Using conformal field theory calculations of the energy spectrum, within XXZ model we investigate effects flux insertion and Umklapp term. We discuss two approaches to evaluation Drude weight, first corresponding linear response second twisted boson with Divergences obtained in context former contradict Bethe ansatz results, coinciding for free fermion point only. The origin this discrepancy is...

2014 Within Landau theory of phase transitions in A2BX4 2014 type crystals we introduce in the free energy a new third-order Umklapp term. In the incommensurate phase this term can induce a new phase transition connected with a rotation of the wave vector of modulation away from the a* direction. The electrostatic energy in these improper ferroelectrics could induce in fact a zig-zag domain-wal...

Lattice thermal conductivity of a quantum well limited by umklapp, impurity, and boundary scattering was investigated theoretically by taking into account dispersion of confined acoustic-phonon modes. We show that strong modification of phonon group velocities due to spatial confinement leads to a significant increase in the phonon relaxation rates. From the numerical calculations, we predict a...

A theory is presented for tunneling between compressible regions on the sides of a narrow incompressible Quantum Hall strip. Assuming that electron interactions lead to formation of a Wigner crystal on the edges of the compressible regions, we consider the situation when the non-conservation of electron momentum required for transport is provided, in the absence of disorder, by umklapp scatteri...

Equilibration of a one-dimensional system of interacting electrons requires processes that change the numbers of left- and right-moving particles. At low temperatures such processes are strongly suppressed, resulting in slow relaxation towards equilibrium. We study this phenomenon in the case of spinless electrons with strong long-range repulsion, when the electrons form a one-dimensional Wigne...

We study the Mott transition in a frustrated Hubbard model with next-nearest neighbor hopping at half-filling. The interplay between interaction, dimensionality, and geometric frustration closes the one-dimensional Mott gap and gives rise to a metallic phase with Fermi surface pockets. We argue that they emerge as a consequence of remnant one-dimensional umklapp scattering at the momenta with v...

The thermal conductivity and thermoelectric power of a single carbon nanotube were measured using a microfabricated suspended device. The observed thermal conductivity is more than 3000 W/K m at room temperature, which is 2 orders of magnitude higher than the estimation from previous experiments that used macroscopic mat samples. The temperature dependence of the thermal conductivity of nanotub...

The interplay of Umklapp scattering from a periodic potential and other scattering processes determine the conductivity of (quasi) one-dimensional metals. We show that the transport at finite temperature is qualitatively and quantitatively strongly influenced by a number of approximate conservation laws. Typically, not the strongest but the second strongest scattering mechanism determines the d...