712 research outputs found
Correlated transport and non-Fermi liquid behavior in single-wall carbon nanotubes
We derive the effective low-energy theory for single-wall carbon nanotubes
including the Coulomb interactions among electrons. The generic model found
here consists of two spin-1/2 fermion chains which are coupled by the
interaction. We analyze the theory using bosonization, renormalization-group
techniques, and Majorana refermionization. Several experimentally relevant
consequences of the breakdown of Fermi liquid theory observed here are
discussed in detail, e.g., magnetic instabilities, anomalous conductance laws,
and impurity screening profiles.Comment: 23 pages REVTeX, incl 5 figs, to appear in Europ.Phys.Journal
Comment on ``Enhancement of the Tunneling Density of States in Tomonaga-Luttinger Liquids''
In a recent Physical Review Letter, Oreg and Finkel'stein (OF) have
calculated the electron density of states (DOS) for tunneling into a repulsive
Luttinger liquid close to the location of an impurity. The result of their
calculation is a DOS which is enhanced with respect to the pure system, and
moreover diverging for not too strong repulsion. In this Comment we intend to
show that OF's calculation suffers from a subtle flaw which, being corrected,
results into a DOS not only vanishing at zero frequency but in fact suppressed
in comparison with the DOS of a pure Luttinger liquid.Comment: 1 page, Revte
Interaction induced dimerization in zigzag single wall carbon nanotubes
We derive a low-energy effective model of metallic zigzag carbon nanotubes at
half filling. We show that there are three important features characterizing
the low-energy properties of these systems: the long-range Coulomb interaction,
umklapp scattering and an explicit dimerization generated by interactions. The
ratio of the dimerization induced gap and the Mott gap induced by the umklapp
interactions is dependent on the radius of the nanotube and can drive the
system through a quantum phase transition with SU(2)_1 quantum symmetry. We
consider the physical properties of the phases on either side of this
transition which should be relevant for realistic nanotubes.Comment: 8 pages, 5 figure
Crystal Distortion and the Two-Channel Kondo Effect
We study a simple model of the two-channel Kondo effect in a distorted
crystal. This model is then used to investigate the interplay of the Kondo and
Jahn-Teller effects, and also the Kondo effect in an impure crystal. We find
that the Jahn-Teller interaction modifies the characteristic energy scale of
the system below which non-Fermi-liquid properties of the model become
apparent. The modified energy scale tends to zero as the limit of a purely
static Jahn-Teller effect is approached. We find also that the non-Fermi-liquid
properties of the quadrupolar Kondo effect are not stable against crystal
distortion caused by impurities.Comment: 11 page
Exact solution of the three-boson problem at vanishing energy
A zero range approach is used to model resonant two-body interactions between
three identical bosons. A dimensionless phase parametrizes the three-body
boundary condition while the scattering length enters the Bethe-Peierls
boundary condition. The model is solved exactly at zero energy for any value of
the scattering length, positive or negative. From this solution, an analytical
expression for the rate of three-body recombination to the universal shallow
dimer is extracted.Comment: 12 page
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