Silicon quantum processor with robust long-distance qubit couplings

Guilherme Tosi,Vivien Schmitt,Fahd A Mohiyaddin,Stefanie Tenberg,Rajib Rahman,Gerhard Klimeck,Andrea Morello

doi:10.1038/s41467-017-00378-x

Abstract

Practical quantum computers require a large network of highly coherent qubits, interconnected in a design robust against errors. Donor spins in silicon provide state-of-the-art coherence and quantum gate fidelities, in a platform adapted from industrial semiconductor processing. Here we present a scalable design for a silicon quantum processor that does not require precise donor placement and leaves ample space for the routing of interconnects and readout devices. We introduce the flip-flop qubit, a combination of the electron-nuclear spin states of a phosphorus donor that can be controlled by microwave electric fields. Two-qubit gates exploit a second-order electric dipole-dipole interaction, allowing selective coupling beyond the nearest-neighbor, at separations of hundreds of nanometers, while microwave resonators can extend the entanglement to macroscopic distances. We predict gate fidelities within fault-tolerance thresholds using realistic noise models. This design provides a realizable blueprint for scalable spin-based quantum computers in silicon.

Highlights

Practical quantum computers require a large network of highly coherent qubits, interconnected in a design robust against errors
We introduce the design of a large-scale, donor-based silicon quantum processor based upon electric dipole interactions
The electron interacts with the nucleus through the hyperfine coupling A ≈ 117 MHz

Summary

Introduction

Practical quantum computers require a large network of highly coherent qubits, interconnected in a design robust against errors. We present a scalable design for a silicon quantum processor that does not require precise donor placement and leaves ample space for the routing of interconnects and readout devices. We predict gate fidelities within fault-tolerance thresholds using realistic noise models This design provides a realizable blueprint for scalable spin-based quantum computers in silicon. Relaxed requirements on donor placement can be found when using a hyperfine-controlled exchange interaction between electron spin qubits[25], or a slower magnetic dipole-dipole coupling effective at ~30 nm distances[26]. We introduce the design of a large-scale, donor-based silicon quantum processor based upon electric dipole interactions. This processor could be fabricated using existing technology, since it does not require precise donor placement. The whole structure retains the standard silicon MOS materials stack, important for ultimate manufacturability

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