We verify that the total angular momentum 3-vector defined by the author [X. Zhang, Commun. Math.Phys. 206 (1999) 137] is equal to (0, 0, ma) forany time slice in both the Kerr and the Kerr-Newman spacetimes.
As an inherent degree of freedom,total angular momentum(TAM)of photons consisting of spin angular momentum and orbital angular momentum has inspired many advanced applications and attracted much attention in recent ye...As an inherent degree of freedom,total angular momentum(TAM)of photons consisting of spin angular momentum and orbital angular momentum has inspired many advanced applications and attracted much attention in recent years.Probing TAM and tailoring beam’s TAM spectrum on demand are of great significance for TAM-based scenarios.We propose both theoretically and experimentally a TAM processor enabling tunable TAM manipulation.Such a processor consists of a set of quasi-symmetric units,and each unit is composed of a couple of diffraction optical elements fabricated through polymerized liquid crystals.Forty-two single TAM states are experimentally employed to prove the concept.The favorable results illustrate good TAM state selection performance,which makes it particularly attractive for high-speed large-capacity data transmission,optical computing,and high-security photon encryption systems.展开更多
A method of time-frequency analysis (TFA) based on wavelets is applied to study the phase space structure of three-dimensional asymmetric triaxial galaxy enclosed by spherical dark halo component. The investigation is...A method of time-frequency analysis (TFA) based on wavelets is applied to study the phase space structure of three-dimensional asymmetric triaxial galaxy enclosed by spherical dark halo component. The investigation is carried out in the presence and absence of dark halo component. Time-frequency analysis is based on the extraction of instantaneous frequency from the phase of the continuous wavelet transform. This method is comparatively fast and reliable. This method can differentiate periodic from quasi-periodic, chaotic sticky from chaotic non-sticky, ordered from chaotic and also, it can accurately determine the time interval of the resonance trapping and transitions too. Apart from that, the phenomenon of transient chaos can be explained with the help of time-frequency analysis. Comparison with the method of total angular momentum (denoted as Ltot) proposed recently is also presented.展开更多
文摘We verify that the total angular momentum 3-vector defined by the author [X. Zhang, Commun. Math.Phys. 206 (1999) 137] is equal to (0, 0, ma) forany time slice in both the Kerr and the Kerr-Newman spacetimes.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3607700)the National Natural Science Foundation of China(Grant Nos.11834001 and 61905012)+3 种基金the National Defense Basic Scientific Research Program of China(Grant No.JCKY2020602C007)the Beijing Natural Science Foundation(Grant No.1232031)the Special Fund for Basic Scientific Research of Central Universities of China(Grant No.2022CX11006)the National Postdoctoral Program for Innovative Talents(Grant No.BX20190036).
文摘As an inherent degree of freedom,total angular momentum(TAM)of photons consisting of spin angular momentum and orbital angular momentum has inspired many advanced applications and attracted much attention in recent years.Probing TAM and tailoring beam’s TAM spectrum on demand are of great significance for TAM-based scenarios.We propose both theoretically and experimentally a TAM processor enabling tunable TAM manipulation.Such a processor consists of a set of quasi-symmetric units,and each unit is composed of a couple of diffraction optical elements fabricated through polymerized liquid crystals.Forty-two single TAM states are experimentally employed to prove the concept.The favorable results illustrate good TAM state selection performance,which makes it particularly attractive for high-speed large-capacity data transmission,optical computing,and high-security photon encryption systems.
文摘A method of time-frequency analysis (TFA) based on wavelets is applied to study the phase space structure of three-dimensional asymmetric triaxial galaxy enclosed by spherical dark halo component. The investigation is carried out in the presence and absence of dark halo component. Time-frequency analysis is based on the extraction of instantaneous frequency from the phase of the continuous wavelet transform. This method is comparatively fast and reliable. This method can differentiate periodic from quasi-periodic, chaotic sticky from chaotic non-sticky, ordered from chaotic and also, it can accurately determine the time interval of the resonance trapping and transitions too. Apart from that, the phenomenon of transient chaos can be explained with the help of time-frequency analysis. Comparison with the method of total angular momentum (denoted as Ltot) proposed recently is also presented.
