Related Experiment Video
Updated: Jan 7, 2026
05:39
Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
Published on: August 2, 2019
10.2K
Minimal time robust control for two superconducting qubits.
Niril George1, Joseph L Allen2, Robert Kosut3,4,5
1School of Mathematics and Physics, University of Surrey, Guildford, GU2 7XH, UK. ngeorge99@proton.me.
Scientific Reports
|December 24, 2025
Summary
Robust optimal control strategies enable fast, high-fidelity quantum gates in superconducting systems. These methods maintain accuracy despite system parameter uncertainties, crucial for fault-tolerant quantum computing.
Area of Science:
- Quantum Computing
- Quantum Information Science
- Superconducting Circuits
Background:
- Decoherence limits quantum gate fidelity in superconducting systems.
- Optimal control methods often overlook realistic parameter uncertainties.
Purpose of the Study:
- To develop robust optimal control strategies for high-fidelity quantum gates.
- To assess the impact of parameter uncertainties on gate performance.
- To identify minimal control times for experimentally feasible quantum operations.
Main Methods:
- Utilized robust optimal control to design cross-resonance gates.
- Investigated gate performance under varying parameter uncertainties (static and time-dependent).
- Generated control pulses with durations of 64 ns, 71 ns, and 100 ns.
Main Results:
- Achieved high fidelities ([Formula: see text]) with 64 ns gates, robust to 10% parameter uncertainty.
- Attained fidelities ([Formula: see text]) with 71 ns gates, robust to 3% parameter uncertainty.
- Demonstrated 100 ns gates ([Formula: see text]) robust to 10% static error and strong time-dependent noise.
Conclusions:
- Robust optimal control offers a viable open-loop strategy for fast, high-fidelity quantum gates.
- This approach mitigates performance degradation from realistic system uncertainties.
- Results provide guidelines for minimal control times and maximum allowable parameter errors.
Related Concept Videos
01:24BIBO stability of continuous and discrete -time systems
866
System stability is a fundamental concept in signal processing, often assessed using convolution. For a system to be considered bounded-input bounded-output (BIBO) stable, any bounded input signal must produce a bounded output signal. A bounded input signal is one where the modulus does not exceed a certain constant at any point in time.
To determine the BIBO stability, the convolution integral is utilized when a bounded continuous-time input is applied to a Linear Time-Invariant (LTI) system....
To determine the BIBO stability, the convolution integral is utilized when a bounded continuous-time input is applied to a Linear Time-Invariant (LTI) system....
866
01:23Linear time-invariant Systems
839
A system is linear if it displays the characteristics of homogeneity and additivity, together termed the superposition property. This principle is fundamental in all linear systems. Linear time-invariant (LTI) systems include systems with linear elements and constant parameters.
The input-output behavior of an LTI system can be fully defined by its response to an impulsive excitation at its input. Once this impulse response is known, the system's reaction to any other input can be...
The input-output behavior of an LTI system can be fully defined by its response to an impulsive excitation at its input. Once this impulse response is known, the system's reaction to any other input can be...
839
01:21Linear Approximation in Time Domain
314
Nonlinear systems often require sophisticated approaches for accurate modeling and analysis, with state-space representation being particularly effective. This method is especially useful for systems where variables and parameters vary with time or operating conditions, such as in a simple pendulum or a translational mechanical system with nonlinear springs.
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length,...
314
01:07Time-Domain Interpretation of PD Control
345
Proportional-Derivative (PD) control is a widely used control method in various engineering systems to enhance stability and performance. In a system with only proportional control, common issues include high maximum overshoot and oscillation, observed in both the error signal and its rate of change. This behavior can be divided into three distinct phases: initial overshoot, subsequent undershoot, and gradual stabilization.
Consider the example of control of motor torque. Initially, a positive...
Consider the example of control of motor torque. Initially, a positive...
345
01:08Spin–Spin Coupling Constant: Overview
1.4K
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
1.4K
01:24Superconductor
1.7K
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
1.7K