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Related papers: Randomized gap and amplitude estimation

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This paper is concerned with the phase estimation algorithm in quantum computing algorithms, especially the scenarios where (1) the input vector is not an eigenvector; (2) the unitary operator is not exactly implemented; (3) random…

Quantum Physics · Physics 2022-08-10 Xiantao Li

We develop several algorithms for performing quantum phase estimation based on basic measurements and classical post-processing. We present a pedagogical review of quantum phase estimation and simulate the algorithm to numerically determine…

Quantum Physics · Physics 2013-07-30 Krysta M. Svore , Matthew B. Hastings , Michael Freedman

The spectral gap occupies a role of central importance in many open problems in physics. We present an approach for evaluating the spectral gap of a Hamiltonian from a simple ratio of two expectation values, both of which are evaluated…

Quantum Physics · Physics 2026-01-26 Jacob M. Leamer , Alicia B. Magann , Gerard McCaul , Denys I. Bondar

We consider a class of random quantum circuits where at each step a gate from a universal set is applied to a random pair of qubits, and determine how quickly averages of arbitrary finite-degree polynomials in the matrix elements of the…

Quantum Physics · Physics 2015-05-14 Winton G. Brown , Lorenza Viola

Phase estimation is used in many quantum algorithms, particularly in order to estimate energy eigenvalues for quantum systems. When using a single qubit as the probe (used to control the unitary we wish to estimate the eigenvalue of), it is…

Quantum Physics · Physics 2023-03-23 Peyman Najafi , Pedro C. S. Costa , Dominic W. Berry

Random unitary matrices find a number of applications in quantum information science, and are central to the recently defined boson sampling algorithm for photons in linear optics. We describe an operationally simple method to directly…

Quantum Physics · Physics 2017-03-08 Nicholas J. Russell , Levon Chakhmakhchyan , Jeremy L. O'Brien , Anthony Laing

We present a physical scheme for implementing quantum phase estimation via weakly coupled double quantum-dot molecules embedded in a microcavity. During the same process of implementation, we can also realize the calibration of a timepiece…

Quantum Physics · Physics 2015-05-13 Ping Dong , Zhuo-Liang Cao

Quantum phase estimation plays a central role in quantum simulation as it enables the study of spectral properties of many-body quantum systems. Most variants of the phase estimation algorithm require the application of the global unitary…

Random quantum circuits are a central concept in quantum information theory with applications ranging from demonstrations of quantum computational advantage to descriptions of scrambling in strongly-interacting systems and black holes. The…

Quantum Physics · Physics 2021-08-23 Jonas Haferkamp , Nicholas Hunter-Jones

A method for estimating the spectral gap along with higher eigenvalues of nonequilateral quantum graphs has been introduced by Amini and Cohen-Steiner recently: it is based on a new transference principle between discrete and continuous…

Functional Analysis · Mathematics 2020-12-11 Delio Mugnolo , Marvin Plümer

We consider a random quantum channel obtained by taking a selection of $d$ independent and Haar distributed $N$ dimensional unitaries. We follow the argument of Hastings to bound the spectral gap in terms of eigenvalues and adapt it to give…

Probability · Mathematics 2025-04-15 Sarah Timhadjelt

We discuss the implementation of an iterative quantum phase estimation algorithm, with a single ancillary qubit. We suggest using this algorithm as a benchmark for multi-qubit implementations. Furthermore we describe in detail the smallest…

Quantum Physics · Physics 2010-03-26 M. Dobsicek , G. Johansson , V. S. Shumeiko , G. Wendin

How to achieve an arbitrary real-valued probability amplitude in the general single-partite or multipartite quantum system without measuring any other quantum state's probability amplitude? How to achieve an arbitrary real-valued…

Quantum Physics · Physics 2020-09-01 Xu Guanlei

In quantum computation, amplitude estimation is a fundamental subroutine that is utilized in various quantum algorithms. A general important task of such estimation problems is to characterize the estimation lower bound, which is referred…

Quantum Physics · Physics 2025-07-10 Kohei Oshio , Yohichi Suzuki , Kaito Wada , Keigo Hisanaga , Shumpei Uno , Naoki Yamamoto

Qubit noise spectroscopy is an important tool for the experimental investigation of open quantum systems. However, conventional techniques for noise spectroscopy are time-consuming, because they require measurements of the noise spectral…

Quantum Physics · Physics 2025-06-24 Kaixin Huang , Demitry Farfurnik , Alireza Seif , Mohammad Hafezi , Yi-Kai Liu

Many quantum algorithms contain an important subroutine, the quantum amplitude estimation. As the name implies, this is essentially the parameter estimation problem and thus can be handled via the established statistical estimation theory.…

Quantum Physics · Physics 2022-01-10 Tomoki Tanaka , Shumpei Uno , Tamiya Onodera , Naoki Yamamoto , Yohichi Suzuki

Quantum advantage requires overcoming noise-induced degradation of quantum systems. Conventional methods for reducing noise such as error mitigation face scalability issues in deep circuits. Specifically, noise hampers the extraction of…

Quantum Physics · Physics 2023-12-05 Yonglong Ding , Ruyu Yang

Amplitude estimation is a fundamental quantum algorithmic primitive that enables quantum computers to achieve quadratic speedups for a large class of statistical estimation problems, including Monte Carlo methods. The main drawback from the…

Iterative phase estimation has long been used in quantum computing to estimate Hamiltonian eigenvalues. This is done by applying many repetitions of the same fundamental simulation circuit to an initial state, and using statistical…

Quantum Physics · Physics 2019-07-25 Ian D. Kivlichan , Christopher E. Granade , Nathan Wiebe

A large number of problems in science can be solved by preparing a specific eigenstate of some Hamiltonian H. The generic cost of quantum algorithms for these problems is determined by the inverse spectral gap of H for that eigenstate and…

Quantum Physics · Physics 2013-04-23 Rolando D. Somma , Sergio Boixo