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The logarithm-determinant is an widely-present operation in many areas of physics and computer science. Derivatives of the logarithm-determinant compute physically relevant quantities in statistical physics models, quantum field theories,…

Quantum Physics · Physics 2025-09-23 Thomas E. Baker , Jaimie A. Greasley

The success of quantum information processing applications relies on accurate and efficient characterization of quantum states, especially nearly-pure states. In this work, we investigate a procedure for adaptive qubit state tomography…

Quantum Physics · Physics 2018-09-05 Aonan Zhang , Yujie Zhang , Feixiang Xu , Long Li , Lijian Zhang

We show a simple generalization of the quantum walk algorithm for search in backtracking trees by Montanaro (ToC 2018) to the case where vertices can have different times of computation. If a vertex $v$ in the tree of depth $D$ is computed…

Quantum Physics · Physics 2025-11-25 Jevgēnijs Vihrovs

Squared Wasserstein distance is a frequently used tool to measure discrepancy between probability distributions. This distance is typically computed between empirical measures of size $n$ from two underlying random samples. Unfortunately,…

Machine Learning · Statistics 2026-05-20 Peter Matthew Jacobs , Jeff M. Phillips

Finance is one of the promising field for industrial application of quantum computing. In particular, quantum algorithms for calculation of risk measures such as the value at risk and the conditional value at risk of a credit portfolio have…

Quantum Physics · Physics 2022-01-28 Koichi Miyamoto

We consider performing phase estimation under the following conditions: we are given only one copy of the input state, the input state does not have to be an eigenstate of the unitary, and the state must not be measured. Most quantum…

Quantum Physics · Physics 2022-12-13 Patrick Rall

The problem of discriminating with minimum error between two mixed quantum states is reviewed, with emphasize on the detection operators necessary for performing the measurement. An analytical result is derived for the minimum probability…

Quantum Physics · Physics 2009-11-10 Ulrike Herzog

The von Neumann and quantum R\'enyi entropies characterize fundamental properties of quantum systems and lead to theoretical and practical applications in many fields. Quantum algorithms for estimating quantum entropies, using a quantum…

Quantum Physics · Physics 2023-10-13 Youle Wang , Benchi Zhao , Xin Wang

In recent years, several measures have been proposed for characterizing the coherence of a given quantum state. We derive several results that illuminate how these measures behave when restricted to pure states. Notably, we present an…

Quantum Physics · Physics 2016-10-26 Jianxin Chen , Shane Grogan , Nathaniel Johnston , Chi-Kwong Li , Sarah Plosker

It is a central fact in quantum mechanics that non-orthogonal states cannot be distinguished perfectly. This property ensures the security of quantum key distribution. It is therefore an important task in quantum communication to design and…

Quantum Physics · Physics 2023-11-27 Lorcan O. Conlon , Falk Eilenberger , Ping Koy Lam , Syed M. Assad

Pattern recognition algorithms are commonly employed to simplify the challenging and necessary step of track reconstruction in sub-atomic physics experiments. Aiding in the discrimination of relevant interactions, pattern recognition seeks…

Quantum Physics · Physics 2021-07-14 Gregory Quiroz , Lauren Ice , Andrea Delgado , Travis S. Humble

Matrix scaling is a simple to state, yet widely applicable linear-algebraic problem: the goal is to scale the rows and columns of a given non-negative matrix such that the rescaled matrix has prescribed row and column sums. Motivated by…

Quantum Physics · Physics 2021-10-01 Sander Gribling , Harold Nieuwboer

We study the quantitative characterization of the performance of qubit measurements in this paper. In particular, the back-action evading nature of quantum nondemolition (QND) readout of qubits is fully quantified by quantum trace distance.…

Quantum Physics · Physics 2022-08-16 He Wang , Ya Cao

Quantum Computing is a rapidly developing field with the potential to tackle the increasing computational challenges faced in high-energy physics. In this work, we explore the potential and limitations of variational quantum algorithms in…

Quantum relative entropy, a quantum generalization of the renowned Kullback-Leibler divergence, serves as a fundamental measure of the distinguishability between quantum states and plays a pivotal role in quantum information science.…

Quantum Physics · Physics 2025-10-02 Yuchen Lu , Kun Fang

The computational cost of preparing a quantum state can be substantial depending on the structure of data to be encoded. Many quantum algorithms require repeated sampling to find the answer, mandating reconstruction of the same input state…

In this paper we consider feedback control algorithms for the rapid purification of a bipartite state consisting of two qubits, when the observer has access to only one of the qubits. We show 1) that the algorithm that maximizes the average…

Quantum Physics · Physics 2009-11-13 Charles D. Hill , J. F. Ralph

A longstanding belief in quantum tomography is that estimating a mixed state is far harder than estimating a pure state. This is borne out in the mathematics, where mixed state algorithms have always required more sophisticated techniques…

Quantum Physics · Physics 2025-11-21 Angelos Pelecanos , Jack Spilecki , Ewin Tang , John Wright

Quantum algorithms for ground-state energy estimation of chemical systems require a high-quality initial state. However, initial state preparation is commonly either neglected entirely, or assumed to be solved by a simple product state like…

Quantum computers are a highly promising tool for efficiently simulating quantum many-body systems. The preparation of their eigenstates is of particular interest and can be addressed, e.g., by quantum phase estimation algorithms. The…

Quantum Physics · Physics 2025-08-28 Xiaoyu Liu , Benjamin F. Schiffer , Jordi Tura