Strong Magnetic Background Research Articles

CP violation and chiral symmetry restoration in the hot linear sigma model in a strong magnetic background

We study the effects of CP violation on the nature of the chiral transition within the linear sigma model with two flavors of quarks. The finite-temperature effective potential containing contributions from nontrivial values for the parameter θ is computed to one loop order and their minima structure is analyzed. Motivated by the possibility of observing the formation of CP-odd domains in high-energy heavy ion collisions, we also investigate the behavior of the effective potential in the presence of a strong magnetic background. We find that the nature of the chiral transition is influenced by both θ and the magnetic field.

Can a strong magnetic background modify the nature of the chiral transition in QCD?

The presence of a strong magnetic background can modify the nature and the dynamics of the chiral phase transition at finite temperature: for high enough magnetic fields, comparable to the ones expected to be created in noncentral high-energy heavy ion collisions at RHIC and the LHC, the original crossover is turned into a first-order transition. We illustrate this effect within the linear sigma model with quarks to one loop in the MS ¯ scheme for N f = 2 .

Chiral transition in a strong magnetic background

The presence of a strong magnetic background can modify the nature and the dynamics of the chiral phase transition at finite temperature. We compute the modified effective potential in the linear sigma model with quarks to one loop in the MS scheme for N{sub f}=2. For fields eB{approx}5m{sub {pi}}{sup 2} and larger a crossover is turned into a weak first-order transition. We discuss possible implications for noncentral heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider and for the primordial QCD transition.

Dynamics of theO(N)model in a strong magnetic background field as a modified noncommutative field theory

In the presence of a strong magnetic field, the effective action of a composite scalar field in a scalar $O(N)$ model is derived using two different methods. First, in the framework of world-line formalism, the 1PI $n$-point vertex function for the composites is determined in the limit of a strong magnetic field. Then, the $n$-point effective action of the composites is calculated in the regime of lowest Landau level dominance. It is shown that in the limit of a strong magnetic field, the results coincide and an effective field theory arises which is comparable with the conventional noncommutative field theory. In contrast to the ordinary case, however, the UV/IR mixing is absent in this modified noncommutative field theory.

Relativistic field theories in a strong magnetic background asnoncommutative field theories

The connection between the dynamics in relativistic field theories in a strong magnetic field and the dynamics of noncommutative field theories (NCFTs) is discussed. It is shown that this connection is rather sophisticated. In fact, the corresponding NCFTs are different from the conventional ones considered in the literature. In particular, the UV/IR mixing is absent in these theories. The reason for this is an inner structure (i.e., dynamical form factors) of neutral composites that plays an important role in providing consistency for NCFTs. NCFTs could find interesting applications in condensed-matter systems and string theories. PACS Nos.: 11.10.Nx, 11.30.Qc, 11.30.Rd

A new method in mineral magnetism for the separation of weak antiferromagnetic signal from a strong ferrimagnetic background

This paper describes a new magnetic method for determining the contribution of weakly magnetic hematite against a strongly magnetic (e.g. magnetite) background. The method involves measurements of Mfr, a residual or “final” remanence after hysteretic demagnetization of saturated isothermal remanent magnetization. In terms of sensitivity and precision, our proposed method is superior to the currently popular approach known as the HIRM method. Compared to the latter, Mfr has no error amplification caused by subtraction of terms. The method utilizes the available software for hysteretic demagnetization function on an automated vibrating sample magnetometer (VSM). This, in turn, automatically decreases some of the disturbing effects of the strong magnetic background, e.g., magnetic viscosity, initially non‐zero offset of HIRM for partially oxidized magnetite, etc.