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Overcoming the Zero-Rate Hashing Bound with Holographic quantum Error Correction

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arXiv 2024年

作者： Fan, Junyu Steinberg, Matthew Jahn, Alexander Cao, Chunjun Feld, Sebastian QuTech Delft University of Technology Delft2628 CJ Netherlands Quantum and Computer Engineering Department Delft University of Technology Delft2628 CD Netherlands Department of Physics Freie Universität Berlin Berlin14195 Germany Department of Physics Virginia Tech BlacksburgVA24061 United States

A crucial insight for practical quantum error correction is that different types of errors, such as single-qubit Pauli operators, typically occur with different probabilities. Finding an optimal quantum code under such biased noise is a challenging problem, related to finding the (generally unknown) maximum capacity of the corresponding noisy channel. A benchmark for this capacity is given by the hashing bound, describing the performance of random stabilizer codes, which leads to the challenge of finding codes that reach or exceed this bound while also being efficiently decodable. In this work, we show that asymptotically zero-rate holographic codes, built from hyperbolic tensor networks that model holographic bulk/boundary dualities, fulfill both conditions. Of the five holographic code models considered, all are found to reach the hashing bound in some bias regime and one, the holographic surface-code fragment, appears to even exceed the capacity of previously known codes in the 2-Pauli-dominated noise regime. In addition, we consider Clifford deformations that allow all considered codes to reach the hashing bound for 1-Pauli-dominated noise as well. Our results thus establish that holographic codes, which were previously shown to possess efficient tensor-network decoders, also exhibit competitive thresholds under biased noise. Copyright © 2024, The Authors. All rights reserved.

关键词： Tensors

SpinQ: Compilation strategies for scalable spin-qubit architectures

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arXiv 2023年

作者： Paraskevopoulos, Nikiforos Sebastiano, Fabio Almudever, Carmen G. Feld, Sebastian Quantum and Computer Engineering Department Delft University of Technology Delft2628 CD Netherlands QuTech Delft University of Technology Delft2628 CJ Netherlands Computer Engineering Department Universitat Politècnica de València Camino de Vera s/n València46022 Spain

Despite NISQ devices being severely constrained, hardware- and algorithm-aware quantum circuit mapping techniques have been developed to enable successful algorithm executions. Not so much attention has been paid to mapping and compilation implementations for spin-qubit quantum processors due to the scarce availability of experimental devices and their small sizes. However, based on their high scalability potential and their rapid progress it is timely to start exploring solutions on such devices. In this work, we discuss the unique mapping challenges of a scalable crossbar architecture with shared control and introduce SpinQ, the first native compilation framework for scalable spin-qubit architectures. At the core of SpinQ is the Integrated Strategy that addresses the unique operational constraints of the crossbar while considering compilation scalability and obtaining a O(n) computational complexity. To evaluate the performance of SpinQ on this novel architecture, we compiled a broad set of well-defined quantum circuits and performed an in-depth analysis based on multiple metrics such as gate overhead, depth overhead, and estimated success probability, which in turn allowed us to create unique mapping and architectural insights. Finally, we propose novel mapping techniques that could increase algorithm success rates on this architecture and potentially inspire further research on quantum circuit mapping for other scalable spin-qubit architectures. Copyright © 2023, The Authors. All rights reserved.

关键词： Mapping

LEGO HQEC: A Software Tool for Analyzing Holographic quantum Codes

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arXiv 2024年

作者： Fan, Junyu Steinberg, Matthew Jahn, Alexander Cao, Chunjun Sarkar, Aritra Feld, Sebastian QuTech Delft University of Technology Delft2628 CJ Netherlands Quantum and Computer Engineering Department Delft University of Technology Delft2628 CD Netherlands Department of Physics Freie Universität Berlin Berlin14195 Germany Department of Physics Virginia Tech BlacksburgVA24061 United States

quantum error correction (QEC) is a crucial prerequisite for future large-scale quantum computation. Finding and analyzing new QEC codes, along with efficient decoding and fault-tolerance protocols, is central to this effort. Holographic codes are a recent class of QEC subsystem codes derived from holographic bulk/boundary dualities. In addition to exploring the physics of such dualities, these codes possess useful QEC properties such as tunable encoding rates, distance scaling competitive with topological codes, and excellent recovery thresholds. To allow for a comprehensive analysis of holographic code constructions, we introduce LEGO HQEC, a software package utilizing the quantum LEGO formalism. This package constructs holographic codes on regular hyperbolic tilings and spawns their stabilizer generators and logical operators for a specified number of seed codes and layers. Three decoders are included: an erasure decoder based on Gaussian elimination;an integer-optimization decoder;and a tensor-network decoder. With these tools, LEGO HQEC thus enables future systematic studies regarding the utility of holographic codes for practical quantum computing. Copyright © 2024, The Authors. All rights reserved.

关键词： quantum computers

Modeling and Experimental Validation of the Intrinsic SNR in Spin Qubit Gate-Based Readout and Its Impacts on Readout Electronics

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arXiv 2023年

作者： Prabowo, Bagas Dijkema, Jurgen Xue, Xiao Sebastiano, Fabio Vandersypen, Lieven M.K. Babaie, Masoud Department of Quantum and Computer Engineering Delft University of Technology GA Delft2600 Netherlands QuTech Delft University of Technology GA Delft2600 Netherlands Kavli Institute of Nanoscience Delft University of Technology GA Delft2600 Netherlands

In semiconductor spin quantum bits (qubits), the radio-frequency (RF) gate-based readout is a promising solution for future large-scale integration, as it allows for a fast, frequency-multiplexed readout architecture, enabling multiple qubits to be read out simultaneously. This paper introduces a theoretical framework to evaluate the effect of various parameters, such as the readout probe power, readout chain’s noise performance, and integration time on the intrinsic readout signal-to-noise ratio (SNR), and thus readout fidelity of RF gate-based readout systems. By analyzing the underlying physics of spin qubits during readout, this work proposes a qubit readout model that takes into account the qubit’s quantum mechanical properties, providing a way to evaluate the trade-offs among the aforementioned parameters. The validity of the proposed model is evaluated by comparing the simulation and experimental results. The proposed analytical approach, the developed model, and the experimental results enable designers to optimize the entire readout chain effectively, thus leading to a faster, lower-power readout system with integrated cryogenic electronics. © 2023, CC BY.

关键词： Signal to noise ratio

Holographic Codes from Hyperinvariant Tensor Networks

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arXiv 2023年

作者： Steinberg, Matthew Feld, Sebastian Jahn, Alexander QuTech Delft University of Technology Delft2628 CJ Netherlands Quantum and Computer Engineering Department Delft University of Technology Delft2628 CD Netherlands Department of Physics Freie Universität Berlin Berlin14195 Germany Institute for Quantum Information and Matter California Institute of Technology PasadenaCA91125 United States

Holographic quantum-error correcting codes are models of bulk/boundary dualities such as the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, where a higher-dimensional bulk geometry is associated with the code’s logical degrees of freedom. Previous discrete holographic codes based on tensor networks have reproduced the general code properties expected from continuum AdS/CFT, such as complementary recovery. However, the boundary states of such tensor networks typically do not exhibit the expected correlation functions of CFT boundary states. In this work, we show that a new class of exact holographic codes, extending the previously proposed hyperinvariant tensor networks into quantum codes, produce the correct boundary correlation functions. This approach yields a dictionary between logical states in the bulk and the critical renormalization group flow of boundary states. Furthermore, these codes exhibit a state-dependent breakdown of complementary recovery as expected from AdS/CFT under small quantum gravity corrections. Copyright © 2023, The Authors. All rights reserved.

关键词： Tensors

Visualizing quantum Circuit Probability estimating computational action for quantum program synthesis

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arXiv 2023年

作者： Bach, Bao Gia Kundu, Akash Acharya, Tamal Sarkar, Aritra Faculty of Computer Science and Engineering Ho Chi Minh City University of Technology Viet Nam Viet Nam Joint Doctoral School Silesian University of Technology Gliwice Poland Institute of Theoretical and Applied Informatics Polish Academy of Sciences Gliwice Poland Independent Researcher Bengaluru India Quantum Machine Learning Research group Quantum Computing Division QuTech Netherlands Quantum Intelligence Research team Department of Quantum & Computer Engineering Delft University of Technology Netherlands

This research applies concepts from algorithmic probability to Boolean and quantum combinatorial logic circuits. A tutorial-style introduction to states and various notions of the complexity of states are presented. Thereafter, the probability of states in the circuit model of computation is defined. Classical and quantum gate sets are compared to select some characteristic sets. The reachability and expressibility in a space-time-bounded setting for these gate sets are enumerated and visualized. These results are studied in terms of computational resources, universality and quantum behavior. The article suggests how applications like geometric quantum machine learning, novel quantum algorithm synthesis and quantum artificial general intelligence can benefit by studying circuit probabilities. © 2023, CC BY-NC-SA.

关键词： Machine learning

Far from Perfect: quantum Error Correction with (Hyperinvariant) Evenbly Codes

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arXiv 2024年

作者： Steinberg, Matthew Fan, Junyu Harris, Robert J. Elkouss, David Feld, Sebastian Jahn, Alexander QuTech Delft University of Technology Delft2628 CJ Netherlands Quantum and Computer Engineering Department Delft University of Technology Delft2628 CD Netherlands ARC Centre for Engineered Quantum Systems School of Mathematics and Physics The University of Queensland St LuciaQLD4072 Australia Networked Quantum Devices Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan Department of Physics Freie Universität Berlin Berlin14195 Germany

We introduce a new class of qubit codes that we call Evenbly codes, building on a previous proposal of hyperinvariant tensor networks. Its tensor network description consists of local, non-perfect tensors describing CSS codes interspersed with Hadamard gates, placed on a hyperbolic {p, q} geometry with even q ≥ 4, yielding an infinitely large class of subsystem codes. We construct an example for a {5, 4} manifold and describe strategies of logical gauge fixing that lead to different rates k/n and distances d, which we calculate analytically, finding distances which range from d = 2 to d ∼ n2/3 in the ungauged case. Investigating threshold performance under erasure, depolarizing, and pure Pauli noise channels, we find that the code exhibits a depolarizing noise threshold of about 19.1% in the code-capacity model and 50% for pure Pauli and erasure channels under suitable gauges. We also test a constant-rate version with k/n = 0.125, finding excellent error resilience (about 40%) under the erasure channel. Recovery rates for these and other settings are studied both under an optimal decoder as well as a more efficient but non-optimal greedy decoder. We also consider generalizations beyond the CSS tensor construction, compute error rates and thresholds for other hyperbolic geometries, and discuss the relationship to holographic bulk/boundary dualities. Our work indicates that Evenbly codes may show promise for practical quantum computing applications. Copyright © 2024, The Authors. All rights reserved.

关键词： Tensors

Universal high-fidelity quantum gates for spin qubits in diamond

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Physical Review Applied 2025年第3期23卷 034052-034052页

作者： H.P. Bartling J. Yun K.N. Schymik M. van Riggelen L.A. Enthoven H.B. van Ommen M. Babaie F. Sebastiano M. Markham QuTech Delft University of Technology PO Box 5046 2600 GA Delft Netherlands Kavli Institute of Nanoscience Delft Delft University of Technology PO Box 5046 2600 GA Delft Netherlands Department of Quantum and Computer Engineering Delft University of Technology 2628 CJ Delft Netherlands Department of Microelectronics Delft University of Technology 2628 CD Delft Netherlands Element Six Fermi Avenue Harwell Oxford Didcot Oxfordshire OX11 0QR United Kingdom

Spins associated to solid-state color centers are a promising platform for investigating quantum computation and quantum networks. Recent experiments have demonstrated multiqubit quantum processors, optical interconnects, and basic quantum error-correction protocols. One of the key open challenges towards larger-scale systems is to realize high-fidelity universal quantum gates. In this work, we design and demonstrate a complete high-fidelity gate set for the two-qubit system formed by the electron and nuclear spin of a nitrogen-vacancy center in diamond. We use gate set tomography (GST) to systematically optimize the gates and demonstrate single-qubit gate fidelities of up to 99.999(1)% and a two-qubit gate fidelity of 99.93(5)%. Our gates are designed to decouple unwanted interactions and can be extended to other electron-nuclear spin systems. The high fidelities demonstrated provide opportunities towards larger-scale quantum processing with color-center qubits.

关键词： Nanocrystals

DeQompile: quantum circuit decompilation using genetic programming for explainable quantum architecture search

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arXiv 2025年

作者： Xie, Shubing Sarkar, Aritra Feld, Sebastian Instituut-Lorentz Leiden University Netherlands Quantum Machine Learning Research Group Quantum Computing Division QuTech Netherlands Department of Quantum & Computer Engineering Delft University of Technology Netherlands

Demonstrating quantum advantage using conventional quantum algorithms remains challenging on current noisy gate-based quantum computers. Automated quantum circuit synthesis via quantum machine learning has emerged as a promising solution, employing trainable parametric quantum circuits to alleviate this. The circuit ansatz in these solutions is often designed through reinforcement learning-based quantum architecture search when the domain knowledge of the problem and hardware are not effective. However, the interpretability of these synthesized circuits remains a significant bottleneck, limiting their scalability and applicability across diverse problem domains. This work addresses the challenge of explainability in quantum architecture search (QAS) by introducing a novel genetic programming-based decompiler framework for reverse-engineering high-level quantum algorithms from low-level circuit representations. The proposed approach, implemented in the open-source tool DeQompile, employs program synthesis techniques, including symbolic regression and abstract syntax tree manipulation, to distill interpretable Qiskit algorithms from quantum assembly language. Validation of benchmark algorithms demonstrates the efficacy of our tool. By integrating the decompiler with online learning frameworks, this research potentiates explainable QAS by fostering the development of generalizable and provable quantum algorithms. © 2025, CC BY-NC-ND.

关键词： Qubits