Review
Quantum Science & Technology
Yiting Liu, Zhi Ma, Lan Luo, Chao Du, Yangyang Fei, Hong Wang, Qianheng Duan, Jing Yang
Summary: This paper provides a survey on magic states, which have been widely studied as resource states for fault-tolerant universal quantum computing. It is found that magic states can combine with Clifford gates to achieve universal quantum computation. However, preparing the magic state with high fidelity and low overhead is a crucial problem for realizing universal quantum computation.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Quantum Science & Technology
Guoming Wang, Sukin Sim, Peter D. Johnson
Summary: Quantum computing is believed to have significant applications in simulating chemistry and materials. However, preparing high-quality approximations of the ground state is a critical challenge. In this work, a method called "ground state boosting" is introduced, which uses a limited-depth quantum circuit to reliably increase the overlap with the ground state. The performance of a specific type of booster is demonstrated through numerical simulations.
Article
Multidisciplinary Sciences
Laird Egan, Dripto M. Debroy, Crystal Noel, Andrew Risinger, Daiwei Zhu, Debopriyo Biswas, Michael Newman, Muyuan Li, Kenneth R. Brown, Marko Cetina, Christopher Monroe
Summary: Quantum error correction encodes information into a larger quantum system to protect it, and fault-tolerant circuits are essential for controlling logical qubits and suppressing errors. Experimental demonstration of fault-tolerant circuits for a Bacon-Shor logical qubit with trapped ion qubits shows significant reductions in error rates in the presence of noise. This indicates the potential of fault-tolerant circuits to enable highly accurate logical primitives in current quantum systems, with the possibility of achieving a stabilized logical qubit through improved gate operations and measurements.
Article
Quantum Science & Technology
Jeongwan Haah, Matthew B. Hastings
Summary: This study presents detailed measurement sequences for magic state distillation protocols, which can suppress arbitrary errors on any part of a protocol assuming errors across qubits are independent. The protocol operates on a two-dimensional square grid by measuring ZZ on horizontal qubit pairs, XX on vertical pairs, and Z, X on single qubits when provided with input magic states.
Article
Quantum Science & Technology
Ben W. Reichardt
Summary: Researchers have extended quantum error-correction techniques to extract multiple syndromes simultaneously without requiring additional qubits. This method is fast, efficient, and adheres to geometric constraints, and in some cases allows error-correction without additional qubits.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Quantum Science & Technology
Kianna Wan, Soonwon Choi, Isaac H. Kim, Noah Shutty, Patrick Hayden
Summary: A fault-tolerant quantum computing scheme has been proposed that can be assembled with a small number of experimental components, potentially reducing the engineering challenges of building a large-scale fault-tolerant quantum computer. The scheme has a threshold of 0.39% for depolarizing noise and the logical error rate decays exponentially in the presence of memory errors. This approach is based on a novel procedure for fault-tolerantly preparing three-dimensional cluster states using a single actively controlled qubit and a pair of delay lines.
Article
Optics
Ning Bao, ChunJun Cao, Vincent Paul Su
Summary: Magic can be distributed nonlocally in many-body entangled states. By using the Bravyi-Kitaev magic state distillation protocol, we find that nonlocal magic is distillable and its distillation outcome can be improved. Spin squeezing can be used to convert nondistillable states into distillable ones. It is important to study a diverse range of entangled inputs that yield magic states with high probability.
Article
Physics, Multidisciplinary
Bartosz Regula, Ludovico Lami, Giovanni Ferrari, Ryuji Takagi
Summary: The study introduces a general method for quantifying resources for continuous-variable quantum systems based on robustness measure, with a direct operational interpretation. It is shown to be a well-behaved resource quantifier applicable to various physically relevant resources, such as optical nonclassicality.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
Shraddha Singh, Andrew S. Darmawan, Benjamin J. Brown, Shruti Puri
Summary: Magic state distillation is a resource-intensive subroutine, and our proposed initialization protocol can reduce resource costs by reducing the error rate of input magic states. By utilizing native gate operations of an underlying qubit architecture, our approach offers substantial advantages in the presence of biased noise.
Article
Astronomy & Astrophysics
Kanato Goto, Tomoki Nosaka, Masahiro Nozaki
Summary: The magic property of quantum states is important for achieving universal quantum computation and is related to the chaotic and integrable nature of the system. The study finds that in the chaotic regime, magic increases with time and eventually stabilizes, while in the integrable regime, magic shows periodic behavior. These results suggest a strong connection between the magic of quantum states and the emergence of spacetime geometry.
Article
Physics, Multidisciplinary
Yotam Shapira, Sapir Cohen, Nitzan Akerman, Ady Stern, Roee Ozeri
Summary: In this study, we enhance the fidelity and robustness of entangling gates in quantum computers by introducing spin-dependent squeezing.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Pei Liu, Ruixia Wang, Jing-Ning Zhang, Yingshan Zhang, Xiaoxia Cai, Huikai Xu, Zhiyuan Li, Jiaxiu Han, Xuegang Li, Guangming Xue, Weiyang Liu, Li You, Yirong Jin, Haifeng Yu
Summary: Quantum-computation architecture based on d-level systems, or qudits, has attracted considerable attention recently due to their enlarged Hilbert space. We report a physical realization of a qudit with up to four embedded levels in a superconducting transmon demonstrating high-fidelity initialization, manipulation, and simultaneous multilevel readout. Moreover, we perform prototypical quantum algorithms and observe outcomes consistent with expectations. Our work will hopefully stimulate further research interest in developing manipulation protocols and efficient applications for quantum processors with qudits.
Article
Quantum Science & Technology
Eesa Nikahd, Morteza Saheb Zamani, Mehdi Sedighi
Summary: Fault-tolerant quantum circuit design can be achieved using a set of transversal gates. However, there is no universal set of transversal gates for quantum error correction codes. This paper proposes two approaches for universal fault-tolerant quantum computation based on code concatenation, which outperform the code concatenation approach in terms of qubit count, code distance, and resource overhead.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Quantum Science & Technology
Sam Cree, Kfir Dolev, Vladimir Calvera, Dominic J. Williamson
Summary: The paper evaluates the usefulness of holographic stabilizer codes for fault-tolerant quantum computing by studying their allowed sets of fault-tolerantly implementable gates. It shows that the set of transversally implementable logical operations is contained in the Clifford group for sufficiently localized logical subsystems. The results are extended to approximate encodings, locality-preserving gates, certain codes with nontrivial centers, and discussions on restrictions within the Clifford hierarchy.
Article
Quantum Science & Technology
Christopher Chamberland, Earl T. Campbell
Summary: This paper introduces a decoder capable of correcting spacelike and timelike errors during lattice-surgery protocols, and computes the logical failure rates of a biased circuit-level noise model for lattice-surgery protocol. It also provides protocols for twist-free lattice surgery and temporally encoded lattice surgery, as well as proposes a layout for a quantum processor that is more efficient for rectangular surface codes.
Article
Multidisciplinary Sciences
Michael Vasmer, Dan E. Browne, Aleksander Kubica
Summary: The proposed error correction procedure based on a cellular automaton, the sweep rule, is applicable to a broad range of codes, particularly the toric code. Numerical benchmarks show that the procedure is robust against measurement errors and insensitive to lattice and noise model details. This work represents a step towards finding simple and high-performance decoding strategies for a wide range of quantum low-density parity-check codes.
SCIENTIFIC REPORTS
(2021)
Article
Computer Science, Information Systems
Simon Burton, Dan Browne
Summary: This paper introduces a new technique for limiting the gates of hypergraph product codes in fault-tolerant quantum computers. It provides a necessary condition on these codes and conjectures that this condition applies to a class of Gallagher codes.
IEEE TRANSACTIONS ON INFORMATION THEORY
(2022)
Article
Quantum Science & Technology
Lingling Lao, Alexander Korotkov, Zhang Jiang, Wojciech Mruczkiewicz, Thomas E. O'Brien, Dan E. Browne
Summary: This work presents two software methods to mitigate parasitic errors in two-qubit gates in quantum computing. The first approach utilizes the Cartan's KAK decomposition and applies single-qubit rotations to counteract parasitic gates without additional overhead. The second approach uses a numerical optimization algorithm to recompile a target unitary into the error-parasitic two-qubit gate plus single-qubit gates. The results show that different approaches have advantages in different error regimes, providing guidance for error mitigation in near-term quantum computers.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Asmae Benhemou, Toonyawat Angkhanawin, Charles S. Adams, Dan E. Browne, Jiannis K. Pachos
Summary: The researchers investigate the generation of quantum gates by allowing Z3 parafermions to interact, achieving universality. They study the form of the nontopological gate that arises through direct short-range interaction of the parafermion edge modes in a Z3 parafermion chain. The interaction gives rise to a dynamical phase gate on the encoded ground space, generating a non-Clifford gate which can be tuned to belong to even levels of the Clifford hierarchy. The researchers propose an experiment that simulates the braiding and dynamical evolutions of the Z3 topological states with Rydberg atom technology.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Multidisciplinary
Thomas R. Scruby, Michael Vasmer, Dan E. Browne
Summary: Stabilizer error correcting codes have the ability to project arbitrary errors to Pauli errors, simplifying the physical error correction process. However, logical non-Clifford operations can introduce additional correlations, and previous studies have shown the existence of nonlocal linking charge phenomena in the context of applying a transversal T gate to the three-dimensional color code.
PHYSICAL REVIEW RESEARCH
(2022)
Proceedings Paper
Computer Science, Hardware & Architecture
Lingling Lao, Dan E. Browne
Summary: Researchers developed a quantum compiler named 2QAN to optimize quantum circuits for 2-local qubit Hamiltonian simulation problems. The compiler uses permutation-aware techniques for qubit routing, gate optimization, and scheduling to minimize compilation overhead and achieves better performance than existing compilers.
PROCEEDINGS OF THE 2022 THE 49TH ANNUAL INTERNATIONAL SYMPOSIUM ON COMPUTER ARCHITECTURE (ISCA '22)
(2022)
Article
Quantum Science & Technology
T. R. Scruby, D. E. Browne, P. Webster, M. Vasmer
Summary: This study develops and simulates an explicit recipe for just-in-time decoding scheme in three-dimensional surface codes, based on recent work by B. Brown. It can implement a transversal CCZ operation between three two-dimensional surface codes in linear time. The study presents detailed bounded-height lattice slices through the three-dimensional codes, which retain the code distance and measurement-error detecting properties while allowing dimension-jumping process to expand from/collapse to two-dimensional surface codes on the slice boundaries. The simulation results show a threshold p(c) similar to 0.1% in all three codes, indicating potential for improvement with decoder optimization.
Proceedings Paper
Computer Science, Hardware & Architecture
Lingling Lao, Prakash Murali, Margaret Martonosi, Dan Browne
Summary: The study aims to balance between application expressivity and calibration overhead in near-term quantum computing systems. By using numerical optimization, NuOp efficiently decomposes application operations into different hardware gate types. Results show that implementing 4-8 types of 2Q gates can achieve similar expressivity as a full continuous gate family while significantly reducing calibration overheads.
2021 ACM/IEEE 48TH ANNUAL INTERNATIONAL SYMPOSIUM ON COMPUTER ARCHITECTURE (ISCA 2021)
(2021)
Article
Physics, Multidisciplinary
Andrew Patterson, Hongxiang Chen, Leonard Wossnig, Simone Severini, Dan Browne, Ivan Rungger
Summary: In the near term, noisy quantum computers require algorithms with low circuit depth and qubit count. Research shows that introducing a smaller circuit ansatz can overcome the limitations of gradient calculation on noisy devices with a large number of parameters. The main effect of noise is to increase the overlap between states as circuit gates are applied, making discrimination more challenging.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Quantum Science & Technology
T. R. Scruby, D. E. Browne
Article
Quantum Science & Technology
Sergey Bravyi, Dan Browne, Padraic Calpin, Earl Campbell, David Gosset, Mark Howard
Article
Optics
Michael Vasmer, Dan E. Browne
Article
Optics
Luciana Henaut, Lorenzo Catani, Dan E. Browne, Shane Mansfield, Anna Pappa
Article
Optics
Lorenzo Catani, Dan E. Browne
Article
Optics
James M. Auger, Hussain Anwar, Mercedes Gimeno-Segovia, Thomas M. Stace, Dan E. Browne
