Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Verification of shuttling protocols in crossbar spin qubit architectures

Dávid Pataki, András Pályi

Published Oct 31, 2024• 0 citations
Publisher

Abstract

This notebook contains a verification algorithm for adiabatic qubit shuttling-based routing in the shared-control crossbar architecture, which is used in the manuscript 'Compiling the surface code to crossbar spin qubit architectures'. As inputs, one needs to specify (i) the desired movements of the electrons (qubits) in the array, and (ii) the abstract pulse sequence specifying the gate-voltage changes. Then, the algorithm verifies whether the abstract pulse sequence generates the desired movements. For an L×L crossbar array, assuming periodic boundary conditions, abstract plunger gate voltage values are expected as a list of integer values with length L. This version of the code can handle up to L=13 different plunger gate voltages (implying a unit cell size L×L=13×13), since we use lowercase characters to enumerate the (vertical and horizontal) barrier gates.

DOI
10.5281/zenodo.14041498

Related papers

Compiling the surface code to crossbar spin qubit architectures

Dávid Pataki, András Pályi

Spin qubits in quantum dots provide a promising platform for realizing large-scale quantum processors since they have a small characteristic size of a few tens of nanometers. One difficulty of controlling, e.g., a few thousand qubits on a single chip is the large number of control lines. The crossbar control architecture has been proposed to reduce the number of control lines exploiting shared control among the qubits. Here we compile the surface code cycle to a pulse sequence that can be executed in the crossbar architecture. We decompose the quantum circuits of the stabilizer measurements in terms of native gates of the spin-qubit architecture. We provide a routing and scheduling protocol and construct a gate voltage pulse sequence for the stabilizer measurement cycle. During this protocol, coherent phase errors can occur on idle qubits, due to the operational constraints of the crossbar architecture. We characterize these crosstalk errors during the stabilizer measurement cycle and identify an experimentally relevant parameter regime where the crosstalk errors are below the surface code threshold. Our results provide design guidelines for near-term qubit experiments with crossbar architectures.

arXiv:2412.05425•Physical review. B./Physical review. B•Mar 18, 2025•4 citations

Auxiliary files for Compiling the surface code to crossbar spin qubit architectures

Dávid Pataki, András Pályi

This repository contains the auxiliary files of the manuscript 'Compiling the surface code to crossbar spin qubit architectures'. ZcyclePulseSequence.xlsx: Excel sheet containing the abstract gate voltage and ESR pulse sequence for the surface code Z-cycle. XcyclePulseSequence.xlsx: Excel sheet containing the abstract gate voltage and ESR pulse sequence for the surface code X-cycle. configurationsZ.txt: Text file containing the configurations (electron and plunger configurations) encountered during the Z-cycle shuttling protocol, as rows. This file is an input for the shuttling verification algorithm. shiftsZ.txt: Text file containing the shifts (describing the movement of electrons) of the Z-cycle shuttling protocol, as rows. This file is an input for the shuttling verification algorithm. configurationsX.txt: Text file containing the electron configurations encountered during the X-cycle shuttling protocol. This file is an input for the shuttling verification algorithm. shiftsX.txt: Text file containing the shifts (describing the movement of electrons) of the X-cycle shuttling protocol, as rows. This file is an input for the shuttling verification algorithm. ZcycleMovie.pdf: Document containing a visual representation of the abstract pulse sequence of the surface code Z-cycle (ZcyclePulseSequence.xlsx). XcycleMovie.pdf: Document containing a visual representation of the abstract pulse sequence of the surface code X-cycle (XcyclePulseSequence.xlsx). The code of the shuttling verification algorithm is available here: https://doi.org/10.5281/zenodo.14047331

•Dec 2, 2024•0 citations

A Folded Surface Code Architecture for 2D Quantum Hardware

Zhu Sun, Zhenyu Cai

Qubit shuttling has become an indispensable ingredient for scaling leading quantum computing platforms, including semiconductor spin, neutral-atom, and trapped-ion qubits, enabling both crosstalk reduction and tighter integration of control hardware. Cai et al. (2023) proposed a scalable architecture that employs short-range shuttling to realize effective three-dimensional connectivity on a strictly two-dimensional device. Building on recent advances in quantum error correction, we show that this architecture enables the native implementation of folded surface codes on 2D hardware, reducing the runtime of all single-qubit logical Clifford gates and logical CNOTs within subsets of qubits from $\mathcal{O}(d)$ in conventional surface code lattice surgery to constant time. We present explicit protocols for these operations and demonstrate that access to a transversal $S$ gate reduces the spacetime volume of 8T-to-CCZ magic-state distillation by more than an order of magnitude compared with standard 2D lattice surgery approaches. Finally, we introduce a new "virtual-stack" layout that more efficiently exploits the quasi-three-dimensional structure of the architecture, enabling efficient multilayer routing on these two-dimensional devices.

quant-pharXiv:2601.19823•Jan 28, 2026•0 citations

Generating Shuttling Procedures for Constrained Silicon Quantum Dot Array

Naoto Sato, Tomonori Sekiguchi, Takeru Utsugi +1 more

In silicon quantum computers, a single electron is trapped in a microstructure called a quantum dot, and its spin is used as a qubit. For large-scale integration of qubits, we previously proposed an approach of sharing a control gate in the row or column of a 2-D quantum dot array. In our array, the shuttling of electrons is a useful technique to operate the target qubit independently and avoid crosstalk. However, since the shuttling is also conducted using shared control gates, the movement of qubits is complexly constrained. We, therefore, propose a formal model based on state transition systems to describe those constraints and operation procedures on the array. We also present an approach to generate operation procedures under the constraints. Utilizing this approach, we present a concrete method for our 16 × 8 quantum dot array. By implementing the proposed method as a quantum compiler, we confirmed that it is possible to generate operation procedures in a practical amount of time for arbitrary quantum circuits. We also demonstrated that crosstalk can be avoided by shuttling and that the fidelity in that case is higher than when crosstalk is not avoided.

arXiv:2401.14683•IEEE Transactions on Quantum Engineering•Jan 1, 2025•5 citations

Mapping quantum algorithms in a crossbar architecture

Alejandro Morais Tejerina

In recent years, Quantum Computing has gone from theory to a promising reality, leading to quantum chips that in a near future might be able to exceed the computational power of any current supercomputer. For this to happen, there are some problems that must be overcome. For example, in a quantum processor qubits are usually arranged in a 2D architecture with limited connectivity between them and in which only nearest-neighbour interactions are allowed. This restricts the execution of two-qubit gates and requires qubit to be moved to adjacent positions. Quantum algorithms, which are described as quantum circuits, neglect the quantum chip constraints and therefore cannot be directly executed. This is known as the mapping problem. This thesis focuses on the problem of mapping quantum algorithms into a quantum chip based on spin qubits, called the crossbar architecture. In this project we have developed the required compiler support (mapping) for making quantum circuits executable on the crossbar architecture based on the tools provided by OpenQL. Using this compiler, we have analyzed the mapping overhead of the crossbar architecture and studied how it relates to the characteristics of quantum algorithms. In addition, we have developed a verification program that checks the output of the compiler and provides a visualisation tool for debugging.

•Jan 1, 2019•2 citations

Non-adiabatic quantum control of quantum dot arrays with fixed exchange using Cartan decomposition

David W. Kanaar, Utkan Güngördü, J. P. Kestner

In semiconductor spin qubits which typically interact through short-range exchange coupling, shuttling of spin is a practical way to generate quantum operations between distant qubits. Although the exchange is often tunable through voltages applied to gate electrodes, its minimal value can be significantly large, which hinders the applicability of existing shuttling protocols to such devices, requiring a different approach. In this work, we extend our previous results for double- and triple-dot systems, and describe a method for implementing spin state transfer in long chains of singly occupied quantum dots in a non-adiabatic manner. We make use of Cartan decomposition to break down the interacting problem into simpler problems in a systematic way, and use dynamical invariants to design smooth non-adiabatic pulses that can be implemented in devices with modest control bandwidth. Finally, we discuss the extensibility of our results to directed shuttling of spin states on two-dimensional lattices of quantum dots with fixed coupling. This article is part of the theme issue 'Shortcuts to adiabaticity: theoretical, experimental and interdisciplinary perspectives'.

arXiv:2207.02381•Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences•Nov 6, 2022•3 citations
This notebook contains a verification algorithm for adiabatic qubit shuttling-based routing in the shared-control crossbar architecture, which is used in the manuscript 'Compiling the surface code to crossbar spin qubit architectures'. As inputs, one needs to specify (i) the desired movements of the electrons (qubits) in the array, and (ii) the abstract pulse sequence specifying the gate-voltage changes. Then, the algorithm verifies whether the abstract pulse sequence generates the desired movements. For an L×L crossbar array, assuming periodic boundary conditions, abstract plunger gate voltage values are expected as a list of integer values with length L. This version of the code can handle up to L=13 different plunger gate voltages (implying a unit cell size L×L=13×13), since we use lowercase characters to enumerate the (vertical and horizontal) barrier gates.
Spin qubits in quantum dots provide a promising platform for realizing large-scale quantum processors since they have a small characteristic size of a few tens of nanometers. One difficulty of controlling, e.g., a few thousand qubits on a single chip is the large number of control lines. The crossbar control architecture has been proposed to reduce the number of control lines exploiting shared control among the qubits. Here we compile the surface code cycle to a pulse sequence that can be executed in the crossbar architecture. We decompose the quantum circuits of the stabilizer measurements in terms of native gates of the spin-qubit architecture. We provide a routing and scheduling protocol and construct a gate voltage pulse sequence for the stabilizer measurement cycle. During this protocol, coherent phase errors can occur on idle qubits, due to the operational constraints of the crossbar architecture. We characterize these crosstalk errors during the stabilizer measurement cycle and identify an experimentally relevant parameter regime where the crosstalk errors are below the surface code threshold. Our results provide design guidelines for near-term qubit experiments with crossbar architectures.
This repository contains the auxiliary files of the manuscript 'Compiling the surface code to crossbar spin qubit architectures'. ZcyclePulseSequence.xlsx: Excel sheet containing the abstract gate voltage and ESR pulse sequence for the surface code Z-cycle. XcyclePulseSequence.xlsx: Excel sheet containing the abstract gate voltage and ESR pulse sequence for the surface code X-cycle. configurationsZ.txt: Text file containing the configurations (electron and plunger configurations) encountered during the Z-cycle shuttling protocol, as rows. This file is an input for the shuttling verification algorithm. shiftsZ.txt: Text file containing the shifts (describing the movement of electrons) of the Z-cycle shuttling protocol, as rows. This file is an input for the shuttling verification algorithm. configurationsX.txt: Text file containing the electron configurations encountered during the X-cycle shuttling protocol. This file is an input for the shuttling verification algorithm. shiftsX.txt: Text file containing the shifts (describing the movement of electrons) of the X-cycle shuttling protocol, as rows. This file is an input for the shuttling verification algorithm. ZcycleMovie.pdf: Document containing a visual representation of the abstract pulse sequence of the surface code Z-cycle (ZcyclePulseSequence.xlsx). XcycleMovie.pdf: Document containing a visual representation of the abstract pulse sequence of the surface code X-cycle (XcyclePulseSequence.xlsx). The code of the shuttling verification algorithm is available here: https://doi.org/10.5281/zenodo.14047331
Qubit shuttling has become an indispensable ingredient for scaling leading quantum computing platforms, including semiconductor spin, neutral-atom, and trapped-ion qubits, enabling both crosstalk reduction and tighter integration of control hardware. Cai et al. (2023) proposed a scalable architecture that employs short-range shuttling to realize effective three-dimensional connectivity on a strictly two-dimensional device. Building on recent advances in quantum error correction, we show that this architecture enables the native implementation of folded surface codes on 2D hardware, reducing the runtime of all single-qubit logical Clifford gates and logical CNOTs within subsets of qubits from O(d)\mathcal{O}(d)O(d) in conventional surface code lattice surgery to constant time. We present explicit protocols for these operations and demonstrate that access to a transversal SSS gate reduces the spacetime volume of 8T-to-CCZ magic-state distillation by more than an order of magnitude compared with standard 2D lattice surgery approaches. Finally, we introduce a new "virtual-stack" layout that more efficiently exploits the quasi-three-dimensional structure of the architecture, enabling efficient multilayer routing on these two-dimensional devices.
In silicon quantum computers, a single electron is trapped in a microstructure called a quantum dot, and its spin is used as a qubit. For large-scale integration of qubits, we previously proposed an approach of sharing a control gate in the row or column of a 2-D quantum dot array. In our array, the shuttling of electrons is a useful technique to operate the target qubit independently and avoid crosstalk. However, since the shuttling is also conducted using shared control gates, the movement of qubits is complexly constrained. We, therefore, propose a formal model based on state transition systems to describe those constraints and operation procedures on the array. We also present an approach to generate operation procedures under the constraints. Utilizing this approach, we present a concrete method for our 16 × 8 quantum dot array. By implementing the proposed method as a quantum compiler, we confirmed that it is possible to generate operation procedures in a practical amount of time for arbitrary quantum circuits. We also demonstrated that crosstalk can be avoided by shuttling and that the fidelity in that case is higher than when crosstalk is not avoided.
In recent years, Quantum Computing has gone from theory to a promising reality, leading to quantum chips that in a near future might be able to exceed the computational power of any current supercomputer. For this to happen, there are some problems that must be overcome. For example, in a quantum processor qubits are usually arranged in a 2D architecture with limited connectivity between them and in which only nearest-neighbour interactions are allowed. This restricts the execution of two-qubit gates and requires qubit to be moved to adjacent positions. Quantum algorithms, which are described as quantum circuits, neglect the quantum chip constraints and therefore cannot be directly executed. This is known as the mapping problem. This thesis focuses on the problem of mapping quantum algorithms into a quantum chip based on spin qubits, called the crossbar architecture. In this project we have developed the required compiler support (mapping) for making quantum circuits executable on the crossbar architecture based on the tools provided by OpenQL. Using this compiler, we have analyzed the mapping overhead of the crossbar architecture and studied how it relates to the characteristics of quantum algorithms. In addition, we have developed a verification program that checks the output of the compiler and provides a visualisation tool for debugging.
In semiconductor spin qubits which typically interact through short-range exchange coupling, shuttling of spin is a practical way to generate quantum operations between distant qubits. Although the exchange is often tunable through voltages applied to gate electrodes, its minimal value can be significantly large, which hinders the applicability of existing shuttling protocols to such devices, requiring a different approach. In this work, we extend our previous results for double- and triple-dot systems, and describe a method for implementing spin state transfer in long chains of singly occupied quantum dots in a non-adiabatic manner. We make use of Cartan decomposition to break down the interacting problem into simpler problems in a systematic way, and use dynamical invariants to design smooth non-adiabatic pulses that can be implemented in devices with modest control bandwidth. Finally, we discuss the extensibility of our results to directed shuttling of spin states on two-dimensional lattices of quantum dots with fixed coupling. This article is part of the theme issue 'Shortcuts to adiabaticity: theoretical, experimental and interdisciplinary perspectives'.