Fig. 3: TD-QRAM Simulations.
a TD-QRAM access protocol for 12 layers, with the efficiency of generating a Bell pair swept from η = 50% to η = 90%. The noise analysis considers only dephasing and damping errors. The final fidelity is calculated according to Eq. (2), with T1 = 20 ms, T2 = 10 ms, and ϵCNOT = 0 for each layer. b Query times with varying sizes from 2 layers to 12 layers, and sweeping the efficiency of generating a Bell pair from η = 50% to η = 90%. There is an expected logarithmic scaling of the query time with the number of qubits. c TD-QRAM noise analysis with dephasing errors, T2 = 10 ms (filled lines) and T2 = 100 ms (traced lines), with fixed amplitude-damping error T1 = 2 s. We consider different QRAM sizes from 2 layers to 12 layers as well as various efficiencies of generating a Bell pair from η = 50% to η = 90%. d TD-QRAM noise analysis with noisy CNOTs, pe = pn ∈ {0, 10−5, 10−4, 10−3, 10−2}, for a QRAM with the number of layers ranging from 2 to 12. The dephasing time is fixed at T2 = 100 ms, and the amplitude-damping time is fixed at T1 = 2 s. The efficiency of generating a Bell pair is fixed at η = 90%. The final fidelity mainly depends on the number of noisy CNOTs performed throughout the protocol and has little dependence on the efficiency. All the error bars over the data correspond to the error of the average value over 100 simulations of the protocol.
