Dense Measurements for Gate-Model Quantum Computers

The measurement procedure is a fundamental cornerstone of gate-model quantum computers. The main issues in current quantum measurement strategies are the high number of measurement rounds to determine a global optimal measurement output and the low success probability of finding a global optimal measurement output. Each measurement round requires preparing the quantum system and applying quantum operations and measurements with high-precision control in the physical layer. These issues result in high-cost measurements with a low probability of success. Here, we define a novel measurement for gate-model quantum computers called dense quantum measurement. The dense measurement strategy aims at fixing the main drawbacks of standard quantum measurements by achieving a significant reduction in the number of necessary measurement rounds and by radically improving the success probabilities of finding global optimal outputs. We provide application scenarios for quantum circuits with arbitrary unitary sequences. The dense measurement also provides an experimentally implementable solution for practical quantum computations.