Figure 3 ,Table 0个

    • Figure 1.  Probing quantum crosstalk via OTOCs in 2D qubit grids. (a) A 2D qubit grid with coupling. (b) The initial perturbation V^ scrambled into non-local qubit lattice. If an additionally perturbed W^ applied before rewinding time and falls within the light cone of V^, the scrambling will be captured by the squared commutator C. (c) A 2D qubit grid without coupling. (d) The initial perturbation V^ remains localized, and the squared commutator C retains a value of 1.

    • Figure 2.  Probing quantum crosstalk via OTOCs in a 2 × 2 four-qubit square. (a) Sketch of a generic a 2 × 2 four-qubit square, where the connecting lines represent tunable couplings. Localization operators W^ and V^ are applied to two specific qubits, respectively. (b) OTOC versus evolution time t for different g/2π = 0, 0.05, 0.1, 0.2 MHz, with V^, W^=σ^z applied at Q0 and Q2, respectively. (c) OTOC versus t for a fixed g/2π = 0.2 MHz with W^ at Q1 or Q2. (d) OTOC versus t with (V^, W^)=(σ^x, σ^x) and (σ^z, σ^z), W^ at Q2, g/2π = 0.2 MHz and 0 MHz, respectively. (e) The inverse of the time at which FZZ reaches the first obvious local minimum τ versus the effective coupling geff. Dots are the simulation results and solid lines are the linear fits to the data.

    • Figure 3.  Discriminating only XX-coupling using OTOCs. (a) ZZ-coupling and XX-coupling tuning with a tunable coupler, where the off-point of XX is at coupler frequency ωc/2π = 4.100 GHz. The off-points of ZZ are at ωc/2π = 3.913 GHz and ωc/2π = 4.175 GHz. (b) FZ0Z1 versus ωc and t. (c) FZ0Z2 versus ωc and t. The red horizontal line indicates XX off-point. FZ0Z1 and FX0X1 versus t with (d) ωc/2π = 4.10 GHz, (e) ωc/2π = 4.175 GHz and (f) ωc/2π = 4.45 GHz. (g)–(i) The corresponding frequency spectra obtained from Fourier transform.