Polynomial-Time Linear Cross-Entropy Benchmarking for Quantum Fidelity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional linear cross-entropy benchmarking (XEB) is unsuitable for benchmarking more complex quantum circuits, limiting the ability to assess the fidelity of quantum computing devices effectively, especially for deeper and larger circuits that cannot be classically simulated.
Innovation Solution
Polynomial-time linear cross-entropy benchmarking (PXEB) using quantum gates suitable for classical simulation, such as Clifford gates, allows for the measurement of fidelity in quantum computing devices by applying sequences of gates that can be simulated in polynomial time, enabling the determination of a fidelity benchmark through classical simulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional linear cross-entropy benchmarking (XEB) is used, then benchmarking can be performed using shallow quantum circuits, but it is unsuitable for benchmarking more complicated quantum circuits
Solution Approach 1:
The patent changes the parameter of gate selection from arbitrary gates to specifically Clifford gates, which have the property of being simulatable in polynomial time by classical computers. This parameter change enables the benchmarking method to be applied to deeper and more complex quantum circuits while maintaining classical simulability for fidelity calculation, thus resolving the contradiction between circuit complexity and benchmarking applicability
2Measurement precision
If polynomial-time classical simulation is used, then fidelity can be determined for complex circuits, but the gate set is limited to those suitable for classical simulation
Solution Approach 1:
The patent segments the quantum circuit into two parts: Clifford gates that can be classically simulated for fidelity calculation, and potentially other gates for which fidelity is not directly calculated. This segmentation allows the method to work with extended gate sets while maintaining polynomial-time classical simulation capability for the Clifford portion, thus resolving the contradiction between measurement precision and gate set versatility
Data Source
AI summary
Systems and methods are disclosed for benchmarking a set of quantum gates. Consistent with disclosed embodiments, a benchmarking method can include obtaining a sequence of M quantum gates from a group of quantum gates according to a probability distribution. The quantum gates in the group can be capable of polynomial-time classical simulation. The method can further include obtaining an outcome measure by applying the sequence of M quantum gates to N qubits of a quantum computing device and obtaining a probability of obtaining the outcome value given the application of the selected sequence of quantum gates. The probability can be obtained using classical simulation of the selected sequence of quantum gates. A fidelity benchmark for the M quantum gates can be generated based at least in part on the obtained probability.