Reversable computing, Quantum computers, Quantum theory
Current processes validation methods rely on diverse input states and exponential applications of state tomography. Through generalization of classical test theory exceptions to this rule are found. Instead of expanding a complete operator basis to validate a process, the objective is to utilize quantum effects making each gate realized in the process act on a complete set of characteristic states and next extract functional information. Random noise, systematic errors, initialization inaccuracies and measurement faults must also be detected. This concept is applied to the switching class comprising the search oracle. In a first approach, the test set cardinality is held constant to six; both testability and added depth complexity of an additional ”design-for-test” circuit are related to the function realized in the oracle. Oracles realizing affine functions are shown to generate no net entanglement and are thus the easiest to test, where oracles realizing bent functions are the most difficult to test. A second approach replaces extraction complexity with a linear growth in experiment count. An interesting corollary of this study is the success found when addressing the classical test problem quantum mechanically. The validation of all classical degrees of freedom in a quantum switching network were found to necessitate exponentially fewer averaged observables than the number of tests in the classical lower bound.
Perkowski, Marek and Biamonte, Jacob, "A Quantum Test Algorithm" (2005). Electrical and Computer Engineering Faculty Publications and Presentations. 210.