Southwest Quantum Information and Technology

Noise-resilient quantum control

Presenting Author: Omid Khosravani, Duke University
Contributing Author(s): Jungsan Kim, Kenneth R. Brown, Vahid Tarokh

One of the main obstacles in scaling up quantum computers is the accumulated noise throughout the quantum circuit. Various error-mitigation and quantum error-correction techniques have been proposed to mitigate and correct the noise. However, these techniques often come with substantially resource requirements that are highly sensitive to the infidelity of quantum gates. However, quantum gates are afflicted by various sources of coherent and incoherent noise that are embedded in quantum control as well as the qubit imperfections and the qubit environment which limits quantum gate fidelities. Here we present a theoretical framework as well as experimental demonstration for quantum gates that are insensitive to well-defined sources of noise up to a specified order. We first show how the quantum control problem can be cast into an optimization problem and provide a path integral picture to justify the noise-resilience of our quantum control framework. We then demonstrate our protocol by generating frequency-amplitude-phase modulated pulses to obtain high-fidelity two-qubit gates in a chain of trapped-ions. We model various sources of noise in two-qubit gates with trapped-ions including correlated electric fields, trap potential irregularities, crosstalk, as well as fluctuations in laser amplitude, frequency and phase, and show how they are mitigated within our framework. We finally discuss how our framework can be readily applied to two-qubit gates with superconducting qubits.

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(Session 8 : Friday from 2:15 pm - 2:45 pm)