Ronojoy Saha

Nonanalytic magnetic response of Fermi and non-Fermi liquids

We study the nonanalytic behavior of the static spin susceptibility of two-dimensional fermions as a function of temperature and magnetic field. For a generic Fermi liquid,

Specific heat of a one-dimensional interacting Fermi system : Role of anomalies

{\ensuremath{\chi}}_{s}(T,H)=\mathrm{const}+{c}_{1}\phantom{\rule{0.2em}{0ex}}\mathrm{max}{T,{\ensuremath{\mu}}_{B}\ensuremath{\mid}H\ensuremath{\mid}}

Criticality in inhomogeneous magnetic systems : Application to quantum ferromagnets

, where

Phase-ordering dynamics in itinerant quantum ferromagnets

{c}_{1}

Specific heat of a one-dimensional interacting Fermi system

is shown to be expressed via complicated combinations of the Landau parameters, rather than via the backscattering amplitude, contrary to the case of the specific heat. Near a ferromagnetic quantum critical point, the field dependence acquires a universal form

Nonanalytic Magnetic Response of Fermi- and non-Fermi Liquids

{\ensuremath{\chi}}_{s}^{\ensuremath{-}1}(H)=\mathrm{const}\ensuremath{-}{c}_{2}{\ensuremath{\mid}H\ensuremath{\mid}}^{3∕2}

Signatures of one-dimensional localization of magnetically quantized carriers in graphite: power-law hopping mechanism.

, with

Ferromagnetic quantum phase transition in an itinerant three-dimensional system

{c}_{2}g0

Precursors of 1D behavior for

. This behavior implies a first-order transition into a ferromagnetic state. We establish a criterion for such a transition to win over the transition into an incommensurate phase.

D>1

We re-visit the issue of the temperature dependence of the specific heat C(T) for interacting fermions in 1D. The charge component C_c(T) scales linearly with T, but the spin component C_s (T) displays a more complex behavior with T as it depends on the backscattering amplitude, g_1, which scales down under RG transformation and eventually behaves as g_1 (T) \sim 1/\log T. We show, however, by direct perturbative calculations that C_s(T) is strictly linear in T to order g^2_1 as it contains the renormalized backscattering amplitude not on the scale of T, but at the cutoff scale set by the momentum dependence of the interaction around 2k_F. The running amplitude g_1 (T) appears only at third order and gives rise to an extra T/\log^3 T term in C_s (T). This agrees with the results obtained by a variety of bosonization techniques. We also show how to obtain the same expansion in g_1 within the sine-Gordon model.