Fig. 1: A source of photonic tensor-network states.
From: Deterministic generation of two-dimensional multi-photon cluster states
a Schematic of the entanglement and emission scheme. Couplings are depicted as orange arrows. b False-color micrograph of the device, consisting of source qubits S1 (red) and S2 (blue), emitter qubits E1 and E2 (brown) and tunable couplers C1, C2 and CSS (orange). Common readout (yellow) and emission (purple) lines permit frequency-multiplexed qubit readout and photon emission. c Illustration of the controlled-Z gate (CZ) between two source qubits by driving the \(\vert ee\rangle \leftrightarrow \vert \, fg\rangle\) (orange) sideband transition. Illustration of the physical implementation of (d) the controlled emission (CNOT) of a photon using a π pulse on the \(\vert e\rangle \leftrightarrow \vert \, f\rangle\) manifold (red), the \(\vert \, f0\rangle \leftrightarrow \vert e1\rangle\) sideband transition (orange), and the subsequent decay into the transmission line (purple), and e the emission of a photon via a SWAP operation using the \(\vert e0\rangle \leftrightarrow \vert g1\rangle\) sideband transition (orange). f Quantum circuit used to generate a 2 × n cluster state. Source qubits are denoted as S1 (red), S2 (blue), emitted photonic qubits as Pi. H denotes a Hadamard gate.
