laboratoire pierre aigrain
électronique et photonique quantiques
laboratoire pierre aigrain

Séminaire, 11 février 2013

François Parmentier (LPN, Marcoussis)
Tomonaga-Luttinger physics in electronic quantum circuits

In one-dimensional conductors, Coulomb interactions result in correlated electronic systems called Tomonaga-Luttinger liquids (TLL). The TLL physics also applies to other many-body phenomena, providing complementary viewpoints while benefiting from the powerful TLL framework.
One such phenomenon is the low-energy conductance suppression of a quantum coherent conductor embedded in a dissipative circuit, an effect called dynamical Coulomb blockade. Here we investigate the basic class of mesoscopic circuits constituted by a short single-channel quantum conductor in series with a resistance R. Remarkably, such circuits can be mapped on a TLL of interaction parameter 1/(1+Re2/h), with an impurity. From this mapping, generalized to realistic dissipative circuits, a scaling law for the suppressed conductance is derived at R = h/e2, and small deviations computed for R ≠ h/e2. We find that the scaling law is obeyed by our data for arbitrary quantum channels, emulated by a Ga(Al)As quantum point contact, and by the recent data of H. Mebrahtu et al. [Nature 488, 61 (2012)] obtained using a carbon nanotube.
This demonstrates a highly tunable test-bed for TLL physics, and consolidates a recently proposed phenomenological expression for the conductance of a quantum channel in a linear circuit [FDP et al., Nature Physics 7, 935-938 (2011)].