arXiv:0707.4422 · Physical Review B
Specific heat of a one-dimensional interacting Fermi system: Role of anomalies
Andrey V. Chubukov, Dmitrii L. Maslov, Ronojoy Saha
Abstract
We revisit the issue of the temperature dependence of the specific heat $C(T)$ for interacting fermions in one dimension. 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 renormalization group transformation and eventually behaves as ${g}_{1}(T)\ensuremath{\sim}1∕\mathrm{log}\phantom{\rule{0.2em}{0ex}}T$. We show, however, by direct perturbative calculations that ${C}_{s}(T)$ is strictly linear in $T$ to order ${g}_{1}^{2}$ 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 $2{k}_{F}$. The running amplitude ${g}_{1}(T)$ appears only at third order and gives rise to an extra $T∕{\mathrm{log}}^{3}\phantom{\rule{0.2em}{0ex}}T$ 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.