Programme

O.12 -- Oral, VCTP-51

Date: Tuesday, 4 August 2026

Time: 08:50 - 09:10

Effects of weak electron-electron interactions on transport in a two-site charge Kondo circuit

T. K. T. Nguyen (1), H. Q. Nguyen (1), T. A. Chu (1), and M. N. Kiselev (2)

(1) Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, 118000 Hanoi, Vietnam (2) The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, I-34151, Trieste, Italy

We revisit the double charge Kondo circuit (DCKC), consisting of two charge Kondo circuits weakly coupled via a tunneling junction, as proposed in Phys. Rev. B \textbf{97}, 085403 (2018). We study transport in the presence of Luttinger-liquid correlations characterized by Luttinger parameters $g_1$ and $g_2$, assuming each subsystem realizes a single-channel Kondo setup. Using perturbation theory in the weak-backscattering regime, we analyze thermoelectric response and current fluctuations induced by small temperature and/or voltage biases. All observables exhibit Fermi-liquid-like temperature scaling with exponents determined by an effective Luttinger parameter $g_{eff} = 2g_1 g_2/(g_1 + g_2)$. Interaction asymmetry generates additional contributions to the thermoelectric coefficient and thermopower, a term proportional to $(1/g_1 - 1/g_2)$ that vanishes for $g_1 = g_2$. The thermopower is enhanced with increasing electron-electron interactions at the quantum point contacts (decreasing $g_{eff}$). In contrast, delta-T noise and shot noise are absent for identical CKCs but emerge with electron-electron interaction imbalance, exhibiting an approximately linear dependence on $g_1 - g_2$ and decreasing with increasing interaction strength (decreasing $g_{eff}$). These results establish thermoelectric transport and current fluctuations as sensitive probes of electron-electron interaction asymmetry in DCKCs.

Presenter: Nguyen Thi Kim Thanh