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Related papers: Parallel Quantum Computation and Quantum Codes

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Reducing the circuit depth of quantum circuits is a crucial bottleneck to enabling quantum technology. This depth is inversely proportional to the number of available quantum gates that have been synthesised. Moreover, quantum gate…

Quantum Physics · Physics 2022-12-15 Francesco Preti , Tommaso Calarco , Felix Motzoi

We present a fault-tolerant universal quantum computing architecture based on a code concatenation of biased-noise qubits and the parity architecture. The parity architecture can be understood as an LDPC code tailored specifically to obtain…

Quantum Physics · Physics 2025-12-01 Anette Messinger , Valentin Torggler , Berend Klaver , Michael Fellner , Wolfgang Lechner

In this work, we prove the strongest known lower bounds for QAC$^0$, allowing polynomially many gates and ancillae. Our main results show that: (1) Depth-3 QAC$^0$ circuits cannot compute PARITY, and require $\Omega(\exp(\sqrt{n}))$ gates…

Quantum Physics · Physics 2026-01-21 Malvika Raj Joshi , Avishay Tal , Francisca Vasconcelos , John Wright

Quantum computing (QC) offers a new computing paradigm that has the potential to provide significant speedups over classical computing. Each additional qubit doubles the size of the computational state space available to a quantum…

Quantum Physics · Physics 2022-05-13 Wei Tang , Margaret Martonosi

Quantum computing (QC) introduces a novel mode of computation with the possibility of greater computational power that remains to be exploited - presenting exciting opportunities for high performance computing (HPC) applications. However,…

Usual scenarios of fault-tolerant computation are concerned with the fault-tolerant realization of quantum algorithms that compute classical functions, such as Shor's algorithm for factoring. In particular, this means that input and output…

Quantum Physics · Physics 2025-12-03 Matthias Christandl , Omar Fawzi , Ashutosh Goswami

Quantum annealing processors typically control qubits in unison, attenuating quantum fluctuations uniformly until the applied system Hamiltonian is diagonal in the computational basis. This simplifies control requirements, allowing…

Decoherence -- in the current physical implementations of quantum computers -- makes depth reduction a vital task in quantum-circuit design. Moore and Nilsson (SIAM Journal of Computing, 2001) demonstrated that additional qubits -- known as…

Quantum Physics · Physics 2022-09-26 Jiaqing Jiang , Xiaoming Sun , Shang-Hua Teng , Bujiao Wu , Kewen Wu , Jialin Zhang

Quantum error correction (QEC) is essential for enabling quantum advantages, with decoding as a central algorithmic primitive. Owing to its importance and intrinsic difficulty, substantial effort has been made to QEC decoder design, among…

Quantum Physics · Physics 2026-05-13 Ge Yan , Shanchuan Li , Yuxuan Du

We show how phase and amplitude estimation algorithms can be parallelized. This can reduce the gate depth of the quantum circuits to that of a single Grover operator with a small overhead. Further, we show that for quantum amplitude…

Quantum Physics · Physics 2022-12-19 M. C. Braun , T. Decker , N. Hegemann , S. F. Kerstan

Shallow quantum circuits have attracted increasing attention in recent years, due to the fact that current noisy quantum hardware can only perform faithful quantum computation for a short amount of time. The constant-depth quantum circuits…

Quantum Physics · Physics 2025-11-11 Yangjing Dong , Fengning Ou , Penghui Yao

The quantum convolutional neural network (QCNN) is a promising quantum machine learning (QML) model that is expected to achieve quantum advantages in classically intractable problems. However, the QCNN requires a large number of…

Quantum Physics · Physics 2024-05-07 Koki Chinzei , Quoc Hoan Tran , Kazunori Maruyama , Hirotaka Oshima , Shintaro Sato

Unitary and non-unitary diagonal operators are fundamental building blocks in quantum algorithms with applications in the resolution of partial differential equations, Hamiltonian simulations, the loading of classical data on quantum…

Quantum Physics · Physics 2025-01-22 Julien Zylberman , Ugo Nzongani , Andrea Simonetto , Fabrice Debbasch

The current generation of quantum computing technologies call for quantum algorithms that require a limited number of qubits and quantum gates, and which are robust against errors. A suitable design approach are variational circuits where…

Quantum Physics · Physics 2020-04-10 Maria Schuld , Alex Bocharov , Krysta Svore , Nathan Wiebe

Quantum computing promises a new approach to solving difficult computational problems, and the quest of building a quantum computer has started. While the first attempts on construction were succesful, scalability has never been achieved,…

Quantum Physics · Physics 2014-08-01 Alexandru Paler , Simon J. Devitt , Kae Nemoto , Ilia Polian

In this research, we create a scalable version of the quantum Fourier transform-based arithmetic circuit to perform addition and subtraction operations on N n-bit unsigned integers encoded in quantum registers, and it is compatible with…

Quantum Physics · Physics 2024-11-04 Murat Kurt , Ayda Kaltehei , Azmi Gençten , Selçuk Çakmak

In this introduction we motivate and explain the ``decoding'' and ``subsystems'' view of quantum error correction. We explain how quantum noise in QIP can be described and classified, and summarize the requirements that need to be satisfied…

Quantum Physics · Physics 2007-05-23 E. Knill , R. Laflamme , A. Ashikhmin , H. Barnum , L. Viola , W. H. Zurek

Quantum neural networks represent a new machine learning paradigm that has recently attracted much attention due to its potential promise. Under certain conditions, these models approximate the distribution of their dataset with a truncated…

Quantum Physics · Physics 2023-11-02 Mo Kordzanganeh , Daria Kosichkina , Alexey Melnikov

Quantum Neural Networks (QNNs) offer a promising framework for integrating quantum computing principles into machine learning, yet their practical capabilities and limitations remain insufficiently studied. In this work, we systematically…

Quantum Physics · Physics 2026-03-31 Martyna Czuba , Patrick Holzer , Hein Zay Yar Oo

We introduce deterministic state-transformation protocols between many-body quantum states which can be implemented by low-depth Quantum Circuits (QC) followed by Local Operations and Classical Communication (LOCC). We show that this gives…

Quantum Physics · Physics 2021-11-24 Lorenzo Piroli , Georgios Styliaris , J. Ignacio Cirac