Fig. 1: RVB states in a 2 × 2 quantum dot array.
From: Probing resonating valence bonds on a programmable germanium quantum simulator
a False-colored scanning electron micrograph of the Ge quantum dot array. Plunger and barrier gates are colored in blue and green respectively, and the corresponding gate voltages applied on them are labeled. To achieve independent control of the quantum dot potentials and tunnel couplings, virtual plunger and barrier gate voltages are defined (see Supplementary Note 1). Single hole transistors used as charge sensors are colored in yellow. The scale bar corresponds to 100 nm. b Energy diagram corresponding to the Hamiltonian HS. The stars denote the corresponding eigenstates depicted in (c). When the exchange interaction is dominated by horizontal (vertical) pairs, the ground state is \(\left\vert {S}_{x}\right\rangle\) (\(\left\vert {S}_{y}\right\rangle\)), and in our experiments we use this configuration for initialization. Resonating valence bond states appear when Jy = Jx, the eigenstates are the ground state with s-wave symmetry and excited state with d-wave symmetry.
