Astrophysicist Dong Lai thinks that a quantum electrodynamics (QED) effect called “photon metamorphosis” represent unanticipated observations of X-ray polarization from a magnetar, a neutron star with an extreme magnetic field. Lais theory suggests X-ray photons going through the magnetars allured atmosphere can temporarily change into pairs of “virtual” positrons and electrons, leading to differing polarizations for high-energy and low X-rays.
A “stunning impact” predicted by quantum electrodynamics (QED) might provide a description for the bewildering preliminary sightings of polarized X-rays radiating from a magnetar– a kind of neutron star defined by a profoundly powerful magnetic field, according to a Cornell astrophysicist.
The hot and extremely thick remnant of a massive star, geared up with a magnetic field that exceeds Earths by 100 trillion times, was predicted to produce definitely polarized X-rays. This indicates that the radiations electromagnetic field does not vibrate haphazardly but has a preferred direction.
However scientists were shocked when NASAs Imaging X-ray Polarimetry Explorer (IXPE) satellite in 2015 discovered that lower- and higher-energy X-rays were polarized in a different way, with electromagnetic fields oriented at ideal angles to each other.
The phenomenon can be naturally explained as a result of “photon metamorphosis”– a transformation of X-ray photons that has actually been thought but never ever directly observed, said Dong Lai, Ph.D. 94, the Benson Jay Simon 59, MBA 62, and Mary Ellen Simon, M.A. 63, Professor of Astrophysics in the College of Arts and Sciences.
” In this observation of radiation from a faraway celestial item, we see a stunning impact that is a symptom of elaborate, fundamental physics,” Lai stated. “QED is among the most effective physics theories, but it had actually not been tested in such strong electromagnetic field conditions.”
Lai is the author of a recent study released in Proceedings of the National Academy of Sciences.
The research study builds on estimations Lai and Wynn Ho, Ph.D. 03, published 20 years earlier, including observations NASA reported last November of the magnetar 4U 0142 +61, situated 13,000 light-years away in the Cassiopeia constellation.
Quantum electrodynamics, which explains tiny interactions in between photons and electrons, forecasts that as X-ray photons exit the neutron stars thin atmosphere of hot, magnetized gas, or plasma, they go through a phase called vacuum resonance.
There, Lai stated, photons, which have no charge, can temporarily transform into pairs of “virtual” electrons and positrons that are influenced by the magnetars super-strong electromagnetic field even in a vacuum, a process called “vacuum birefringence.” Integrated with an associated procedure, plasma birefringence, conditions are created for the polarity of high-energy X-rays to swing 90 degrees relative to low-energy X-rays, according to Lais analysis.
” You can think about the polarization as two tastes of photons,” he stated. “A photon suddenly converting from one flavor to another– you do not usually see this kind of thing. Its a natural consequence of the physics if you use the theory under these severe conditions.”
The IXPE objective did not see the polarization swing in observations of another magnetar, called 1RXS J170849.0-400910, with an even more powerful electromagnetic field. Lai said thats constant with his computations, which suggest vacuum resonance and photon metamorphosis would occur really deep inside such a neutron star.
Lai said his interpretation of IXPEs observations of the magnetar 4U 0142 +61 assisted constrain its electromagnetic field and rotation, and recommended that its atmosphere was likely composed of partially ionized heavy aspects.
Ongoing research study of X-rays from some of the universes most extreme objects, consisting of neutron stars and great voids, he stated, allows scientists to penetrate the behavior of matter in conditions that cant be reproduced in labs, and contributes to our understanding of the universes beauty and diversity.
” The observations by IXPE have actually opened a new window for studying the surface environment of neutron stars,” Lai stated. “This will lead to new insights into these enigmatic objects.”
Reference: “IXPE detection of polarized X-rays from magnetars and photon mode conversion at QED vacuum resonance” by Dong Lai, 18 April 2023, Proceedings of the National Academy of Sciences.DOI: 10.1073/ pnas.2216534120.