Extended Data Fig. 1: Schematic illustrations of the models discussed.
From: Quantum simulation of an exotic quantum critical point in a two-site charge Kondo circuit
a, The DCK model consists of six effectively independent spinless conduction electron reservoirs (blue for island, red for lead), described by fermionic operators fαγ and cα for α = L, R and γ = l, i. Tunneling occurs at each of the three QPCs controlled by JL,C,R. The island charging energy \({E}_{C}^{\alpha }\) correlates electrons fαi and cα on the same island either side of the metal component (black bar). b, At a TP, Eq. (9) describes the system at low temperatures. The three retained charge states of the two-island structure (denoted \(\left\vert A\right\rangle ,\left\vert B\right\rangle ,\left\vert C\right\rangle\)) are interconverted by QPC tunneling. The frustrated QCP arises when JL = JR = JC ≡ J. The conductive pathway \(\left\vert A\right\rangle \to \left\vert B\right\rangle \to \left\vert C\right\rangle\) corresponds to transport from left lead to right lead, and is illustrated with the blue arrows (the flow is reversed \(\left\vert C\right\rangle \to \left\vert B\right\rangle \to \left\vert A\right\rangle\) by changing the sign of the applied bias voltage).
