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The application of eigenvalue theory to dual quaternion Hermitian matrices holds significance in the realm of multi-agent formation control. In this paper, we study the Rayleigh quotient iteration (RQI) for solving the right eigenpairs of dual quaternion Hermitian matrices. Combined with dual representation, the RQI algorithm can effectively compute the eigenvalue along with the associated eigenvector of the dual quaternion Hermitian matrices. Furthermore, by utilizing minimal residual property of the Rayleigh Quotient, a convergence analysis of the Rayleigh quotient iteration is derived. Numerical examples are provided to illustrate the high accuracy and low CPU time cost of the proposed Rayleigh quotient iteration compared with the power method for solving the dual quaternion Hermitian eigenvalue problem., Comment: arXiv admin note: text overlap with arXiv:2111.12211 by other authors

Reducing noises and enhancing signal-to-noise ratios (SNRs) have become critical for designing third-generation gravitational-wave (GW) detectors with a GW strain of less than $10^{-23}$/$\rm \sqrt{Hz}$. In this paper, we propose a potential third-generation GW detector based on autocorrelative weak-value amplification (AWVA) for GW detection with a strain of $h_g =$ $4 \times 10^{-25}$/$\rm \sqrt{Hz}$. In our scheme, a GW event induces a phase difference $\Delta \phi$ by passing through an 11-bounce delay line, 10-km arm-length, zero-area Sagnac interferometer illuminated with a 1064-nm laser. Subsequently, $\Delta \phi$ is amplified as the parameter of post-selection by choosing the appropriate pre-selected state and coupling strength in AWVA. In particular, we theoretically investigate the AWVA measurements for GW detection within the frequency band of 200 Hz $\leq$ $f_g$ $\leq$ 800 Hz, considering Gaussian noises with negative-decibel SNRs. The peak response of the AWVA sensitivity $\kappa(f_g)$ occurs at frequency $f_{g, max}$ = 500 Hz, which falls within the frequency band of interest of the current third-generation GW detectors. Our simulation results indicate that AWVA can demonstrate a measurable sensitivity of $\Theta(f_g)$ within the frequency band of interest. Moreover, the robustness of WVA shows promising potential in mitigating the effects of Gaussian noises., Comment: 21 pages, 6 figures

Accurate knowledge of the spectral features of noise and their influence on open quantum systems is fundamental for quantitative understanding and prediction of the dynamics in a realistic environment. For the weak measurements of two-level systems, the weak value obtained from experiments will inevitably be affected by the noise of the environment. Following our earlier work on the technique of the auto-correlative weak-value amplification (AWVA) approach under a Gaussian noise environment, here we study the effect of non-Gaussian noise on the AWVA technique.In particular, two types of noise with a negative-dB signal-to-noise ratio, frequency-stationary noises and frequency-nonstationary noises are studied. The various frequency-stationary noises, including low-frequency (1/f) noises, medium-frequency noises, and high-frequency noises, are generated in Simulink by translating the Gaussian white noise with different band-pass filters. While impulsive noise is studied as an example of frequency-non stationary noises. Our simulated results demonstrate that 1/f noises and impulsive noises have greater disturbance on the AWVA measurements. In addition, adding one kind of frequency-stationary noise, clamping the detected signals, and dominating the measurement range may {have} the potential to improve the precision of the AWVA technique with both a smaller deviation of the mean value and a smaller error bar in the presence of many hostile non-Gaussian noises., Comment: 22 pages,8 figures

We study the influence of light quark loops on the Wigner phase by solving coupled Dyson-Schwinger equations for quark propagator and gluon propagator. We take the gluon propagator in the Nambu phase from $N_f$ = 2 unquenched lattice QCD and choose various phenomenological models for the quark-gluon vertex. The gluon propagator in Winger phase is assumed to be different from that in the Nambu phase only due to the vacuum polarization of the quark loop. We obtain the Wigner solution of the coupled equations, compared with that from solving only the equation of the quark propagator. We discussed the corrections by the light quark loops and the dependence on various models of the quark-gluon vertex., Comment: 12 pages, 8 figures

Recently, weak value $\rm A_w$ derived in the pre- and post-selected weak measurement has been shown to be powerful in measuring minute physical effects. In principle, the decrease in the post-selection probability will increase the sensitivity. Besides, the sensitivity which characterizes the pointer position shift is proportional to the real part of $\rm A_w$, and the sensitivity which characterizes the pointer shift in momentum space is proportional to the imaginary part of $\rm A_w$. However, we find that the relationship between the post-selection probability and the sensitivity is true when $\rm A_w$ is a purely real number or a purely imaginary number. The plural $\rm A_w$ will lead to the abnormal behavior where the decrease in the post-selection probability reduce the sensitivity at certain pre- and post-selection. In addition, considering the device imperfections and the environmental instability in the WVA protocol, this anomaly raised from plural $\rm A_w$ will reduce the sensitivity and generate a systematic error of the measurement compared with the original scheme. Finally, three feasible methods are proposed to reduce these negative effects when the weak measurement inevitably changes into measurement with a plural weak value., Comment: 10 pages, 10 figures

Recently, biased weak measurement(BWM) has shown higher precision than both conventional measurement and standard weak measurement(SWM) in optical metrology. In this paper, we propose a scheme of detecting rotation velocity in Sagnac's interferometer with BWM. In particular, BWM employs an additional reduction of photons in the post-selection by introducing a pre-coupling, and the remaining photons have been shown to be extremely sensitive to the estimated parameter. In addition, our numerical results show that the scheme with BWM can obtain a higher sensitivity than the scheme with SWM., Comment: 6 pages, 6 figures

Weak measurement has enabled fundamental studies in both experiment and theory of quantum measurement. Numerous researches have indicated that weak measurements have a wide range of application and scientific research value. In our work, we used bibliometric methods to evaluate the global scientific output of research on Weak measurement and explore the current status and trends in this field from 2000 to 2020. The R bibliometric package was used for quantitative and qualitative analyses of publication outputs and author contributions. In total, 636 related articles and reviews were included in the final analysis. The main results were as follows: The number of publications has increased substantially with time. Physical Review A was the most active journal. The country and institution contributing the most to this field were The United States and University Rochester respectively. The analysis of the conceptual structure of keywords indicated that weak measurements were involved a variety of metrology, quantum communication, and nonclassical features of quantum mechanics. Our bibliometric analysis shows that weak measurement research continues to be a hot-spot. The focus has evolved to study quantum information and amplify weak signals., Comment: 16 pages, 9 figures

A modified-weak-value-amplification(MWVA) technique of measuring the mirror's velocity based on the Vernier-effect has been proposed. We have demonstrated with sensitivity-enhanced and the higher signal-to-noise ratio(${\rm SNR}$) by using two cascaded Michelson interferometers. These two interferometers are composed of similar optical structures. One interferometer with a fixed mirror acts as a fixed part of the Vernier-scale, while the other with a moving mirror acts as a sliding part of the Vernier-scale for velocity sensing. The envelope of the cascaded interferometers shifts much more than a single one with a certain enhancement factor, which is related to the free space range difference between these two interferometers. In addition, we calculate the ${\rm SNR}$ based on the Fisher information with both the MWVA technique and the traditional-weak-value-amplification(TMVA) technique. The results show that the ${\rm SNR}$ with our MWVA technique is larger than the the ${\rm SNR}$ with the TWVA technique within the range of our time measurement window. Our numerical analysis proved that our MWVA technique is more efficient than the TWVA technique. And by using the principles of the Vernier-effect, it is applicative and convenient to ulteriorly improving the sensitivity and ${\rm SNR}$ in measuring other quantities with the MWVA technique., Comment: 8 figures, 10 page

The operator-product expansion(OPE) could be employed to obtain the lowest-order, nonlocal quark scalar condensate component of gluon vacuum polarization. In particular, nonlocal quark scalar condensate can be calculated by solving Dyson-Schwinger Equation(DSE) of QCD. Then, field-theoretic aspects of the gluon vacuum polarization and nonperturbative gluon propagator will be considered in the Landau gauge of the Lorentz gauge fixing. The gluon propagator we obtained is finite in the infrared domain where the single gluon mass $m_g$ can be determined. Our results of the ratio $m_{g}/\Lambda_{QCD}$ the range of that from 1.33 to 1.39 agree with previous determinations for this ratio. Besides, the analytic structure of the gluon propagators from the OPE's result is explored. Our numerical analysis of the gluon' Schwinger function finds clear evidence of the positivity violations in the gluon propagator. In addition, a new method for obtaining the chemical potential dependence of the gluon vacuum polarization and the dressed gluon propagator is developed., Comment: 9 pages, 14 figures

We put forward a new fiber optic sensor for measuring linear velocity with picometer/second sensitivity with Weak-value amplification based on generalized Sagnac effect [Phys. Rev. Lett.\textbf{93}, 143901(2004)].The generalized Sagnac effect was first introduced by Yao et al, which included the Sagnac effect of rotation as a special case and suggested a new fiber optic sensor for measuring linear motion with nanoscale sensitivity. By using a different scheme to perform the Sagnac interferometer with the probe in momentum space, we have demonstrated the new weak measure protocol to detect the linear velocity by amplifying the phase shift of the generalized Sagnac effect. Given the maximum incident intensity of the initial spectrum, the detection limit of the intensity of the spectrometer, we can theoretically give the appropriate pre-selection, post-selection, and other optical structures before the experiment. Our numerical results show our scheme with Weak-value amplification is effective and feasible to detect linear velocity with picometer/second sensitivity which is three orders of magnitude smaller than the result $\nu$=4.8 $\times$ $10^{-9}$ m/s obtained by generalized Sagnac effect with same fiber length., Comment: 3 figures; 9 pages. arXiv admin note: substantial text overlap with arXiv:2105.13638

We study the amplification of weak magnetic field with Weak-value technique based on Faraday magneto-optic effect. By using a different scheme to perform the Sagnac interferometer with the probe in momentum space, we have demonstrated the new weak measure protocol to detect the small weak magnetic field by amplifying the phase shift of Faraday magneto-optic effect. At the given the maximum incident intensity of the initial spectrum, the detection limit of the intensity of the spectrometer and the accuracy of detecting weak magnetic field, we can theoretically give the appropriate pre-selection, post-selection and others optical structure before experiment. Our numerical results show our scheme with Weak-value technique is effective and feasible to detect weak magnetic field with magnetic field intensity lower than $10^{-10}$ T., Comment: 3 figures. arXiv admin note: text overlap with arXiv:2101.00857

We study the amplification of rotation velocity with the Sagnac interferometer based on the concept of weak-value amplification. By using a different scheme to perform the Sagnac interferometer with the probe in momentum space, we have demonstrated the new weak measure protocol to detect the small rotation velocity by amplifying the phase shift of the Sagnac effect. At the given the maximum incident intensity of the initial spectrum, the detection limit of the intensity of the spectrometer and the accuracy of angular velocity measurement, we can theoretical give the appropriate potselection and the minimum of optical path area before experiment. In addition, we put forward a new optical design to increase the optical path area and decrease the size of the interferometer to overcome the limit of instrument size. Finally, our modified Sagnac's interferometer based on weak measurement is innovative and efficient probing the small rotation velocity signal., Comment: arXiv admin note: text overlap with arXiv:1203.0827 by other authors

In this paper, we present two feasible and efficient methods to numerically solve the quark's Dyson-Schwinger (qDSE), the qDSE is mathematical systems of nonlinear integral equations of the second kind with high degrees of freedom. It is difficult to analytically solve the qDSE due to its non-linearity and the singularity. Normally we discrete the singular integral equation by Gauss Legendre integral integration formula, then the approximate solutions of integral equation are obtained by iterative method. The main difficulty in the progress is the unknown function, which is the quark's propagator at vacuum and at finite chemical potential, occurs inside and outside the integral sign. Because of the singularity, the unknown function inside the integral sign need to be interpolate with high precision. Normally traditional numerical examples show the interpolation will cost a lot of CPU time. In this case, we provide two effective and efficient methods to optimize the numerical calculation, one is we put forward a modified interpolation method to replace the traditional method. Besides, the technique of OpenMP and automatic parallelization in GCC is another method which has widely used in modern scientific computation. Finally, we compare CPU time with different algorithm and our numerical results show the efficiency of the proposed methods., Comment: 10 pages, 4 figure