Detection-Based Measurements for Quantum Emulation Devices
S. Andrew Lanham, Brian R. La Cour · 2020
Quantum emulation devices use analog electronic signals to mimic precisely the behavior of a gate-based quantum computer. These devices also introduce the flexibility to choose different detection rules to generate measurement outcomes. Such rules may depend on deterministic decisions rather than the randomized decisions occurring in Born rule-based measurements of true quantum systems. In this paper, we leverage this flexibility in an emulation device to consider implementations of measurement detection rules with better performance than the Born rule. We visit physically-inspired detection strategies such as maximum-energy and threshold detectors, as well the optimal maximum-likelihood detector. We gauge the detectors by how often they successfully produce the correct outcome of a quantum algorithm in the presence of noise, deriving computationally efficient implementations and comparing their probability of error performance to the Born rule detectors. We find that efficient detectors may be defined with significantly better performance than the Born rule detector at comparable signal-to-noise ratios. We also introduce a theoretical performance comparison to a true quantum computing system operating in a generalized depolarizing channel.