Randomized Benchmarking: A Quantum Gate Fidelity Measurement Technique

What Randomized Benchmarking Is

Randomized benchmarking (RB) is a technique used to measure the average error rate of quantum gates, which are essential for performing operations on qubits. By applying random sequences of Clifford gates and measuring the survival probability of these operations, RB provides insights into the fidelity of quantum gate implementations.

The method involves generating random sequences of gates that act on a qubit, typically using a set of Clifford gates due to their simplicity and universality in quantum computing. The goal is to quantify how much these operations preserve the state of the qubit over multiple applications.

Why It Happens

The decay in survival probability observed during randomized benchmarking can be attributed to errors introduced by imperfect gate implementations and decoherence. These errors accumulate with each application of a gate, leading to a gradual decrease in the fidelity of the operation.

Decoherence, which is the loss of quantum coherence due to interactions with the environment, also contributes significantly to the error rate. By fitting the decay curve to an exponential function, one can extract the average gate fidelity and assess the overall performance of the quantum hardware.

Applications in Quantum Computing

Randomized benchmarking is crucial for validating the reliability of quantum processors. It helps identify and quantify errors that occur during quantum operations, which is essential for developing error-correcting codes and improving the overall performance of quantum algorithms.

Moreover, RB serves as a benchmarking tool in research and development, allowing scientists to compare different quantum hardware designs and optimize gate sequences to minimize errors.

Real-World Examples

Randomized benchmarking has been applied in various studies of quantum computing systems. For instance, it has been used to assess the performance of superconducting qubits and trapped ion qubits, both of which are leading candidates for large-scale quantum computers.

In addition, RB is employed in the certification process of quantum hardware, ensuring that commercial quantum devices meet the required standards of reliability and accuracy.

Frequently asked questions

Try it live

Everything above runs in your browser — open Randomized Benchmarking: Gate Fidelity Decay (2D) and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.