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Quantum gates executed on physical hardware are inevitably degraded by environmental noise. While state purification effectively distills static quantum resources, the dynamic execution of quantum algorithms requires a higher-order approach…

Quantum Physics · Physics 2026-04-02 Jiayi Zhao , Yu-Ao Chen , Guocheng Zhen , Chengkai Zhu , Ranyiliu Chen , Xin Wang

The Bloch Sphere visualization of the possible states of a single qubit has proved a useful pedagogical and conceptual tool as a one-to-one map between qubit states and points in a 3-D space. However, understanding many important concepts…

Quantum Physics · Physics 2024-05-31 Li-Heng Henry Chang , Shea Roccaforte , Ziyu Xu , Paul Cadden-Zimansky

This work provides a parametrization of the set of purifications of a 2x2 mixed state, and joint purifications (if any) of a given pair of mixed 2x2 states. The former is parametrized by SO(3, R), while the latter is parametrized by…

Quantum Physics · Physics 2007-05-23 Tiberiu Constantinescu , Viswanath Ramakrishna

Optimal Transport (OT) provides a useful geometric framework to estimate the permutation matrix under unsupervised cross-lingual word embedding (CLWE) models that pose the alignment task as a Wasserstein-Procrustes problem. However, linear…

Computation and Language · Computer Science 2022-12-06 Prince O Aboagye , Yan Zheng , Michael Yeh , Junpeng Wang , Zhongfang Zhuang , Huiyuan Chen , Liang Wang , Wei Zhang , Jeff Phillips

Fringe projection profilometry (FPP) is a widely used technique for measuring object surface form and three-dimensional (3D) geometry, capable of delivering high-precision, high-resolution measurements when paired with suitable cameras and…

Optics · Physics 2026-05-19 D. Weston , X. Kong , G. S. D. Gordon , S. Piano

It has been recently shown that there exist universal fundamental limits to the accuracy and efficiency of the transformation from noisy resource states to pure ones (e.g.,~distillation) in any well-behaved quantum resource theory…

Quantum Physics · Physics 2022-03-14 Kun Fang , Zi-Wen Liu

We revisit well-known protocols in quantum metrology using collective spins and propose a unifying picture for optimal state preparation based on a semiclassical description in phase space. We show how this framework allows for quantitative…

Quantum Physics · Physics 2023-05-04 Manuel H. Muñoz-Arias , Ivan H. Deutsch , Pablo M. Poggi

Quantum networks, which integrate multiple quantum computers and the channels connecting them, are crucial for distributed quantum information processing but remain inherently susceptible to channel noise. Channel purification emerges as a…

In this paper we have analysed in detail two different purification protocols. The first one, proposed by Sudarshan, is based on the preservation of probabilities.We have constructed a second protocol here based on optimisation of…

Quantum Physics · Physics 2007-05-23 Chirag Dhara , N. D. Hari Dass

Entanglement between distant quantum systems is a critical resource for implementing quantum communication. This property is affected by external agents and can be restored by employing efficient entanglement purification protocols. In this…

Quantum Physics · Physics 2024-09-05 Juan Mauricio Torres , József Zsolt Bernád , Rocío Gómez-Rosas

In this study, we investigate the problem of determining the maximum purity for absolutely separable and absolutely PPT quantum states. From the geometric viewpoint, this problem is equivalent to asking for the exact Euclidean radius of the…

Mathematical Physics · Physics 2025-10-23 Hoang Phi Dung , Vu The Khoi

This paper investigates the efficacy of quantum computing in two distinct machine learning tasks: feature selection for credit risk assessment and image classification for handwritten digit recognition. For the first task, we address the…

Quantum Physics · Physics 2025-11-05 JiaNing Long , Xuechen Liang

We investigate efficient entanglement purification through double selection process. This method works with higher noise thresholds for the communication channels and local operations, and achieves higher fidelity of purified states.…

Quantum Physics · Physics 2015-05-13 Keisuke Fujii , Katsuji Yamamoto

The geometric formulation of quantum mechanics is a very interesting field of research which has many applications in the emerging field of quantum computation and quantum information, such as schemes for optimal quantum computers. In this…

Quantum Physics · Physics 2014-04-24 Ole Andersson , Hoshang Heydari

We present a framework that formulates the quest for the most efficient quantum state tomography scheme as an optimization problem which can be solved numerically. This approach can be applied to a broad spectrum of relevant setups…

Quantum Physics · Physics 2021-12-17 Violeta N. Ivanova-Rohling , Guido Burkard , Niklas Rohling

It is known that mixed quantum states are highly entropic states of imperfect knowledge (i.e., incomplete information) about a quantum system, while pure quantum states are states of perfect knowledge (i.e., complete information) with…

Quantum Physics · Physics 2022-11-23 Carlo Cafaro , Paul M. Alsing

We consider qubit purification under simultaneous continuous measurement of the three non-commuting qubit operators \sigma_x, \sigma_y, \sigma_z. The purification dynamics is quantified by (i) the average purification rate, and (ii) the…

Quantum Physics · Physics 2012-10-24 Rusko Ruskov , Joshua Combes , Klaus Mølmer , Howard M. Wiseman

Uhlmann's fidelity function is one of the most widely used similarity measures in quantum theory. One definition of this function is that it is the minimum classical fidelity associated with a quantum-to-classical measurement procedure of…

Quantum Physics · Physics 2021-01-19 Sam Cree , Jamie Sikora

The Portfolio Optimization task has long been studied in the Financial Services literature as a procedure to identify the basket of assets that satisfy desired conditions on the expected return and the associated risk. A well-known approach…

We propose a model for data classification using isolated quantum $d$-level systems or else qudits. The procedure consists of an encoding phase where classical data are mapped on the surface of the qudit's Bloch hyper-sphere via rotation…

Quantum Physics · Physics 2023-07-27 A. Mandilara , B. Dellen , U. Jaekel , T. Valtinos , D. Syvridis