Instanton-like Excitations in 2D Fermionic Field Theory
New non-perturbatives excitations in the massless Thirring and Schwinger models are discussed.
hep-th↗
arXiv subjects
I. Schmidt
Publications and source records attributed to I. Schmidt.
Topological Excitations in the Thirring model
The quantization of the massless Thirring model in the light-cone using functional methods is considered. The need to compactify the coordinate $x^-$ in the light-cone spacetime implies that the quantum effective action for left-handed fermions contains excitations similar to abelian instantons produced by composite of left-handed fermions. Right-handed fermions don't have a similar effective action. Thus, quantum mechanically, chiral symmetry must be broken as a result of the topological excitations. The conserved charge associated to the topological states is quantized. Different cases with only fermionic excitations or bosonic excitations or both can occur depending on the boundary conditions and the value of the coupling.
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3-dimensional Rules for Finite-Temperature Loops
We present simple diagrammatic rules to write down Euclidean n-point functions at finite temperature directly in terms of 3-dimensional momentum integrals, without ever performing a single Matsubara sum. The rules can be understood as describing the interaction of the external particles with those of the thermal bath.
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Number of Electrons per Collision as a Quark-Gluon Plasma Signal
We investigate whether the total number of electrons per collision, as a function of beam energy, is a potential quark-gluon-plasma (QGP) signature. At high beam energies, we find that, after experimental removal of the noise induced by Dalitz decays, the number of produced electrons is increased many times fold from the existence of the QGP. The robustness of the potential signal to differing theoretical assumptions makes it an attractive experimental parameter.
hep-ph↗
Melosh Rotation and the Nucleon Tensor Charge
By making use of the effect of the Melosh rotation, we show that one can estimate, in a simple way, the nucleon tensor charge in a relativistic quark model formulated on the light-cone. We discuss the physical significance of our results and compare them with those recently obtained in different phenomenological models.
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Anomaly and Condensate in the Light-Cone Schwinger Model
The axial anomaly and fermion condensate in the light cone Schwinger model are studied following path integral methods. This formalism allows for a simple and direct calculation for these and other vacuum dependent phenomena.
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Path Integral Approach to Two-Dimensional QCD in the Light-Front
Two-dimensional quantum cromodynamics in the light-front frame is studied following hamiltonian methods. The theory is quantized using the path integral formalism and an effective theory similar to the Nambu-Jona Lasinio model is obtained. Confinement in two dimensions is derived analyzing directly the constraints in the path integral.
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