Relativistic Frame Research Articles

Discovery of persistent quasi-periodic oscillations in accreting white dwarfs: a new link to X-ray binaries

ABSTRACT Almost all accreting black hole and neutron star (NS) X-ray binary systems (XRBs) exhibit prominent brightness variations on a few characteristic time-scales and their harmonics. These quasi-periodic oscillations (QPOs) are thought to be associated with the precession of a warped accretion disc, but the physical mechanism that generates the precessing warp remains uncertain. Relativistic frame dragging (Lense–Thirring precession) is one promising candidate, but a misaligned magnetic field is an alternative, especially for NS XRBs. Here, we report the discovery of five accreting white dwarf systems (AWDs) that display strong optical QPOs with characteristic frequencies and harmonic structures that suggest they are the counterpart of the QPOs seen in XRBs. Since AWDs are firmly in the classical (non-relativistic) regime, Lense–Thirring precession cannot account for these QPOs. By contrast, a weak magnetic field associated with the white dwarf can drive disc warping and precession in these systems, similar to what has been proposed for NS XRBs. Our observations confirm that magnetically driven warping is a viable mechanism for generating QPOs in disc-accreting astrophysical systems, certainly in AWDs and possibly also in NS XRBs. Additionally, they establish a new way to estimate magnetic field strengths, even in relatively weak-field systems where other methods are not available.

Global Anisotropies of ΩΛ

An analysis of the cosmological constant ΩΛ fitted to subsamples of the Pantheon+ Type Ia supernova sample spanning 2π steradians for a grid of 432 pole positions covering the whole sky reveals two large-scale asymmetries. One of them is closely aligned with the Galactic north–south direction and the other points approximately toward R.A. ∼ 217.°5, decl. ∼ −26.°4, ∼50.°9 from the cosmic microwave background dipole Apex. The signal-to-noise ratio (S/N) of the multiple ΩΛ measurements in these directions is 3.2 ≲ S/N ≲ 8.4. The first asymmetry is puzzling, and would indicate a systematic effect related with the distribution of Pantheon+ supernovae on the sky and, probably, how the correction for reddening in the Galaxy is calculated. The second one, which entails a 2.8-σ tension between ΩΛ measured in opposite directions, bears strong implications on our interpretation of ΩΛ as dark energy: it is consistent with the prediction for tilted observers located in a Friedmann–Robertson–Walker universe who could measure an acceleration or a deceleration with a dipolar asymmetry, irrespective of what the universe as a whole is doing. In this case, ΩΛ would not be a physical entity, a real dark energy, but an apparent effect associated with the relativistic frame of reference transformation.

Point-charge models and averages for electromagnetic quantities considered in two relativistic inertial frames

Electromagnetic quantities at a spacetime point have tensor Lorentz transformations between relatively-moving inertial frames. However, since the Lorentz transformation of time between inertial frames depends upon both the time and space coordinates, averages of electrodynamic quantities at a single time will in general depend upon the inertial frame, and will differ between inertial frames. Here we illustrate how the use of continuous charge and current distributions rather than point-charge distributions can lead to physically mystifying and even inaccurate results for electromagnetic quantities and physical phenomena. The discrepancy noted between the average electric field values in different inertial frames is particularly striking because it is first order in the relatative velocity between the frames.

A Physical Explanation for the Formation of Auroras

What mechanism causes the symmetrical distribution of two oval-ring auroras approximately around the geomagnetic poles but uneven brightness distribution of them? To answer this question, we firstly describe the charged particles like electrons or protons emitted from the Sun and the magnetic ions formed in the Earth’s atmosphere. Then, the interaction dynamics of two-type particles between electron and ion is given under the non-relativistic limit. Finally, under the relativistic frame, auroras deduced are higher energy density formed by the orthogonal interaction of solar charged particles and geomagnetic ions in the narrow regions centered on the upper geomagnetic poles. The physical nature of ideal oval-ring auroras with uneven brightness distribution is an optical phenomenon that occurs when solar charged particles collide orthogonally with ions and the magnetic axis inclines to the solar radiation. For actual aurora distribution, the impact of multiple factors is discussed. Therefore, the aurora is a natural illustration of an orthogonal collider in the Earth’s upper atmosphere.

Influence of external magnetic field on the electronic structures and radiative properties in plasma-embedded multi-electron atomic systems

A method within the fully relativistic frame, based on the reconstructed Dirac–Coulomb Hamiltonian is suggested which applies to the plasma-embedded multi-electron atomic systems perturbed by applied magnetic fields. The proposal is a configuration interaction method and based upon a combination of two concepts, referred to as plasma screening and external magnetic field. An effective potential, derived by introducing a parameter dependent scaling of the radial dependence of free electron contribution in the ion-sphere, is adopted to model the interactions among the charged particles in dense plasmas, and also the range of external weak magnetic field B<105 T is considered. In this instance, numerical calculations are performed for electronic structures and spectroscopic properties of the He atom and Fe14＋ ion as examples. The accuracy of the present approach is shown by comparison to previous theoretical calculations. The behavior of energies of low excited states and radiative transition probabilities for allowed transitions as a function of the plasma screening and field strength is classified. These results are developed in high energy density physics and astrophysics context.

Entanglement-based measure of non-Makovianity in relativistic frame

We investigate the entanglement-based measure of non-Markovianity of a free Dirac field in a non-inertial frame. We find that the acceleration parameter speeds up the degradation of non-Markovianity from the perspective of entanglement of formation for both amplitude and phase damping environment. On the other hand, the accessible information increases with acceleration show a temporary increase and decrease with finite scaled-time interval, approach to unity in the infinite scaled-time limit for amplitude damping environment in the non-Markovian regime. However, for the phase damping environment, the accessible information temporarily increases and decreases with finite scaled-time intervals, achieving a uniform value (less than one) in the non-Markovian regime. For a given acceleration, the entanglement of formation (accessible information) monotonically decreases (increases) in scaled-time for both amplitude and phase damping channels in the Markovian regime.

The Relativistic Electrodynamics of Classical Charged Particles

Maxwell’s equations and the Lorentz force equation form the foundation of classical electromagnetic theory and their discovery led to the development of special relativity. Despite this achievement, their universal compatibility with the conservation of momentum and relativistic energy transformations is still debated. Incorporating effects of hidden momentum with the Lorentz force equation or using the Einstein–Laub formula are two common approaches to address some of these concerns. Which method to use, or if a change to classical electromagnetism is even required, remains controversial. A new theoretical approach is presented in this paper to address this using relativistic electromagnetic energy inertial frame transformations. These transformations identify a situation where an apparent violation of conservation laws could occur and how to consolidate this with electromagnetic theory. An explanation regarding the elementary nature of magnetism and the relationship between inertia and electromagnetic energy is also commented on.

Quantum speed limit time in a relativistic frame

The evolution of quantum states in a relativistic scenario is a meaningful and practically relevant problem in the framework of quantum physics simulation in a noninertial frame. Here, we investigate the roles of relativistic effect induced by two relatively accelerated bosonic observers on the speed of evolution of a quantum system coupled with amplitude damping channels. We find that the relativistic effect speed-up the quantum evolution of amplitude damped system to a uniform evolution for a damping strength pτ≲pτc0, where pτc0 is a critical damping parameter before which the relativistic effect increases the speed of evolution of the damped system. Moreover, we point out a non-monotonic behavior of the quantum speed limit time (QSLT) with acceleration in the damping limit pτc0≲pτ≲pτc1, where pτc1 is the critical damping parameter beyond which the relativistic effect slows down the speed of evolution of the system. In this range, the relativistic effect first speeds-up and then slows down the quantum evolution process of the damped system. For a damping strength pτc1≲pτ, we observe a monotonic increasing behavior of QSLT, leads to slow down the quantum evolution of the damped system. In addition, we examine the roles of the relativistic effect on the speed limit time for a system coupled with the phase damping channels.

Hydrocode Investigations of Terminal Astroballistics Problems during the Hypothetical Future Planetary Defense System's Space Mission.

The article is devoted to the preliminary concept of the Future Planetary Defense System (FPDS) emphasizing astroballistics. This paper is intended to support international efforts to improve the planetary security of Earth. The work covers three areas of knowledge: astronautics, astrodynamics, and astroballistics. The most important part of the presented article is dynamic, contact combat modeling against small, deformable celestial bodies. For these purposes, the original, proprietary hydrocode of the free particle method (HEFPM-G) with gravity was used. The main aim of combat is to redirect potentially hazardous objects (PHOs) to orbits safe for Earth or destroy them. This concept’s first task is to find, prepare, and use dynamic three-dimensional models of the motion of celestial bodies and spacecraft or human-crewed spaceships in the solar system’s relativistic frame. The second task is to prepare the FPDS’ architecture and computer simulation space missions’ initial concepts in the internal part of the solar system. The third and main task covers simulating, using hydrocodes, and selected methods of fighting 100 m diameter rock material asteroids.

Gravity Probe Spin: Prospects for measuring general-relativistic precession of intrinsic spin using a ferromagnetic gyroscope

An experimental test at the intersection of quantum physics and general relativity is proposed: measurement of relativistic frame dragging and geodetic precession using intrinsic spin of electrons. The behavior of intrinsic spin in spacetime dragged and warped by a massive rotating body is an experimentally open question, hence the results of such a measurement could have important theoretical consequences. Such a measurement is possible by using mm-scale ferromagnetic gyroscopes in orbit around the Earth. Under conditions where the rotational angular momentum of a ferromagnet is sufficiently small, a ferromagnet's angular momentum is dominated by atomic electron spins and is predicted to exhibit macroscopic gyroscopic behavior. If such a ferromagnetic gyroscope is sufficiently isolated from the environment, rapid averaging of quantum uncertainty via the spin-lattice interaction enables readout of the ferromagnetic gyroscope dynamics with sufficient sensitivity to measure both the Lense-Thirring (frame dragging) and de Sitter (geodetic precession) effects due to the Earth.

Comment on “Analyses of M&amp;#246;ssbauer Experiments in a Rotating System: Proper and Improper Approaches” [Annals of Physics Volume 418, July 2020, 168191

The notion of classical well localized trajectories of a single photon in Minkowski spacetime does not make any rigorous sense by the well-known existence of a proof that single photons cannot be well localized. This leads to principal difficultness when photodetection probability on relativistic non inertial frame of reference is considered. In order to resolve this tension, we extend canonical Minkowski geometry up to relevant point-free Minkowski geometry [Ann. Physics 423 (2020) 168329]. The photodetection probability density on uniformly rotating frame endrowed with point-free Lorentzian geometry is obtained. The result of S. A. Podosenov et al. [Ann. Physics 413 (2020) 168047] is obtained without any reference to unphysical notion of the classical trajectories of photon. The paper again shows the correctness of the remarkable result of Prof. C. Corda concerning the Mossbauer rotor experiment as new proof of general relativity, which has been awarded by the Gravity Research Foundation. In addition, the paper also shows various very elementary mistakes, misunderstandings and flaws by the self-called “YARK group”, which is a group of fringe researchers who attempts to promote wrong science, in particular, against the relativity theory.

The Bardeen–Petterson effect in accreting supermassive black hole binaries: a systematic approach

ABSTRACT Disc-driven migration is a key evolutionary stage of supermassive black hole binaries hosted in gas-rich galaxies. Besides promoting the inspiral, viscous interactions tend to align the spins of the black holes with the orbital angular momentum of the disc. We present a critical and systematic investigation of this problem, also known as the Bardeen–Petterson effect. We design a new iterative scheme to solve the non-linear dynamics of warped accretion discs under the influence of both relativistic frame dragging and binary companion. We characterize the impact of the disc ‘critical obliquity’, which marks regions of the parameter space where stationary solutions do not exist. We find that black hole spins reach either complete alignment or a critical configuration. Reaching the critical obliquity might imply that the disc breaks as observed in hydrodynamical simulations. Our findings are important to predict the spin configurations with which supermassive black hole binaries enter their gravitational-wave driven regime and become detectable by LISA.

Electron-impact excitation of ions within a quantum plasma

We develop a new relativistic model which can describe the dynamics on electron-impact excitation (EIE) of ions within a quantum plasma environment. An exemplary excitation 1s1/2 → 2p3/2 of Fe XXVI by electron impact with the exponential cosine-screened Coulomb potential (ECSCP) is presented, i.e., 25 times ionized atoms of Fe, exist in laser-produced plasmas, astrophysical objects, and electron beam ion trap experiments. For the atomic structure of target ion, using the same potential, a Ritz variational method with a trial wave function that contains unknown variational parameters is also proposed for comparison purposes. In this method, an analytical formula of bound energy is derived from the energy equation, and the variational parameters are determined by the minimization of the energy. The energies obtained from our two methods are compared with each other and other theoretical predictions based on the non-relativistic model and found to be in good agreement. For the collision dynamics, the continuum wave function is determined by solving the modified Dirac equations, in which the ECSCP is included for the solution of the continuum orbital. The total cross sections, magnetic sublevel cross sections, and the degrees of linear polarization of emitted x-rays are calculated as a function of the incident energy and screening parameter by using the distorted-wave method in the relativistic frame. Since there are no experiments or other calculations for EIE cross sections on this ion, the obtained results have been compared with those for an isolated ion. The effect of quantum plasma leads to a reduction in the total and magnetic sublevel cross-sections and thus reduces the degrees of linear polarization of emitted x-rays. Comparative analysis allows to estimate the quality of the proposed approximations. Our dynamic model is practicable and easy to apply, which may provide an alternative route towards information with fluorescence polarization in a quantum plasma environment.

The Polarization of X-Rays from Warped Black Hole Accretion Disks

Abstract It is commonly assumed that in black hole (BH) accretion disks the angular momenta of the disk and the BH are aligned. However, for a significant fraction of stellar-mass BHs and supermassive BHs, the momenta may not be aligned. In such systems, the interplay of disk viscosity and general relativistic frame dragging can cause the disk to warp or break into two (or more) distinct planes; this is called the Bardeen–Petterson effect. We have developed a general relativistic ray-tracing code to find the energy spectra and polarization of warped accretion disks, accounting for the emission from the disk and for photons reflecting one or multiple times off the warped accretion disk segments. We find that polarization angle can be used to give a lower limit on the misalignment angle when a previous measurement of the jet, which is thought be aligned with the BH angular momentum, can be spatially resolved.

Ab initio calculations of atomic parameters of Mo XVIII of fusion interest

The relativistic multiconfiguration Dirac–Hartree–Fock (MCDHF) method has been employed to calculate the atomic parameters of Mo XVIII, which are important for fusion determination of plasma properties in different conditions. Atomic data, such as energy levels, lifetimes, wavelengths, spectroscopic labels, and transition rates for the transitions among the lowest 112 states of the 3 s23p63d7, 3 s23p53d8, 3s3 p63d8, and 3s23p63d64s configurations are given. To describe the atomic system accurately, electron correlation effects are taken into account. We also present a calculation within fully relativistic frame based on the Flexible Atomic Code (FAC). This, in turn, allowed us to make an intercomparison on the obtained data. Our two sets of results are also evaluated by comparison with the NIST database recommended values. The new calculated energy levels are, on the average, about 1.5% higher than NIST database recommended values and yield oscillator strengths within 5% of the theoretical values. This study provides a substantial amount of updated atomic data, which are essential for fusion applications.

Protecting Bell correlation via quantum partially collapsing measurement

Quantum correlation is the workhorse of quantum information processing tasks. It is well known that the correlation in open system is unavoidably decayed. Here, we investigate the dynamics of Bell correlation when a bipartite state interacts with a relativistic frame and noisy environment. Based on quantum partially collapsing measurement, we then propose two feasible schemes to protect the degraded Bell correlation and demonstrate that our schemes are valid. At last, we explore the trade-off relation between success probability and measurement strength. The larger the measurement strength, the less probability of success.

Practical theoretical expressions for ions embedded in Debye and quantum plasmas

An accurate theoretical expression is proposed for the atomic structure under external confinement. The analysis is based on the tensor expression for the Breit-Pauli Hamiltonian in which the Racah wave functions are expanded in terms of the linear combinations of the multi-Slater wave functions. The variables are separated into radial and angular parts, where the variational parameters in the trial wave functions are obtained by solving the radial Schrödinger equation and the expressions of the angular part are worked out using an irreducible theory of complex system. Relativistic corrections are derived directly, which are treated as a sum of five terms: mass correction, one-body Darwin correction, two-body Darwin correction, spin-spin contact interaction correction, and orbit-orbit interaction correction. Energies and radiative decay rates of Be-like Fe22+ and Kr32+ ions in the presence of two kinds of plasma environments are presented for demonstration purposes, one is the Debye plasma which is described by a standard Debye-Hückel potential and the other is the quantum plasma which is treated under an exponential cosine screened Coulomb potential. Independent self-consistent calculations within the fully relativistic frame by incorporating the above two potentials are also performed using the Flexible Atomic Code to verify the validity of the proposed expressions. Results are given over a wide range of screening lengths. Relativistic effects in energy spectra are studied for the first time and are found to be rather important, especially in the high-Z system. Comparisons between our two sets of results and other theoretical predictions when available are made. Some behavior of the respective properties with respect to the plasma shielding strength is discussed. The present study should be beneficial for the analysis of spectra in astrophysical and fusion plasmas.

Universal transformation of displacement operators and its application to homodyne tomography in differing relativistic reference frames

In this paper, we study how a displacement of a quantum system appears under a change of relativistic reference frame. We introduce a generic method in which a displacement operator in one reference frame can be transformed into another reference frame. It is found that, when moving between non-inertial reference frames there can be distortions of phase information, modal structure and amplitude. We analyse how these effects affect traditional homodyne detection techniques. We then develop an in principle homodyne detection scheme which is robust to these effect, called the ideal homodyne detection scheme. We then numerically compare traditional homodyne detection with this in principle method and illustrate regimes when the traditional homodyne detection schemes fail to extract full quantum information.

Relativistic quantum reference frames: the operational meaning of spin

Relativistic quantum reference frames: the operational meaning of spin

Nonlocal advantage of quantum coherence under relativistic frame

In this paper, we investigate the influence of the Unruh effect on the achievement of the nonlocal advantage of quantum coherence for a two-qubit system under a relativistic frame. The results show that with the increase of acceleration, it is difficult to realize the nonlocal advantage of quantum coherence and when the acceleration exceeds a certain value, nonlocal advantage of quantum coherence cannot be realized. In addition, we explore the dynamics of Bell nonlocality, steering, quantum coherence, entanglement and quantum discord (QD) under Unruh thermal noise. It is shown that nonlocal advantage of quantum coherence, Bell nonlocality, steering and entanglement experience “sudden death” for a finite acceleration, while quantum coherence and QD vanish only in the limit of an infinite acceleration. We also find that not all nonlocal states can achieve the nonlocal advantage of quantum coherence. It is also demonstrated that the robustness of Bell nonlocality is better than nonlocal advantage of quantum coherence under the influence of the Unruh noise.