CREATION OF A WORMHOLE DUE TO NONLINEAR ELECTRODYNAMICS

2002 ◽  
Vol 17 (20) ◽  
pp. 1305-1314 ◽  
Author(s):  
CARLA FONSECA-BARBATTI ◽  
M. NOVELLO ◽  
J. M. SALIM ◽  
REGINA C. ARCURI
Keyword(s):  
Magnetic Field ◽  
Quantum Electrodynamics ◽  
Nonlinear Electrodynamics ◽  
Einstein Field Equations ◽  
Field Equations ◽  
New Class ◽  
Effective Lagrangian ◽  
The One

We obtain a new class of solutions for the Einstein field equations which describe wormholes by using the one-loop effective Lagrangian of quantum electrodynamics. We also show that the derived wormholes can be maintained only by means of a magnetic field.

scholarly journals Friedmann equations for deformed entropic gravity

2020 ◽  
Vol 29 (06) ◽  
pp. 2050042
Author(s):  
Salih Kibaroğlu ◽  
Mustafa Senay
Keyword(s):  
Early Universe ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Frw Universe ◽  
Friedmann Equations ◽  
Entropic Gravity ◽  
The One ◽  
Two Parameters ◽  
Friedmann Robertson Walker

In this study, we investigate the effects of the one- and two-parameters deformed systems on the Friedmann equations of the Friedmann–Robertson–Walker (FRW) universe by using the entropic gravity approach in the framework of the early universe era. We give simplified forms for the deformed Unruh temperature and Einstein field equations for three different deformed systems. Based on these compact equations, we derive the Friedmann equations with the effective gravitational and cosmological terms.

FERMION INDUCED SINGULARITIES IN A NON-RELATIVISTIC EFFECTIVE LAGRANGIAN FOR ELECTROMAGNETISM

1991 ◽  
Vol 05 (09) ◽  
pp. 1419-1436 ◽  
Author(s):  
S. RANDJBAR-DAEMI ◽  
ABDUS SALAM ◽  
J. STRATHDEE
Keyword(s):  
Quantum Electrodynamics ◽  
Relativistic Quantum ◽  
Effective Field ◽  
Landau Levels ◽  
Zero Temperature ◽  
Oscillatory Behaviour ◽  
Simple Derivation ◽  
Effective Lagrangian ◽  
The One ◽  
Background Fields

Effective field theory methods are applied to the study of non-relativistic quantum electrodynamics in a slowly varying electromagnetic background. It is shown that the one-loop effective action has singularities at those values of the background fields which correspond to complete fillings of Landau levels. One immediate result of our work is a simple derivation of the oscillatory behaviour of the energy density magnetization and permittivities, at zero temperature.

scholarly journals Large N external-field quantum electrodynamics

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Felix Karbstein
Keyword(s):  
Electromagnetic Field ◽  
External Field ◽  
Effective Action ◽  
Quantum Electrodynamics ◽  
Strong Field ◽  
Loop Order ◽  
Field Limit ◽  
Effective Lagrangian ◽  
Large N ◽  
The One

Abstract We advocate the study of external-field quantum electrodynamics with N charged particle flavors. Our main focus is on the Heisenberg-Euler effective action for this theory in the large N limit which receives contributions from all loop orders. The contributions beyond one loop stem from one-particle reducible diagrams. We show that specifically in constant electromagnetic fields the latter are generated by the one-loop Heisenberg-Euler effective Lagrangian. Hence, in this case the large N Heisenberg-Euler effective action can be determined explicitly at any desired loop order. We demonstrate that further analytical insights are possible for electric-and magnetic-like field configurations characterized by the vanishing of one of the secular invariants of the electromagnetic field and work out the all-orders strong field limit of the theory.

scholarly journals Exact solutions for compact stars with CFL quark matter

2020 ◽  
Vol 29 (07) ◽  
pp. 2050044 ◽  
Author(s):  
L. S. Rocha ◽  
A. Bernardo ◽  
M. G. B. De Avellar ◽  
J. E. Horvath
Keyword(s):  
Exact Solutions ◽  
Quark Matter ◽  
Dense Matter ◽  
Compact Stars ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Strange Matter ◽  
Mit Bag Model ◽  
Wide Range ◽  
The One

The search for the true ground state of the dense matter remains open since Bodmer, Terazawa and others raised the possibility of stable quark matter, boosted by Witten’s strange matter hypothesis in 1984. Within this proposal, the strange matter is assumed to be composed of [Formula: see text] quarks in addition to the usual [Formula: see text]s and [Formula: see text]s, having an energy per baryon lower than the strangeless counterpart, and even lower than that of nuclear matter. In this sense, neutron stars should actually be strange stars. Later work showed that a paired, symmetric in flavor, color-flavor locked (CFL) state would be preferred to the one without any pairing for a wide range of the parameters (gap [Formula: see text], strange quark mass [Formula: see text] and bag constant B). We use an approximate, yet very accurate, CFL equation-of-state (EoS) that generalizes the MIT bag model to obtain two families of exact solutions for the static Einstein Field Equations (EFE) constructing families of anisotropic compact relativistic objects. In this fashion, we provide exact useful solutions directly connected with microphysics.

scholarly journals Photon polarization tensor in circularly polarized Hermite- and Laguerre-Gaussian beams

2018 ◽  
Vol 33 (07n08) ◽  
pp. 1850044 ◽  
Author(s):  
Felix Karbstein ◽  
Elena A. Mosman
Keyword(s):  
Quantum Electrodynamics ◽  
Field Approximation ◽  
Constant Field ◽  
Polarization Tensor ◽  
Photon Polarization ◽  
Circularly Polarized ◽  
Polarized Beams ◽  
Effective Lagrangian ◽  
Linearly Polarized ◽  
The One

We derive analytical expressions for the photon polarization tensor in circularly polarized Hermite-Gaussian (HG) and Laguerre-Gaussian (LG) beams, complementing the corresponding results for linearly polarized beams obtained recently. As they are based upon a locally constant field approximation of the one-loop Heisenberg–Euler effective Lagrangian for quantum electrodynamics (QED) in constant fields, our results are generically limited to slowly varying electromagnetic fields, varying on spatial (temporal) scales much larger than the Compton wavelength (time) of the electron.

scholarly journals BULK VISCOUS SOLUTIONS TO THE FIELD EQUATIONS AND THE DECELERATION PARAMETER-REVISITED

2002 ◽  
Vol 11 (09) ◽  
pp. 1419-1434 ◽  
Author(s):  
ANIRUDH PRADHAN ◽  
I. AOTEMSHI
Keyword(s):  
Deceleration Parameter ◽  
Gravitational Constant ◽  
Mass Density ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Variable Cosmological Constant ◽  
New Class ◽  
Bulk Viscous Fluid ◽  
Bulk Viscous ◽  
Viscous Solutions

We utilise a form for the Hubble parameter to generate a number of solutions to the Einstein field equations with variable cosmological constant and variable gravitational constant in the presence of a bulk viscous fluid. The Hubble law utilised yields a constant value for the deceleration parameter. A new class of solutions is presented in the Robertson–Walker spacetimes. The coefficient of bulk viscosity is assumed to be a power function of the mass density. For a class of solutions, the deceleration parameter is negative which is consistent with the supernovae Ia observations.

Another Field to the Pot

2020 ◽  
pp. 119-159
Author(s):  
Dean Rickles
Keyword(s):  
Gravitational Field ◽  
Quantum Electrodynamics ◽  
Hybrid Approach ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Covariant Description ◽  
Theory Of Gravitation ◽  
Treat All ◽  
The Impact ◽  
Field Quantization

This chapter focuses on the impact of field quantization methods on the problem of quantum gravity. It is shown that much work after 1930 until mid-century was an exercise in ‘exploring the consequences’ of the Heisenberg-Pauli theory of quantum electrodynamics: understanding the symmetries and the divergences, and attempting to find ways of dealing with both. The goal was very much to treat all fields in much the same way, and so one could also envisage learning about one field from another. However, there was a separate track, superficially similar, though issuing from a desire to have a theory of gravitation more in line with the rest of physics, and in particular one not involving the difficulties of curved, dynamical spacetime. The interaction representation and a desire for a manifestly covariant description played a crucial role in the development of such approaches, and involved a curious borrowing of concepts often associated with canonical approaches. An apparently orthogonal approach developed alongside these later manifestly covariant approaches, involving a hybrid approach retaining a classical gravitational field, albeit still coupled to quantized sources through the Einstein field equations. These were done largely to avoid complications, however, and the conceptual consequences, though hinted at, were not further explored.

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