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Quantum channels, which are completely positive and trace preserving mappings, can alter the dimension of a system; e.g., a quantum channel from a qubit to a qutrit. We study the convex set properties of dimension-altering quantum channels,…

Quantum Physics · Physics 2016-11-22 Dong-Sheng Wang

Every rotationless outer automorphism of a finite rank free group is represented by a particularly useful relative train track map called a CT. The main result of this paper is that the constructions of CTs can be made algorithmic. A key…

Group Theory · Mathematics 2017-06-07 Mark Feighn , Michael Handel

The quantum channel decomposition techniques, which contain the so-called probabilistic error cancellation and gate/wire cutting, are powerful approach for simulating a hard-to-implement (or an ideal) unitary operation by concurrently…

Quantum Physics · Physics 2023-08-30 Ryo Nagai , Shu Kanno , Yuki Sato , Naoki Yamamoto

We consider random perturbations of non-uniformly expanding maps, possibly having a non-degenerate critical set. We prove that, if the Lebesgue measure of the set of points failing the non-uniform expansion or the slow recurrence to the…

Dynamical Systems · Mathematics 2015-01-05 Xin Li , Helder Vilarinho

In this work, we propose a novel machine learning approach to compute the optimal transport map between two continuous distributions from their unpaired samples, based on the DeepParticle methods. The proposed method leads to a min-min…

Machine Learning · Statistics 2025-07-01 Yingyuan Li , Aokun Wang , Zhongjian Wang

We develop a primal-dual algorithm that allows for one-step inversion of spectral CT transmission photon counts data to a basis map decomposition. The algorithm allows for image constraints to be enforced on the basis maps during the…

Medical Physics · Physics 2016-05-04 Rina Foygel Barber , Emil Y. Sidky , Taly Gilat Schmidt , Xiaochuan Pan

Inevitably, assessing the overall performance of a quantum computer must rely on characterizing some of its elementary constituents and, from this information, formulate a broader statement concerning more complex constructions thereof.…

Quantum Physics · Physics 2019-08-14 Arnaud Carignan-Dugas , Matthew Alexander , Joseph Emerson

In the convex set of all $3\ot 3$ states with positive partial transposes, we show that one can take two extreme points whose convex combinations belong to the interior of the convex set. Their convex combinations may be even in the…

Quantum Physics · Physics 2014-12-12 Kil-Chan Ha , Seung-Hyeok Kye

Structural approximations to positive, but not completely positive maps are approximate physical realizations of these non-physical maps. They find applications in the design of direct entanglement detection methods. We show that many of…

Quantum Physics · Physics 2009-11-13 J. K. Korbicz , M. L. Almeida , J. Bae , M. Lewenstein , A. Acin

We determine the minimal experimental resources that ensure a unique solution in the estimation of trace-preserving quantum channels with both direct and convex optimization methods. A convenient parametrization of the constrained set is…

Quantum Physics · Physics 2011-06-13 M. Zorzi , F. Ticozzi , A. Ferrante

Optimal transport and its related problems, including optimal partial transport, have proven to be valuable tools in machine learning for computing meaningful distances between probability or positive measures. This success has led to a…

Machine Learning · Computer Science 2023-07-26 Xinran Liu , Yikun Bai , Huy Tran , Zhanqi Zhu , Matthew Thorpe , Soheil Kolouri

This paper discusses a more general contractive condition for a class of extended cyclic self-mappings on the union of a finite number of subsets of a metric space which are allowed to have a finite number of successive images in the same…

Functional Analysis · Mathematics 2012-08-06 M. De la Sen

This work builds a unified framework for the study of quadratic form distance measures as they are used in assessing the goodness of fit of models. Many important procedures have this structure, but the theory for these methods is dispersed…

Statistics Theory · Mathematics 2008-12-18 Bruce G. Lindsay , Marianthi Markatou , Surajit Ray , Ke Yang , Shu-Chuan Chen

We apply random matrix and free probability techniques to the study of linear maps of interest in quantum information theory. Random quantum channels have already been widely investigated with spectacular success. Here, we are interested in…

Quantum Physics · Physics 2019-02-27 Benoit Collins , Patrick Hayden , Ion Nechita

We characterize the completely positive trace-preserving maps on qutrits (qutrit channels) according to their covariance and symmetry properties. Both discrete and continuous groups are considered. It is shown how each symmetry group…

Quantum Physics · Physics 2011-07-20 Vahid Karimipour , Azam Mani , Laleh Memarzadeh

Physical transformations are described by linear maps that are completely positive and trace preserving (CPTP). However, maps that are positive (P) but not completely positive (CP) are instrumental to derive separability/entanglement…

Quantum Physics · Physics 2023-01-10 Maciej Lewenstein , Guillem Müller-Rigat , Jordi Tura , Anna Sanpera

Degradable quantum channels are an important class of completely positive trace-preserving maps. Among other properties, they offer a single-letter formula for the quantum and the private classical capacity and are characterized by the fact…

Quantum Physics · Physics 2017-11-23 David Sutter , Volkher B. Scholz , Andreas Winter , Renato Renner

We study quantum process tomography given the prior information that the map is a unitary or close to a unitary process. We show that a unitary map on a $d$-level system is completely characterized by a minimal set of $d^2{+}d$ elements…

Quantum Physics · Physics 2014-07-23 Charles H. Baldwin , Amir Kalev , Ivan H. Deutsch

This paper examines a stochastic deconvolution problem on compact symmetric spaces which is referred to as decompounding. This involves estimating the step distributions of a random walk, where in addition the number of steps between…

Statistics Theory · Mathematics 2026-04-20 Erik Kennerland

In graph analysis, a classic task consists in computing similarity measures between (groups of) nodes. In latent space random graphs, nodes are associated to unknown latent variables. One may then seek to compute distances directly in the…

Machine Learning · Statistics 2022-01-12 Nicolas Keriven