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Quantum arithmetic circuits have practical applications in various quantum algorithms. In this paper, we address quantum addition on 2-dimensional nearest-neighbor architectures based on the work presented by Choi and Van Meter (JETC 2012).…

Quantum Physics · Physics 2013-04-02 Mehdi Saeedi , Alireza Shafaei , Massoud Pedram

On today's noisy imperfect quantum devices, execution fidelity tends to collapse dramatically for most applications beyond a handful of qubits. It is therefore imperative to employ novel techniques that can boost quantum fidelity in new…

Due to several physical limitations in the realisation of quantum hardware, today's quantum computers are qualified as Noisy Intermediate-Scale Quantum (NISQ) hardware. NISQ hardware is characterized by a small number of qubits (50 to a few…

Hardware Architecture · Computer Science 2020-10-08 Siyuan Niu , Adrien Suau , Gabriel Staffelbach , Aida Todri-Sanial

This paper is motivated by two key observations. First, Toffoli ladders can be implemented in three distinct ways: with linear or polylogarithmic depth using no ancilla, or with logarithmic depth using ancilla qubits. Second, two…

Quantum Physics · Physics 2025-10-02 Maxime Remaud

As we venture into the Intermediate-Scale Quantum (ISQ) era, the proficiency of modular arithmetic operations becomes pivotal for advancing quantum cryptographic algorithms. This study presents an array of quantum circuits, each…

Quantum Physics · Physics 2023-11-16 Parfait Atchade-Adelomou , Saul Gonzalez

Implementing many important sub-circuits on near-term quantum devices remains a challenge due to the high levels of noise and the prohibitive depth on standard nearest-neighbour topologies. Overcoming these barriers will likely require…

Quantum Physics · Physics 2024-11-06 Angus Mingare , Anastasia Moroz , Marcell D Kovacs , Andrew G Green

The state of the art of quantum circuits using the ripple-carry strategy for the addition and comparison of two n-bit numbers is presented, as well as optimizations in the Clifford+T gate set, both in terms of CNOT-depth and T-depth, or…

Quantum Physics · Physics 2024-05-29 Maxime Remaud

We provide evidence that commonly held intuitions when designing quantum circuits can be misleading. In particular we show that: a) reducing the T-count can increase the total depth; b) it may be beneficial to trade CNOTs for measurements…

Quantum Physics · Physics 2021-01-14 Alexandru Paler , Oumarou Oumarou , Robert Basmadjian

When designing quantum circuits for a given unitary, it can be much cheaper to achieve a good approximation on most inputs than on all inputs. In this work we formalize this idea, and propose that such "optimistic quantum circuits" are…

Quantum computers are growing in size, and design decisions are being made now that attempt to squeeze more computation out of these machines. In this spirit, we design a method to boost the computational power of near-term quantum…

Quantum error detection (QED) offers a promising pathway to fault tolerance in near-term quantum devices by balancing error suppression with minimal resource overhead. However, its practical utility hinges on optimizing design…

Quantum Physics · Physics 2025-04-14 Tom Ginsberg , Vyom Patel

Quantum comparators and modular arithmetic are fundamental in many quantum algorithms. Current research mainly focuses on operations between two quantum states. However, various applications, such as integer factorization, optimization,…

Quantum Physics · Physics 2023-05-17 Yewei Yuan , Chao Wang , Bei Wang , Zhao-Yun Chen , Meng-Han Dou , Yu-Chun Wu , Guo-Ping Guo

We propose a memory-efficient finetuning algorithm for large language models (LLMs) that supports finetuning LLMs with 65B parameters in 2/3/4-bit precision on as little as one 24GB GPU. Our method, modular low-rank adaptation (ModuLoRA),…

Machine Learning · Computer Science 2024-03-12 Junjie Yin , Jiahao Dong , Yingheng Wang , Christopher De Sa , Volodymyr Kuleshov

We prove that quantum expander codes can be combined with quantum fault-tolerance techniques to achieve constant overhead: the ratio between the total number of physical qubits required for a quantum computation with faulty hardware and the…

Quantum Physics · Physics 2022-07-13 Omar Fawzi , Antoine Grospellier , Anthony Leverrier

Quantum computation is traditionally expressed in terms of quantum bits, or qubits. In this work, we instead consider three-level qu$trits$. Past work with qutrits has demonstrated only constant factor improvements, owing to the $\log_2(3)$…

As medium-scale quantum computers progress, the application of quantum algorithms across diverse fields like simulating physical systems, chemistry, optimization, and cryptography becomes more prevalent. However, these quantum computers,…

Quantum Physics · Physics 2024-04-04 Purnachandra Mandadapu

The imaginary-time evolution method is widely known to be efficient for obtaining the ground state in quantum many-body problems on a classical computer. A recently proposed quantum imaginary-time evolution method (QITE) faces problems of…

Quantum Physics · Physics 2021-06-04 Hirofumi Nishi , Taichi Kosugi , Yu-ichiro Matsushita

The section-carry based carry lookahead adder (SCBCLA) architecture was proposed as an efficient alternative to the conventional carry lookahead adder (CCLA) architecture for the physical implementation of computer arithmetic. In previous…

Hardware Architecture · Computer Science 2017-11-09 P Balasubramanian

Significant challenges remain with the development of macroscopic quantum computing, hardware problems of noise, decoherence, and scaling, software problems of error correction, and, most important, algorithm construction. Finding truly…

Quantum Physics · Physics 2022-12-05 James E. Steck , Nathan L. Thompson , Elizabeth C. Behrman

Reducing errors is essential for reliable quantum computation. Quantum error mitigation (QEM) and quantum error correction (QEC) are two leading approaches for this task, each with challenges: QEM suffers from high sampling costs and cannot…

Quantum Physics · Physics 2025-10-08 Sowmitra Das , Jinzhao Sun , Michael Hanks , Bálint Koczor , M. S. Kim