IQIM Postdoctoral and Graduate Student Seminar

Abstract: Quantum sensors and qubits are usually two-level systems (TLS), quantum analogs of classical bits assuming binary values ‘0' or ‘1'. They are useful to the extent to which superpositions of ‘0' and ‘1' persist despite a noisy environment. The standard prescription for long persistence (‘decoherence times') of solid-state qubits is their isolation via extreme ( ppm) dilution in ultra-pure materials. We experimentally demonstrate a different strategy using the rare-earth insulator LiY1-xTbxF4 (x=0.001) which realizes a dense random network of TLS. Some TLS belong to strongly interacting Tb3+ pairs whose quantum states, thanks to localization effects, form highly coherent qubits with 100-fold longer coherence times than single ions. Our understanding of the underlying decoherence mechanisms - and of their suppression - suggests that coherence in networks of dipolar coupled TLS can be enhanced rather than reduced by the interactions.

Lunch will be provided, following the talk, on the lawn north of the Bridge Building.