Vacuum polarization tensor in inhomogeneous magnetic fields

Vacuum birefringence in strong inhomogeneous electromagnetic fields

QED in inhomogeneous magnetic fields.

A lower bound is placed on the fermionic determinant of Euclidean quantum electrodynamics in three dimensions in the presence of a smooth, finite–flux, static, unidirectional magnetic field B(r) = (0, 0, B(r)), where B(r) ≥ 0 or B(r) ≤ 0 and r is a point in the xy-plane. Bounds are also obtained for the induced spin for 2 + 1 dimensional QED in the presence of B(r). An upper bound is placed on ...

The polarization tensor for a magnetized vacuum

The exact vacuum polarization 4-tensor in the presence of a static magnetic field is calculated by a method due to Svetozarova and Tsytovich. The Hermitian part of the tensor is explicitly renormalized by Shabad’s diagonalization with respect to tensor indices and the anti-Hermitian part of the tensor is found to be finite and gauge invariant. An alternative method for calculating the vacuum po...

Cosmology with inhomogeneous magnetic fields

We review spacetime dynamics in the presence of large-scale electromagnetic fields and then consider the effects of the magnetic component on perturbations to a spatially homogeneous and isotropic universe. Using covariant techniques, we refine and extend earlier work and provide the magnetohydrodynamic equations that describe inhomogeneous magnetic cosmologies in full general relativity. Speci...

Magnetic resonance imaging in inhomogeneous fields

In this paper, we explain the principles underlying imaging with an inhomogeneous B0-field and show how SNR and SAR considerations place limits on the size of the relative field inhomogeneity. We explore problems of imaging with a background field that varies in both magnitude and direction, both with and without critical points. We give a simple geometric explanation for the difficulties that ...