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Quantum Fourier transform (QFT) is a key ingredient of many quantum algorithms where a considerable amount of ancilla qubits and gates are often needed to form a Hilbert space large enough for high-precision results. Qubit recycling reduces…

We explore the superstring theory on AdS_3 x S^3 x T^4 in the framework given in hep-th/9806194. We argue on the Hilbert space of "space-time CFT", and especially construct a suitable vacuum of this CFT from the physical degrees of freedom…

High Energy Physics - Theory · Physics 2010-02-03 K. Hosomichi , Y. Sugawara

Given a time series vector, how can we efficiently compute a specified part of Fourier coefficients? Fast Fourier transform (FFT) is a widely used algorithm that computes the discrete Fourier transform in many machine learning applications.…

Machine Learning · Computer Science 2020-08-31 Yong-chan Park , Jun-Gi Jang , U Kang

The concept of Hilbert space fragmentation (HSF) has recently been put forward as a routine to break quantum ergodicity. Although HSF exists widely in models with dynamical constraints, it is still challenging to tune it. Here, we propose a…

Quantum Physics · Physics 2024-10-28 Li Zhang , Yongguan Ke , Ling Lin , Chaohong Lee

The problem of recovering a signal from its Fourier magnitude is of paramount importance in various fields of engineering and applied physics. Due to the absence of Fourier phase information, some form of additional information is required…

Information Theory · Computer Science 2016-05-25 Kishore Jaganathan , Yonina C. Eldar , Babak Hassibi

In the past decade, several multi-resolution representation theories for graph signals have been proposed. Bipartite filter-banks stand out as the most natural extension of time domain filter-banks, in part because perfect reconstruction,…

Signal Processing · Electrical Eng. & Systems 2020-10-27 Eduardo Pavez , Benjamin Girault , Antonio Ortega , Philip A. Chou

The Fast Fourier Transform (FFT) is one of the most widely used algorithms in high performance computing, with critical applications in spectral analysis for both signal processing and the numerical solution of partial differential…

Numerical Analysis · Mathematics 2025-05-01 Laslo Hunhold , John Gustafson

Many phenomena are described by bivariate signals or bidimensional vectors in applications ranging from radar to EEG, optics and oceanography. The time-frequency analysis of bivariate signals is usually carried out by analyzing two separate…

Methodology · Statistics 2016-09-09 Julien Flamant , Nicolas Le Bihan , Pierre Chainais

We study nonuniform sampling in shift-invariant spaces and the construction of Gabor frames with respect to the class of totally positive functions whose Fourier transform factors as $ \hat g(\xi)= \prod_{j=1}^n (1+2\pi i\delta_j\xi)^{-1}…

Functional Analysis · Mathematics 2018-04-11 Karlheinz Gröchenig , José Luis Romero , Joachim Stöckler

Exploring the concept of the extended Galilei group G. Representations for field theories in a symplectic manifold have been derived in association with the method of the Wigner function. The representation is written in the light-cone of a…

High Energy Physics - Theory · Physics 2021-09-15 G. X. A. Petronilo , S. C. Ulhoa , K. V. S. Araújo , R. A. S. Paiva , R. G. G. Amorim , A. E. Santana

In this work, we present the \emph{twiddless fast Fourier transform (TFFT)}, a novel algorithm for computing the $N$-point discrete Fourier transform (DFT). The TFFT's divide strategy builds on recent results that decimate an $N$-point…

Computational Complexity · Computer Science 2025-12-23 Saulo Queiroz

Let $(g_{nm})_{n,m\in Z}$ be a Gabor frame for $L_2(R)$ for given window $g$. We show that the window $h^0=S^{-1/2} g$ that generates the canonically associated tight Gabor frame minimizes $\|g-h\|$ among all windows $h$ generating a…

Functional Analysis · Mathematics 2025-10-20 A. J. E. M Janssen , Thomas Strohmer

The synchrosqueezing transform (SST) has been developed as a powerful EMD-like tool for instantaneous frequency (IF) estimation and component separation of non-stationary multicomponent signals. Recently, a direct method of the…

Numerical Analysis · Mathematics 2020-10-22 Charles K. Chui , Qingtang Jiang , Lin Li , Jian Lu

A symplectic pseudospectral time-domain (SPSTD) scheme is developed to solve Schrodinger equation. Instead of spatial finite differences in conventional finite-difference time-domain (FDTD) method, the fast Fourier transform is used to…

Computational Physics · Physics 2018-05-09 Jing Shen , Wei E. I. Sha , Xiaojing Kuang , Jinhua Hu , Zhixiang Huang , Xianliang Wu

The graph Fourier transform (GFT) is a fundamental tool in graph signal processing and has recently been extended to the graph fractional Fourier transform (GFRFT). Existing sampling methods in the GFRFT domain are primarily designed to…

General Mathematics · Mathematics 2026-05-27 Yu Zhang , Jia-Yin Peng , Bing-Zhao Li

In this paper we study the nonuniform fast Fourier transform with nonequispaced spatial and frequency data (NNFFT) and the fast sinc transform as its application. The computation of NNFFT is mainly based on the nonuniform fast Fourier…

Numerical Analysis · Mathematics 2025-06-09 Melanie Kircheis , Daniel Potts , Manfred Tasche

This paper proposes a new loss using short-time Fourier transform (STFT) spectra for the aim of training a high-performance neural speech waveform model that predicts raw continuous speech waveform samples directly. Not only amplitude…

Audio and Speech Processing · Electrical Eng. & Systems 2018-10-31 Shinji Takaki , Toru Nakashika , Xin Wang , Junichi Yamagishi

Using the notions of frame transform and of square integrable projective representation of a locally compact group $G$, we introduce a class of isometries (tight frame transforms) from the space of Hilbert-Schmidt operators in the carrier…

Quantum Physics · Physics 2008-11-26 P. Aniello , V. I. Man'ko , G. Marmo

S-matrix is one of the fundamental observables of the quantum theory of relativistic particles. There have been attempts to understand the quantum dynamics of relativistic particles abstractly in terms of S-matrix bypassing a Lagrangian…

High Energy Physics - Theory · Physics 2022-11-29 Parthiv Haldar

In this paper, we discuss the development of a sublinear sparse Fourier algorithm for high-dimensional data. In ``Adaptive Sublinear Time Fourier Algorithm" by D. Lawlor, Y. Wang and A. Christlieb (2013), an efficient algorithm with…

Numerical Analysis · Mathematics 2019-07-02 Bosu Choi , Andrew Christlieb , Yang Wang