scholarly journals Timing of the Binary Pulsar B1259–63

2004 ◽  
Vol 218 ◽  
pp. 429-430
Author(s):  
N. Wang ◽  
S. Johnston ◽  
R. N. Manchester
Keyword(s):  
Major Axis ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Semi Major Axis ◽  
Timing Behavior ◽  
Binary Pulsar ◽  
Orbital Parameters ◽  
Secular Changes ◽  
Period Variations

This paper summarizes the results of 13 years of timing observations of a unique binary pulsar, B1259–63, which has a massive B2e star companion. A small glitch in the pulsar period apparently occurred in 1997 Aug, not long after the 1997 periastron. We found that spin-orbit coupling with secular changes in periastron longitude and projected semi-major axis cannot account for the observed period variations. A model in which step changes in pulsar orbital parameters occur at each periastron accounts best for the observed timing behavior.

scholarly journals The Green Bank Northern Celestial Cap Pulsar Survey. VI. Discovery and Timing of PSR J1759+5036: A Double Neutron Star Binary Pulsar

2021 ◽  
Vol 922 (1) ◽  
pp. 35
Author(s):  
G. Y. Agazie ◽  
M. G. Mingyar ◽  
M. A. McLaughlin ◽  
J. K. Swiggum ◽  
D. L. Kaplan ◽  
...  
Keyword(s):  
Neutron Star ◽  
Major Axis ◽  
Total System ◽  
Semi Major Axis ◽  
Binary Pulsar ◽  
Orbital Parameters ◽  
Spin Period ◽  
Timing Data ◽  
Star Binary ◽  
Radio Transients

Abstract The Green Bank North Celestial Cap survey is a 350 MHz all-sky survey for pulsars and fast radio transients using the Robert C. Byrd Green Bank Telescope. To date, the survey has discovered over 190 pulsars, including 33 millisecond pulsars and 24 rotating radio transients. Several exotic pulsars have been discovered in the survey, including PSR J1759+5036, a binary pulsar with a 176 ms spin period in an orbit with a period of 2.04 days, an eccentricity of 0.3, and a projected semi-major axis of 6.8 light seconds. Using seven years of timing data, we are able to measure one post–Keplerian parameter, advance of periastron, which has allowed us to constrain the total system mass to 2.62 ± 0.03 M ⊙. This constraint, along with the spin period and orbital parameters, suggests that this is a double neutron star system, although we cannot entirely rule out a pulsar-white dwarf binary. This pulsar is only detectable in roughly 45% of observations, most likely due to scintillation. However, additional observations are required to determine whether there may be other contributing effects.

scholarly journals Classical Spin-Orbit Coupling and Periastron Advance in PSR J0045–7319

1996 ◽  
Vol 160 ◽  
pp. 531-532
Author(s):  
Victoria M. Kaspi
Keyword(s):  
Direct Evidence ◽  
Supernova Explosion ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Classical Spin ◽  
Binary Pulsar ◽  
Angular Momenta ◽  
Orbital Decay ◽  
First Time

AbstractRadio timing observations of the SMC binary pulsar PSR J0045–7319 show, for the first time in a binary pulsar, that classical spin-orbit coupling and periastron advance are occurring. From the observations, the angle θ between the B star spin axis and the orbital angular momentum is constrained to be 25° < θ < 41° (Kaspi et al. 1996b). Under the conventional assumption that the pre-supernova angular momenta were aligned, this provides direct evidence for an asymmetric supernova explosion. In addition, a large, unexpected orbital decay is observed in the system.

scholarly journals Observation of chiral surface excitons in a topological insulator Bi2Se3

2019 ◽  
Vol 116 (10) ◽  
pp. 4006-4011 ◽  
Author(s):  
H.-H. Kung ◽  
A. P. Goyal ◽  
D. L. Maslov ◽  
X. Wang ◽  
A. Lee ◽  
...  
Keyword(s):  
Polarized Light ◽  
Orbit Coupling ◽  
Experimental Investigations ◽  
Composite Particles ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Excitation Energies ◽  
Circularly Polarized Light ◽  
Pl Emission ◽  
Strong Spin

The protected electron states at the boundaries or on the surfaces of topological insulators (TIs) have been the subject of intense theoretical and experimental investigations. Such states are enforced by very strong spin–orbit interaction in solids composed of heavy elements. Here, we study the composite particles—chiral excitons—formed by the Coulomb attraction between electrons and holes residing on the surface of an archetypical 3D TI,Bi2Se3. Photoluminescence (PL) emission arising due to recombination of excitons in conventional semiconductors is usually unpolarized because of scattering by phonons and other degrees of freedom during exciton thermalization. On the contrary, we observe almost perfectly polarization-preserving PL emission from chiral excitons. We demonstrate that the chiral excitons can be optically oriented with circularly polarized light in a broad range of excitation energies, even when the latter deviate from the (apparent) optical band gap by hundreds of millielectronvolts, and that the orientation remains preserved even at room temperature. Based on the dependences of the PL spectra on the energy and polarization of incident photons, we propose that chiral excitons are made from massive holes and massless (Dirac) electrons, both with chiral spin textures enforced by strong spin–orbit coupling. A theoretical model based on this proposal describes quantitatively the experimental observations. The optical orientation of composite particles, the chiral excitons, emerges as a general result of strong spin–orbit coupling in a 2D electron system. Our findings can potentially expand applications of TIs in photonics and optoelectronics.

Spin–orbit coupling driven novel magnetism in d 5 6H-perovskite iridates Ba3IrTi2O9 and Ba3TiIr2O9

2019 ◽  
Vol 31 (18) ◽  
pp. 185802 ◽  
Author(s):  
Sayantika Bhowal ◽  
Shreemoyee Ganguly ◽  
Indra Dasgupta
Keyword(s):  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit

scholarly journals Dzyaloshinskii–Moriya interaction in noncentrosymmetric superlattices

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Woo Seung Ham ◽  
Abdul-Muizz Pradipto ◽  
Kay Yakushiji ◽  
Kwangsu Kim ◽  
Sonny H. Rhim ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Degrees Of Freedom ◽  
Orbit Coupling ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Band Formation ◽  
Research Activities ◽  
Moriya Interaction

AbstractDzyaloshinskii–Moriya interaction (DMI) is considered as one of the most important energies for specific chiral textures such as magnetic skyrmions. The keys of generating DMI are the absence of structural inversion symmetry and exchange energy with spin–orbit coupling. Therefore, a vast majority of research activities about DMI are mainly limited to heavy metal/ferromagnet bilayer systems, only focusing on their interfaces. Here, we report an asymmetric band formation in a superlattices (SL) which arises from inversion symmetry breaking in stacking order of atomic layers, implying the role of bulk-like contribution. Such bulk DMI is more than 300% larger than simple sum of interfacial contribution. Moreover, the asymmetric band is largely affected by strong spin–orbit coupling, showing crucial role of a heavy metal even in the non-interfacial origin of DMI. Our work provides more degrees of freedom to design chiral magnets for spintronics applications.

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