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We provide a new quantum algorithm that efficiently determines the quality of a least-squares fit over an exponentially large data set by building upon an algorithm for solving systems of linear equations efficiently (Harrow et al., Phys.…

Quantum Physics · Physics 2013-01-10 Nathan Wiebe , Daniel Braun , Seth Lloyd

As quantum computing approaches the threshold where certain tasks demonstrably outpace their classical machines, the need for a precise, clear, consensus-driven definition of quantum advantage becomes essential. Rapid progress in the field…

Amplitude encoding of real-world data on quantum computers is often the workflow bottleneck: direct amplitude encoding scales poorly with input size and can offset any speedups in subsequent processing. Fourier-based sparse amplitude…

Quantum Physics · Physics 2026-03-26 Gekko Budiutama , Shunsuke Daimon , Xinchi Huang , Hirofumi Nishi , Yu-ichiro Matsushita

We analyze the performance of adiabatic quantum computation (AQC) under the effect of decoherence. To this end, we introduce an inherently open-systems approach, based on a recent generalization of the adiabatic approximation. In contrast…

Quantum Physics · Physics 2009-11-11 M. S. Sarandy , D. A. Lidar

We present a general methodology to obtain the basis of qudits which are admissible to Quantum Fourier Transform (QFT). We first study this method for qubits to characterize the ensemble that works for the Hadamard transformation (QFT for…

Quantum Physics · Physics 2012-08-28 Arpita Maitra , Santanu Sarkar

We have studied the decoherence properties of adiabatic quantum computation (AQC) in the presence of in general non-Markovian, e.g., low-frequency, noise. The developed description of the incoherent Landau-Zener transitions shows that the…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 M. H. S. Amin , Dmitri V. Averin , James A. Nesteroff

The errors that arise in a quantum channel can be corrected perfectly if and only if the channel does not decrease the coherent information of the input state. We show that, if the loss of coherent information is small, then approximate…

Quantum Physics · Physics 2007-05-23 Benjamin Schumacher , Michael D. Westmoreland

Very recently the most general ensemble of qubits are identified using the notion of linearity; any of these qubits gets accepted by a Hadamard gate to generate the equal superposition of the qubit and its orthogonal. Towards more…

Quantum Physics · Physics 2012-08-28 Arpita Maitra

Quantum mechanics requires the operation of quantum computers to be unitary, and thus makes it important to have general techniques for developing fast quantum algorithms for computing unitary transforms. A quantum routine for computing a…

Quantum Physics · Physics 2007-05-23 Peter Hoyer

Quantization-aware training (QAT) schemes have been shown to achieve near-full precision accuracy. They accomplish this by training a quantized model for multiple epochs. This is computationally expensive, mainly because of the full…

Machine Learning · Computer Science 2024-11-19 Saleh Ashkboos , Bram Verhoef , Torsten Hoefler , Evangelos Eleftheriou , Martino Dazzi

Due to the great difficulty in scalability, quantum computers are limited in the number of qubits during the early stages of the quantum computing regime. In addition to the required qubits for storing the corresponding eigenvector, suppose…

Quantum Physics · Physics 2013-11-15 Chen-Fu Chiang

Using the methods of quantum trajectories we investigate the effects of dissipative decoherence in a quantum computer algorithm simulating dynamics in various regimes of quantum chaos including dynamical localization, quantum ergodic regime…

Quantum Physics · Physics 2016-09-08 Jae Weon Lee , Dima L. Shepelyansky

We define formally decohered quantum computers (using density matrices), and present a simulation of them by a probabalistic classical Turing Machine. We study the slowdown of the simulation for two cases: (1) sequential quantum computers,…

Quantum Physics · Physics 2007-05-23 Dorit Aharonov , Michael Ben-Or

This paper shows that it is possible to improve the computational cost, the memory requirements and the accuracy of Quick Fourier Transform (QFT) algorithm for power-of-two FFT (Fast Fourier Transform) just introducing a slight modification…

Data Structures and Algorithms · Computer Science 2013-01-07 Lorenzo Pasquini

Quantum computing's potential for exponential speedup is fundamentally limited by decoherence, a phenomenon arising from environmental interactions. Non-Hermitian quantum mechanics, particularly $PT$-symmetric systems, offers a novel…

Quantum Physics · Physics 2025-11-25 Duttatreya , Ipsika Mohanty , Sanjib Dey

We investigate the ability of transformer models to approximate the CKY algorithm, using them to directly predict a sentence's parse and thus avoid the CKY algorithm's cubic dependence on sentence length. We find that on standard…

Computation and Language · Computer Science 2023-11-07 Ghazal Khalighinejad , Ollie Liu , Sam Wiseman

We present a Fourier neural network (FNN) that can be mapped directly to the Fourier decomposition. The choice of activation and loss function yields results that replicate a Fourier series expansion closely while preserving a…

Machine Learning · Computer Science 2021-04-30 Marieme Ngom , Oana Marin

The scalability of quantum computing is currently limited by physical, technological, and architectural constraints that hinder the integration of a large number of qubits within a single quantum processor. Distributed quantum computing…

Quantum Physics · Physics 2026-05-12 F. Javier Cardama , Jorge Vázquez-Pérez , Tomás F. Pena , Andrés Gómez

We introduce a quantum algorithm to perform the Laplace transform on quantum computers. Already, the quantum Fourier transform (QFT) is the cornerstone of many quantum algorithms, but the Laplace transform or its discrete version has not…

We study the complexity of Decoded Quantum Interferometry (DQI), a quantum algorithm for approximate optimization. First, we show that the algorithm resists classical simulation strategies based on locating outputs with large probabilities.…

Quantum Physics · Physics 2026-05-01 Kunal Marwaha , Bill Fefferman , Alexandru Gheorghiu , Vojtech Havlicek