Radiative effects in two-dimensional models of quantum electrodynamics in a constant magnetic field

Quantum electrodynamics (QED) in a strong constant magnetic field is investigated from the viewpoint of its connection with noncommutative QED. It turns out that within the lowest Landau level (LLL) approximation the 1-loop contribution of fermions provides an effective action with the noncommutative U(1) NC gauge symmetry. As a result, the Ward identities connected with the initial U(1) gauge symmetry are broken down in the LLL approximation. On the other hand, it is shown that the sum over the infinite number of the higher Landau levels (HLL's) is relevant despite the fact that each contribution of the HLL is suppressed. Owing to this nondecoupling phenomenon the transversality is restored in the whole effective action. The kinematic region where the LLL contribution is dominant is also discussed.

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THE ENTANGLED QUANTUM HEAT ENGINE IN THE VARIOUS HEISENBERG MODELS FOR A TWO-QUBIT SYSTEM

International Journal of Quantum Information ◽

10.1142/s0219749913500214 ◽

2013 ◽

Vol 11 (02) ◽

pp. 1350021 ◽

Cited By ~ 5

Author(s):

ERHAN ALBAYRAK

Keyword(s):

Magnetic Field ◽

Constant Magnetic Field ◽

Heat Engine ◽

Exchange Parameter ◽

Thermodynamic Quantities ◽

Two Dimensional ◽

Quantum Heat Engine ◽

Qubit System ◽

Heisenberg Models ◽

Different Temperatures

The four-level entangled quantum heat engine (QHE) is analyzed in the various Heisenberg models for a two-qubit. The QHE is examined for the XX, XXX and XXZ Heisenberg models by introducing a parameter x which controls the strength of the exchange parameter Jz = xJ along the z-axis with respect to the ones along the x- and y-axes, i.e. Jx = Jy = J, respectively. It is assumed that the two-qubit is entangled and in contact with two heat reservoirs at different temperatures and under the effect of a constant magnetic field. The concurrences (C) are used as a measure of entanglement and then the expressions for the amount of heat transferred, the work performed and the efficiency of the QHE are derived. The contour, i.e. the isoline maps, and some two-dimensional plots of the above mentioned thermodynamic quantities are calculated and some interesting features are found.

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Relaxation of the energy of the two-dimensional Ising model in the absence of an external constant magnetic field

Theoretical and Mathematical Physics ◽

10.1007/bf01018188 ◽

1984 ◽

Vol 59 (2) ◽

pp. 513-519 ◽

Cited By ~ 2

Author(s):

G. O. Berim ◽

R. G. Kamalov

Keyword(s):

Magnetic Field ◽

Ising Model ◽

Constant Magnetic Field ◽

Two Dimensional

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ENERGY SPECTRUM OF THE GROUND STATE OF A TWO-DIMENSIONAL RELATIVISTIC HYDROGEN ATOM IN THE PRESENCE OF A CONSTANT MAGNETIC FIELD

Modern Physics Letters B ◽

10.1142/s0217984903006360 ◽

2003 ◽

Vol 17 (25) ◽

pp. 1331-1341 ◽

Cited By ~ 24

Author(s):

VÍCTOR M. VILLALBA ◽

RAMIRO PINO

Keyword(s):

Magnetic Field ◽

Energy Spectrum ◽

Ground State ◽

Constant Magnetic Field ◽

Two Dimensional ◽

Relativistic Limit ◽

Dirac Electron ◽

Relativistic Hydrogen ◽

Relativistic Hydrogen Atom ◽

The Magnetic Field

We compute the energy spectrum of the ground state of a 2D Dirac electron in the presence of a Coulomb potential and a constant magnetic field perpendicular to the plane where the the electron is confined. With the help of a mixed-basis variational method we compute the wave function and the energy level and show how it depends on the magnetic field strength. We compare the results with those obtained numerically as well as in the non-relativistic limit.

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