Cover Picture: Phys. Status Solidi C 5/2013

A triple quantum dot containing three electrons is a versatile solid‐state system allowing different tuneable qubits by choosing different pairs of the three‐spin levels. S. Studenikin, G. Aers, G. Granger, L. Gaudreau, A. Kam, P. Zawadzki, Z. R. Wasilewski, and A. Sachrajda in their paper on pp. 752–755 demonstrate that disparate qubits and more complex entities can be realized by optimizing the manipulation pulses. The cover figure demonstrates the situation when different pure qubits |1〉 ⟷ |2〉 (blue arrows on the left top inset and the lowest right bottom inset) and |2〉 ⟷ |3〉 (green arrows and the upper right inset) can be realized experimentally, or where all three quantum levels are involved in a coherent process (recently predicted theoretically by Särkkä and Harju [New J. Phys. 13 , 043010‐09 (2011).]). This situation can be considered as a solid‐state qutrit – “a unit of quantum information that can exist in three possible states” (wikipedia).