Devitalizing noise-driven instability of entangling logic in silicon devices with bias controls

Abstract

The quality of quantum bits (qubits) in silicon is highly vulnerable to charge noise that is omni-present in semiconductor devices and is in principle hard to be suppressed. For a realistically sized quantum dot system based on a silicon-germanium heterostructure whose confinement is manipulated with electrical biases imposed on top electrodes, we computationally explore the noise-robustness of 2-qubit entangling operations with a focus on the controlled-X (CNOT) logic that is essential for designs of gate-based universal quantum logic circuits. With device simulations based on the physics of bulk semiconductors augmented with electronic structure calculations, we not only quantify the degradation in fidelity of single-step CNOT operations with respect to the strength of charge noise, but also discuss a strategy of device engineering that can significantly enhance noise-robustness of CNOT operations with almost no sacrifice of speed compared to the single-step case. Details of device designs and controls that this work presents can establish a rare but practical guideline for potential efforts to secure silicon-based quantum processors using an electrode-driven quantum dot platform.

23 pages, 6 figures

References in corpus (6)

• An addressable quantum dot qubit with fault-tolerant control fidelity
• Two-qubit silicon quantum processor with operation fidelity exceeding 99%
• Fast Electrical Control of Single Electron Spins in Quantum Dots with Vanishing Influence from Nuclear Spins
• Robust micro-magnet design for fast electrical manipulations of single spins in quantum dots
• Nonadiabatic holonomic multiqubit controlled gates
• Two-qubit CZ gates robust against charge noise in silicon while compensating for crosstalk using neural network

Cited by in corpus (3)

• Decoherence induced by a sparse bath of two-level fluctuators: peculiar features of $1/f$ noise in high-quality qubits
• A variational quantum algorithm for tackling multi-dimensional Poisson equations with inhomogeneous boundary conditions
• Exploring entanglement resource in Si quantum dot systems with operational quasiprobability approach