Current-current Interaction Research Articles

Spectral and dynamic properties of a 2D Luttinger liquid with current-current interactions

We calculate the Green function, particle-hole susceptibility and Cooper pair susceptibility of a 2D Luttinger liquid that results from an electron gas with long-range current-current interactions. The Haldane bosonization scheme allows this model to be written in terms of boson operators, from which the required fermion operators are constructed. We find weakly decaying power law tails in the spectral function and a Kohn anomaly in the 2kF particle-hole susceptibility, but no divergence in the Cooper amplitude.

Eikonal approximation in the theory of two-dimensional fermions with long-range current-current interactions.

We study the behavior of response functions of two-dimensional (2D) fermions interacting via a long-range transverse gauge field in the eikonal approximation. We observe that an exponentially vanishing wave-function renormalization prevents divergences in the density-density correlation function and the pairing susceptibility. The wave-function renormalization also shows up in a suppression of the dHvA effect. Elaborating on an observation recently made by Ioffe, Lidsky, and Altschuler, we also infer an effective bosonic description which makes it possible to reproduce our eikonal results in terms of free 2D bosons.

Bosonization of current-current interactions

Bosonization of current-current interactions

Eikonal approximation in the theory of two-dimensional fermions with long-range current-current interactions

Eikonal approximation in the theory of two-dimensional fermions with long-range current-current interactions

Conformal- and thermodynamic properties of a family of Thirring-like models

We investigate Thirring-like models containing fermionic and scalar fields propagating in 2-dimensional space-time. The corresponding conformal algebra is studied and we disprove a conjecture relating the finite size effects to the central charge. Some new results concerning the fermionic determinant on the torus with chirally twisted boundary conditions and a chemical potential are presented. In particular we show how the thermodynamics of the Thirring model depends on the current-current interaction.

Non-Fermi-liquid behavior in two dimensions due to long-ranged current-current interactions.

We examine the low-energy behavior of two-dimensional electrons with current-current interactions. The interactions are long range, cannot be screened, and result in anomalies in perturbation theory. In the Hartree-Fock theory, we find an instability of the Landau Fermi-liquid state resulting in «fermion-condensate» states with a high degeneracy of levels at the Fermi energy. This degeneracy may be removed to give a Fermi-liquid state with vanishing Fermi velocity. As an example, we investigate further the Fermi-liquid state with the quasiparticle spectrum e(p)∞(p-pF) 3/2 proposed by Halperin et at

Low-energy properties of two-dimensional fermions with long-range current-current interactions.

We calculate the one-particle Green function of 2D fermions interacting via a long-range transverse gauge field. Its asymptotic low-energy behavior is found within the eikonal expansion which consistently sums the infrared divergent terms given by «maximally crossed diagrams.» Instead of power law corrections to Fermi liquid theory we observe a much stronger singularity which implies a more radical breakdown of Fermi liquid theory than the usual orthogonality catastrophe

Collective excitations in a two-component anyon gas

In this paper, we first briefly introduce a two-component anyon model and present unusual commutation relations between the two components. In the Fermi (or Bose) representation, drawing an electrostatic-field analogy, we found that the three-body interaction between particles can be approximately reduced to a logarithmic interaction. In the random-phase approximation, we calculated the effective interaction and dielectric response function. The effect of screening is to make the effective interaction nonsingular at q=0 and to induce a current-current interaction that does not appear in the original interaction. Finally, we found that there exists a restricted class of plasma excitations in the long-wavelength case.

Striped superconductor undulator scheme

A new microundulator scheme is proposed. Superconductor (SC) material layers are interspaced with ferromagnetic layers composing a striped block (blocks). Electrons from a relativistic beam passing transversally to the layers direction near this striped surface will be deflected periodically due to the interaction with self-induced currents: SC provides repulsion and ferromagnetic layers provide attraction. A gas loading of the order of 1–0.1 Torr would be necessary for space charge neutralisation and for providing pure current-current interaction. Since the interaction strength is proportional to the current itself, rather high beam currents are needed for noticeable beam deflections. As it is shown kA currents would be effective enough. One of the specific features of this scheme is that the undulator factor depends linearly on the beam current. The scheme is analysing from the microundulator design problem point of view.

A CANDIDATE FOR EXACT CONTINUUM DUAL THEORY FOR SCALAR QED3

We discuss a possible exact equivalence of the Abelian Higgs model and a scalar theory of a magnetic vortex field in 2 + 1 dimensions. The vortex model has a current-current interaction and can be viewed as a strong coupling limit of a massive vector theory. The fixed point structure of the theory is discussed and mapped into fixed points of the Higgs model.

Use of summation methods in the calculation of nuclear double beta decay processes.

The use of summation methods, to deal with the calculation of matrix elements involved in the microscopic description of nuclear double beta decay processes, is discussed. The analysis focuses on the accuracy of a procedure which formally expresses the matrix elements of the standard current-current weak interaction, starting from the second-order perturbation treatment of the standard weak Lagrangian, as divergent power series of energy denominators. It is shown that, when properly treated, the summation method leads to results which coincide with the numerical sum of contributions due to virtual intermediate states.

Non-Fermi-liquid behavior in two dimensions due to long-ranged current-current interactions

Non-Fermi-liquid behavior in two dimensions due to long-ranged current-current interactions

Low-energy properties of two-dimensional fermions with long-range current-current interactions

Low-energy properties of two-dimensional fermions with long-range current-current interactions

The equivalence of the SU( N) Yang-Mills theory with a purely fermionic model

We investigate the detailed conditions under which a purely fermionic model with current-current interaction goes over to a renormalizable, asymptotically free SU( N c) gauge theory. We argue that a necessary condition is to require the number of fermions N f > 11 2 N c , but this condition might not be sufficient. We consider the sufficient N c → ∞ limit.

Investigations of pairing in anyon systems.

We investigate pairing instabilities in the Fermi-liquid-like state of a single species of anyons. We describe the anyons as fermions interacting with a Chern-Simons gauge field and consider the weak-coupling limit where their statistics approaches that of fermions. We show that, within the conventional BCS approach, because of induced repulsive Coulomb and current-current interactions, the attractive Aharonov-Bohm interaction is not sufficient to generate a gap in the fermion spectrum.

GAPLESS EDGE EXCITATIONS IN THE FRACTIONAL QUANTUM HALL EFFECT AND CONFORMAL INVARIANCE

We propose the conformal-invariant model for the description of the edge excitations (EE) in the FQH states using field-theoretical construction with current-current interactions. We discuss the classification of the topological orders (TO) of a given model. Using Chern-Simons ~ Wess-Zumino equivalence, we determine the possible types of the excitations in the FQHE — namely, we calculate their charges and statistics.

CONNECTIONS BETWEEN THE QUANTUM HALL EFFECT AND CONFORMAL FIELD THEORY

The quantum Hall effect (QHE) is studied in the context of a conformal field theory (CFT). Winding state vertex operators for an effective field of N "spins" associated with the cyclotron motion of particles are defined. The effective field of spins may be used to define an effective Hamiltonian. This effective Hamiltonian describes the collective motion of the N particles (with coupling κ0) together with a current-current interaction (of strength κ1). Such a system gives rise to a CFT in the large-N limit when κ0=κ1. The Laughlin wave function is derived from this CFT as an N'-point correlation function of winding state vertex operators.

Generalized Toda theories and [formula omitted]-algebras associated with integral gradings : L. Fehér, L. O'Raifeartaigh, P. Ruelle, and I. Tsutsui. Dublin institute for advanced studies, 10 burlington road, dublin 4, ireland; and A. Wipf. Institut für theoretische physik, eidgenössische technische hochschule, hönggerberg, zürich CH-8093, switzerland

We show that the strong coupling phase of the non-Abelian Thirring model is dual to the weakcoupling phase of a system of two WZNW models coupled to each other through a current-current interaction. This latter system is integrable and is related to a perturbed conformal field theory which, in the large |k| limit, has a non-trivial zero of the perturbation-parameter beta function. The non-Abelian Thirring model reduces to a free fermion theory plus a topological field theory at this critical point, which should therefore be identified with the isoscalar Dashen-Frishman conformal point. The relationship with the Gross-Neveu model is discussed.

Macroscopic non-relativistic Ampère EM interactions between current elements reflect the conducting electron accelerations by the ion's electric fields

In the light of the subsequent discovery of atoms and electrons, the empirical current-current interactions discovered by Ampère in 1820 evidently reflect a very simplified model of the collective behaviour of the complex randomly agitated charged current constitutive components individually governed by the Maxwell-Lorentz-Einstein electromagnetic laws. It is shown here that the approximate empirically rediscovered Ampère-Weber laws (justified by Rambaut and Vigier) can also be directly derived from a spherical Fermi distribution of interacting accelerated charged particles, tied to a surprisingly simple model of ion-electron interacting couples constituting current elements.

Some results and ideas on the chiral transition in QED

The chiral transition in QED is compared to that in a fermion model with only a local current-current interaction. The conclusion is that the comparison is very close and that the QED transition is well described by mean-field theory with some evidence, in part from finite-size effects, for logarithmic corrections.