THE ACCELERO-MAGNETIC FIELD, THOMAS PRECESSION AND AN EQUIVALENCE PRINCIPLE FOR SPIN

2001 ◽  
Vol 16 (07) ◽  
pp. 429-440 ◽  
Author(s):  
C. S. UNNIKRISHNAN
Keyword(s):  
Magnetic Field ◽  
Equivalence Principle ◽  
Weak Field ◽  
Physical Interaction ◽  
Precision Spectroscopy ◽  
Field Limit ◽  
Thomas Precession ◽  
Weak Field Limit ◽  
The Magnetic Field ◽  
Precision Test

In the weak field limit of Einstein gravity, there are gravitational analogues of the vector potential and the magnetic field. The equivalence principle guides us to a magnetic-like interaction arising from inertial acceleration. The spin precession due to this accelero-magnetic field is identified as the Thomas precession. Hence the torque that is responsible for the precession of the spin is identified as resulting from a physical interaction with a magnetic-like inertial-field. Once the equivalence principle is assumed to some accuracy, well supported by precision tests, this implies that the average effect of the accelero-magnetic field on a classical or quantum gyroscope is the same as that of the gravito-magnetic field on a gyroscope. Precision spectroscopy of spin-orbit doublets in atoms is hence an indirect high precision test of the existence and properties of the gravito-magnetic field. This also implies that the planned and current experiments will not see any deviations from the predictions of general relativity. This line of thought is extended to a brief discussion on the possibility of formulating an independent equivalence principle for the spin.

scholarly journals Plasma Emission Processes in a Magnetoactive Plasma

1972 ◽  
Vol 25 (4) ◽  
pp. 387 ◽  
Author(s):  
DB Melrose ◽  
WN Sy
Keyword(s):  
Magnetic Field ◽  
Second Harmonic ◽  
Magnetoactive Plasma ◽  
Plasma Waves ◽  
Weak Field ◽  
Type I ◽  
Plasma Emission ◽  
Weak Field Limit ◽  
Electron Cyclotron Waves ◽  
The Magnetic Field

Plasma emission (i.e. emission at about the plasma frequency and twice this frequency) is treated taking into account the effects of the magnetic field on the electron plasma waves, on the conversion processes, and on the escaping radiation. The expected degrees of polarization of the fundamental and second harmonic are calculated in the weak field limit. The results are used to estimate the magnetic field strength B at the 80 MHz level from the observed polarization of type III bursts; the result B < 0�04 G is smaller than previous estimates. The possible importance of electron-cyclotron waves in an application to type I bursts is noted.

scholarly journals STRING PHASE TRANSITIONS IN A STRONG MAGNETIC FIELD

1993 ◽  
Vol 08 (26) ◽  
pp. 2497-2502 ◽  
Author(s):  
S. FERRARA ◽  
M. PORRATI
Keyword(s):  
Magnetic Field ◽  
Infinite Sequence ◽  
Weak Field ◽  
Spin Component ◽  
Field Limit ◽  
Abelian Gauge ◽  
Open Strings ◽  
Weak Field Limit ◽  
Extended Object ◽  
Fermionic String

We consider open strings in an external constant magnetic field H. For an (infinite) sequence of critical values of H an increasing number of (highest spin component) states lying on the first Regge trajectory becomes tachyonic. In the limit of infinite H all these states are tachyons (with a common tachyonic mass) both in the case of the bosonic string and for the Neveu-Schwarz sector of the fermionic string. This result generalizes to extended object the same instability which occurs in ordinary non-Abelian gauge theories. The Ramond states always have positive square masses as is the case for ordinary QED. The weak field limit of the mass spectrum is the same as for a field theory with gyromagnetic ratio gS=2 for all charged spin states. This behavior suggests a phase transition of the string as it has been argued for the ordinary electroweak theory.

scholarly journals Optical properties of magnetized black hole in plasma

2019 ◽  
Vol 49 ◽  
pp. 1960018 ◽  
Author(s):  
Bobomurat Ahmedov ◽  
Bobur Turimov ◽  
Zdeněk Stuchlík ◽  
Arman Tursunov
Keyword(s):  
Magnetic Field ◽  
Gravitational Lensing ◽  
Uniform Magnetic Field ◽  
Compact Object ◽  
Weak Field ◽  
Magnetized Plasma ◽  
Spherically Symmetric ◽  
Field Limit ◽  
Weak Field Limit ◽  
The Individual

We study in the weak field limit the gravitational lensing by spherically symmetric compact object immersed in an asymptotically uniform magnetic field in the presence of plasma and our approach is based on the medium modified Hamiltonian one. We show that the magnetized plasma in the environment of compact object may lead to split of the Einstein cross, creating additional lensed components. Finally we calculate magnification and time delay related to the individual images.

GALACTIC AND ASTROPHYSICAL SIZES FROM SCALAR-TENSOR THEORY OF GRAVITY

2004 ◽  
Vol 13 (02) ◽  
pp. 359-371 ◽  
Author(s):  
GIUSEPPE BASINI ◽  
MARCO RICCI ◽  
FULVIO BONGIORNO ◽  
SALVATORE CAPOZZIELLO
Keyword(s):  
Scalar Field ◽  
Spiral Galaxies ◽  
Weak Field ◽  
Newtonian Potential ◽  
Scalar Tensor Theory ◽  
Field Limit ◽  
Weak Field Limit ◽  
Tensor Theory ◽  
Flat Rotation Curves ◽  
Theory Of Gravity

We investigate the weak-field limit of scalar-tensor theory of gravity and show that results are directly depending on the coupling and self-interaction potential of the scalar field. In particular, corrections are derived for the Newtonian potential. We discuss astrophysical applications of the results, in particular the flat rotation curves of spiral galaxies.

scholarly journals Quantum Faraday Effect in the Universe

2017 ◽  
Vol 45 ◽  
pp. 1760046
Author(s):  
Lídice Cruz Rodríguez ◽  
Aurora Pérez Martínez ◽  
Gabriella Piccinelli ◽  
Elizabeth Rodríguez Querts
Keyword(s):  
Faraday Effect ◽  
Weak Field ◽  
Field Limit ◽  
Self Energy ◽  
Weak Field Limit ◽  
Resonant Behavior ◽  
Degenerate Regime ◽  
The Universe ◽  
Resonant Mechanism ◽  
Recombination Epoch

We study the Quantum Faraday rotation starting from the photon self-energy in the presence of a constant magnetic field. The Faraday angle is calculated in the non-degenerate regime and for weak field limit. Two physical scenarios, possibly characterized by these conditions, are the recombination epoch and the jets originated in pulsars. We discuss the resonant behavior that the Faraday angle exhibits in these scenarios and investigate the possibility of detecting cosmic magnetic fields through this resonant mechanism.

scholarly journals The magnetic field in the dense photodissociation region of DR 21

2020 ◽  
Author(s):  
Atanu Koley ◽  
Nirupam Roy ◽  
Karl M Menten ◽  
Arshia M Jacob ◽  
Thushara G S Pillai ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Zeeman Effect ◽  
Zeeman Splitting ◽  
Weak Field ◽  
Field Energy ◽  
Evolutionary Stage ◽  
Maser Emission ◽  
The Magnetic Field ◽  
Photodissociation Region

Abstract Measuring interstellar magnetic fields is extremely important for understanding their role in different evolutionary stages of interstellar clouds and of star formation. However, detecting the weak field is observationally challenging. We present measurements of the Zeeman effect in the 1665 and 1667 MHz (18 cm) lines of the hydroxyl radical (OH) lines toward the dense photodissociation region (PDR) associated with the compact H ii region DR 21 (Main). From the OH 18 cm absorption, observed with the Karl G. Jansky Very Large Array, we find that the line of sight magnetic field in this region is ∼0.13 mG. The same transitions in maser emission toward the neighbouring DR 21(OH) and W 75S-FR1 regions also exhibit the Zeeman splitting. Along with the OH data, we use [C ii] 158 μm line and hydrogen radio recombination line data to constrain the physical conditions and the kinematics of the region. We find the OH column density to be ∼3.6 × 1016(Tex/25 K) cm−2, and that the 1665 and 1667 MHz absorption lines are originating from the gas where OH and C+ are co-existing in the PDR. Under reasonable assumptions, we find the measured magnetic field strength for the PDR to be lower than the value expected from the commonly discussed density–magnetic field relation while the field strength values estimated from the maser emission are roughly consistent with the same. Finally, we compare the magnetic field energy density with the overall energetics of DR 21’s PDR and find that, in its current evolutionary stage, the magnetic field is not dynamically important.

Weak-field limit

2010 ◽  
pp. 165-208
Author(s):  
Salvatore Capozziello ◽  
Valerio Faraoni
Keyword(s):  
Weak Field ◽  
Field Limit ◽  
Weak Field Limit
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