P. Lederer

Fractional excitations in the Luttinger liquid

We reconsider the spectrum of the Luttinger liquid (LL) usually understood in terms of phonons (density fluctuations), and within the context of bosonization we give an alternative representation in terms of fractional states. This allows to make contact with Bethe Ansatz which predicts similar fractional states. As an example we study the spinon operator in the absence of spin rotational invariance and derive it from first principles: we find that it is not a semion in general; a trial Jastrow wavefunction is also given for that spinon state. Our construction of the new spectroscopy based on fractional states leads to several new physical insights: in the low-energy limit, we find that the

Modulated phases, memory effect and defect density waves in thiourea

S_{z}=0

Dynamic and static exchange enhancement in non magnetic alloys

continuum of gapless spin chains is due to pairs of fractional quasiparticle-quasihole states which are the 1D counterpart of the Laughlin FQHE quasiparticles. The holon operator for the Luttinger liquid with spin is also derived. In the presence of a magnetic field, spin-charge separation is not realized any longer in a LL: the holon and the spinon are then replaced by new fractional states which we are able to describe.

Competition between quantum-liquid and electron-solid phases in intermediate Landau levels

Abstract In this paper, we review a variety of recent experimental and theoretical results on thiourea, a compound known for the richness of its phase diagram. We show that a continuum approach “a la Landau” is particularly well suited to understand the modulated phases and the commensurate lock-ins in this compound. The locked phase of commensurability order 8 is qualitatively and semi-quantitatively well accounted for. The birefringence anomalies which detect this phase are shown to be related to the gradient amplitude coupling term in the free energy. Our analysis allows an order of magnitude estimate for the thermal extension of high commensurability order lock-ins. We conclude that wide steps of commensurability order 29, or 43 cannot be of intrinsic origin, and that their observation by X-ray spectroscopy is due to irradiation defects. We describe, discuss and analyse theoretically the memory effect of nodulated phases, which we ascribe to the condensation of a Defect Density Wave, due to the diffus...

Defect Density Waves in Modulated Systems

Abstract We study the effect of the exchange enhancement on the static and dynamic properties of a non magnetic impurity in a non magnetic metal. The largest effects are expected for frequencies low compared to ϵ F , and should be observable in measurements of neutron inelastic scattering, nuclear relaxation time, Knight shift, static susceptibility, etc.

Conductance of one-dimensional quantum wires

On the basis of energy calculations we investigate the competition between quantum-liquid and electron-solid phases in the Landau levels

Quantised density wave ordering induced by a magnetic field in quasi-one-dimensional conductors in the weak-coupling limit

n=1,2,

On the self-similarity in quantum Hall systems

and 3 as a function of their partial filling factor

Microscopic theory of the reentrant integer quantum Hall effect in the first and second excited Landau levels

\overline{\ensuremath{\nu}}.

Stability of Spin Density Waves in Quasi id Conductors : Application to (TMTSF)2-ClO4

Whereas the quantum-liquid phases are stable only in the vicinity of quantized values of