n-th eigenstate of H（t） up to a multiplicative phase factor if and only if the values F,（t） for all t are always outside of the circle centered at 1 with radius 1-ε. Moreover, some quantitative sufficient conditions for the state of the system at time t to remain ε-uniformly approximately in the n-th eigenstate of H（t） up to a multiplicative phase factor are established. Lastly, our results are illustrated by a spin-half particle in a rotating magnetic field.展开更多
This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes.It is based on an analysis of the data from four observational wells at ...This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes.It is based on an analysis of the data from four observational wells at boundaries between distinct active blocks of China mainland.These wells are also situated on several active fault zones and have exhibited considerable responses to the Wenchuan Ms8.0 earthquake of 2008 in China.We collected hourly records of water levels of these wells from 2007to 2009 and processed these data for analysis.The tidal factors,phase lags,and phase-difference changes of tidal residuals of each well were calculated.We found that when the Wenchuan quake happened,the tidal factors of the 4 wells were changing rapidly,while their phase lags and phase differences of tidal residuals declined swiftly,which may reflect the stress and strain changes of the well-aquifer system during the seismic generation.展开更多
In this paper, we present a quantitative sufficient condition for adiabatic approximation in PT-symmetric quantum mechanics,which yields that a state of the PT-symmetric quantum system at any time will remain approxim...In this paper, we present a quantitative sufficient condition for adiabatic approximation in PT-symmetric quantum mechanics,which yields that a state of the PT-symmetric quantum system at any time will remain approximately in the m-th eigenstate up to a multiplicative phase factor whenever it is initially in the m-th eigenstate of the Hamiltonian. In addition, we estimate the approximation errors by the distance and the fidelity between the exact solution and the adiabatic approximate solution to the time evolution equation, respectively.展开更多
The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resol...The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.展开更多
基金supported by the National Natural Science Foundation of China(41774137)the National Grand Project for Science and Technology(2017ZX05032003)the Fundamental Research Funds for the Central Universities(19CX02002A)
文摘Estimating the quality factor Q accurately signifi cantly improves the seismic data resolution and reservoir characterization.The commonly used log-spectral ratio method uses least-squares fi tting to obtain Q values and involves only the amplitude information of seismic data while neglecting phase information.This paper proposes a joint interval Q inversion method based on the spectral ratio method and employs both amplitude and phase information to improve the accuracy.Based on the assumption that Q is independent of frequency,the nonlinear relation between the Q value and the two types of information is jointly used to construct an objective function,which clarifies the quantitative relation between amplitude spectrum,phase information,and Q value.The interval Q value can be inverted by calculating the minimum value of the objective function.The model test exhibits that the proposed method has higher precision and stability than the spectral ratio method;furthermore,the application to field data demonstrates that accurate Q inversion results are consistent with reservoir characteristics.
基金supported by National Natural Science Foundation of China under Grant No.10347004
文摘In a two-dimensional quantum dot （QD） with parabolic confinement potential, we investigate pure dephasing due to deformation potential exciton-bulk longitudinal acoustic phonons （LAP） interaction for exciton qubits under the influence of external static electric and magnetic fields by adopting the full quantum-mechanical method of Kunihiro Kojima and Akihisa Tomita. The wave function is found and the dependence of the pure dephasing factor on the confinement length of the QD and time and temperature is discussed. We find the external electric and magnetic fields have important effects on pure dephasing of exciton qubits because exciton-LAP interaction increases, leading to more pure dephasing.
基金＊The project partly supported by National Natural Science Foundation of China under Grant No. 10574060 and the Natural Science Foundation of Shandong Province of China under Grant No. Y2003A02
文摘In this letter, the superfluid-Mott-insulator phase transition of two-species cold bosonic atoms in an optical lattices is studied. The Hamiltonian of this model is diagonalized by means of Bogliubov transformations and by the inversion symmetry of the optical lattice, the energy spectrum of this system is obtained. From She energy gap of the excitation spectrum, the quantum phase transition condition is obtained and it is determined by the competition between the interatomic repulsions and the tunnel coupling. It is found that there exists an ordinary fluid phase when taking the zero wave-vector limit.
基金supported by the National Natural Science Foundation of China(Grant No. 11171197)the IFGP of Shaanxi Normal University(Grant No. 2011CXB004)the FRF for the Central Universities(Grant No. GK201002006)
文摘Two linear In this letter, we prove the following conclusions by introducing a function Fn（t）： （1） If a quantum system S with a time-dependent non-degenerate Hamiltonian H（t） is initially in the n-th eigenstate of H（0）, then the state of the system at time t will remain in the n-th eigenstate of H（t） up to a multiplicative phase factor if and only if the values Fn（t） for all t are always on the circle centered at 1 with radius 1; （2） If a quantum system S with a time-dependent Hamiltonian H（t） is initially in the n-th eigenstate of H（0）, then the state of the system at time t will remain c-uniformly approximately in the n-th eigenstate of H（t） up to a multiplicative phase factor if and only if the values F,（t） for all t are always outside of the circle centered at 1 with radius 1-ε. Moreover, some quantitative sufficient conditions for the state of the system at time t to remain ε-uniformly approximately in the n-th eigenstate of H（t） up to a multiplicative phase factor are established. Lastly, our results are illustrated by a spin-half particle in a rotating magnetic field.
基金supported by National Natural Science Foundation of China(Grant No.40930637)Special Project for Earthquake Science(Grant No.200808079)Subject Foundation of Ministry of Education for Doctor Candidates in Universities(Grant No.20100022110001)
文摘This work focuses on variations of the Earth tidal factor and phase lag derived from groundwater observations before and after major earthquakes.It is based on an analysis of the data from four observational wells at boundaries between distinct active blocks of China mainland.These wells are also situated on several active fault zones and have exhibited considerable responses to the Wenchuan Ms8.0 earthquake of 2008 in China.We collected hourly records of water levels of these wells from 2007to 2009 and processed these data for analysis.The tidal factors,phase lags,and phase-difference changes of tidal residuals of each well were calculated.We found that when the Wenchuan quake happened,the tidal factors of the 4 wells were changing rapidly,while their phase lags and phase differences of tidal residuals declined swiftly,which may reflect the stress and strain changes of the well-aquifer system during the seismic generation.
基金supported by the National Natural Science Foundation of China(Grant Nos.11171197 and 11371012)the Science Research Foundation of Education Department of Shaanxi Provincial Government(Grant No.11JK0513)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.GK201402005 and GK201301007)the Postdoctoral Science Foundation of China(Grant No.2014M552405)the Natural Science Research Program of Shaanxi Province(Grant No.2014JQ1010)
文摘In this paper, we present a quantitative sufficient condition for adiabatic approximation in PT-symmetric quantum mechanics,which yields that a state of the PT-symmetric quantum system at any time will remain approximately in the m-th eigenstate up to a multiplicative phase factor whenever it is initially in the m-th eigenstate of the Hamiltonian. In addition, we estimate the approximation errors by the distance and the fidelity between the exact solution and the adiabatic approximate solution to the time evolution equation, respectively.
基金supported by the Joint Fund for Fostering Talents of National Natural Science Foundation of China and Henan Province(Grant No.U1304618)the Open Fund of Key Laboratory of Precision Navigation and Timing Technology of Chinese Academy of Sciences(Grant No.2012PNTT01)+4 种基金the Postdoctoral Grant of China(Grant Nos.2011M501446,2012T50798)the Basic and Advanced Technology Research Foundation of Henan Province(Grant No.122300410169)The Key Science and Technology Foundation of Zhengzhou City(Grant Nos.131PPTGG411-6,131PCXTD594)the Doctor Fund of Zhengzhou University of Light Industry(Grant No.2011BSJJ031)the Fundamental Research Funds for the Central Universities(Grant No.K5051204003)
文摘The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.
