Fig. 1: Experimental realization.
From: Tunable directional photon scattering from a pair of superconducting qubits
a Schematic showing the scattering direction of the ω ± Ω component for in-phase (up-up) and out-of-phase (up-down) modulation of the qubits' transition frequencies ω. b Optical microscope image and simplified experimental setup. Two transmon qubits are capacitively coupled to a 50 Ω transmission line, and each qubit has a local flux bias line connected to an arbitrary waveform generator channel (AWG), which is used to generate a sinusoidal wave with an amplitude AV that is filtered with a 80 MHz low-pass filter and applied to ground via a 1 kΩ resistor. We use an RF source, analog downconversion and digitization (DIG) to back out the scattering parameters of the device cooled to 10 mK. c Enlarged view of Qubit 2 and local flux bias line inductively coupled to the qubit SQUID. d, e Individually measured and normalized transmission spectra ∣t0∣2 of elastically scattered radiation from Qubit 1(2) with fit to theory (solid line).
