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Distinguishability is fundamental to information theory and extends naturally to quantum systems. While quantum state discrimination is well understood, quantum channel discrimination remains challenging due to the dynamic nature of…

Quantum Physics · Physics 2025-07-15 Kun Fang , Gilad Gour , Xin Wang

We investigate the tradeoff between the quality of an approximate version of a given measurement and the disturbance it induces in the measured quantum system. We prove that if the target measurement is a non-degenerate von Neumann…

Quantum Physics · Physics 2019-01-23 Anna-Lena K. Hashagen , Michael M. Wolf

This paper considers the distributed information bottleneck (D-IB) problem for a primitive Gaussian diamond channel with two relays and MIMO Rayleigh fading. The channel state is an independent and identically distributed (i.i.d.) process…

Information Theory · Computer Science 2023-05-09 Yi Song , Hao Xu , Kai-Kit Wong , Giuseppe Caire , Shlomo Shamai

We introduce a new framework for quantum channel discrimination in an adversarial setting, where the tester plays against an adversary. We show that in asymmetric hypothesis testing, the optimal type-II error exponent is precisely…

Quantum Physics · Physics 2026-01-01 Kun Fang , Hamza Fawzi , Omar Fawzi

Approximate degradability provides a powerful framework for bounding the quantum and private capacities of noisy quantum channels in regimes where exact degradability fails. While generic low-noise channels exhibit a non-degradability…

Information Theory · Computer Science 2026-02-02 Yun-Feng Lo , Yen-Chi Lee , Min-Hsiu Hsieh

In this work we study the problem of single-shot discrimination of von Neumann measurements, which we associate with measure-and-prepare channels. There are two possible approaches to this problem. The first one is simple and does not…

Quantum Physics · Physics 2018-11-08 Zbigniew Puchała , Łukasz Pawela , Aleksandra Krawiec , Ryszard Kukulski

We propose a quantum soft-covering problem for a given general quantum channel and one of its output states, which consists in finding the minimum rank of an input state needed to approximate the given channel output. We then prove a…

Quantum Physics · Physics 2024-09-25 Touheed Anwar Atif , S. Sandeep Pradhan , Andreas Winter

We present a quantum circuit that implements the random dilation superchannel, transforming parallel queries of an unknown quantum channel into the same number of parallel queries of a randomly chosen dilation isometry of the input channel.…

Quantum Physics · Physics 2026-05-19 Satoshi Yoshida , Ryotaro Niwa , Takeru Utsumi , Ryuji Takagi , Mio Murao

We consider the problem of performing linear regression over a stream of $d$-dimensional examples, and show that any algorithm that uses a subquadratic amount of memory exhibits a slower rate of convergence than can be achieved without…

Machine Learning · Computer Science 2020-10-13 Vatsal Sharan , Aaron Sidford , Gregory Valiant

We establish sharp non-asymptotic probabilistic bounds for the star discrepancy of double-infinite random matrices -- a canonical model for sequences of random point sets in high dimensions. By integrating the recently proved…

Statistics Theory · Mathematics 2026-01-09 Xiaoda Xu , Jun Xian

We prove a one-shot "minimax" converse bound for quantum channel coding assisted by positive partial transpose channels between sender and receiver. The bound is similar in spirit to the converse by Polyanskiy, Poor, and Verdu [IEEE Trans.…

Quantum Physics · Physics 2015-06-01 Joseph M. Renes

Log-concave sampling has witnessed remarkable algorithmic advances in recent years, but the corresponding problem of proving lower bounds for this task has remained elusive, with lower bounds previously known only in dimension one. In this…

Statistics Theory · Mathematics 2023-10-31 Sinho Chewi , Jaume de Dios Pont , Jerry Li , Chen Lu , Shyam Narayanan

Optimal dense coding using a partially-entangled pure state of Schmidt rank $\bar D$ and a noiseless quantum channel of dimension $D$ is studied both in the deterministic case where at most $L_d$ messages can be transmitted with perfect…

Quantum Physics · Physics 2007-05-23 Shengjun Wu , Scott M. Cohen , Yuqing Sun , Robert B. Griffiths

Storage and retrieval refer to the task of encoding an unknown quantum channel $\Lambda$ into a quantum state, known as the program state, such that the channel can later be retrieved. There are two strategies for this task: classical and…

Quantum Physics · Physics 2026-04-20 Satoshi Yoshida , Jisho Miyazaki , Mio Murao

The quantization of the output of a binary-input discrete memoryless channel to a smaller number of levels is considered. An algorithm which finds an optimal quantizer, in the sense of maximizing mutual information between the channel input…

Information Theory · Computer Science 2014-05-16 Brian M. Kurkoski , Hideki Yagi

Given the ability to apply an unknown quantum channel acting on a $d$-dimensional system, we develop a quantum algorithm for transforming its singular values. The spectrum of a quantum channel as a superoperator is naturally tied to its…

Quantum Physics · Physics 2025-07-16 Ryotaro Niwa , Zane Marius Rossi , Philip Taranto , Mio Murao

Real-world quantum systems interact with their environments, leading to the irreversible dynamics described by the Lindblad equation. Solutions to the Lindblad equation give rise to quantum channels $\Phi_t$ that characterize the evolution…

Quantum Physics · Physics 2025-03-07 L. Y. Visser , R. J. P. T. de Keijzer , O. Tse , S. J. J. M. F. Kokkelmans

We investigate the randomized and quantum communication complexity of the Hamming Distance problem, which is to determine if the Hamming distance between two n-bit strings is no less than a threshold d. We prove a quantum lower bound of…

Quantum Physics · Physics 2011-11-04 Wei Huang , Yaoyun Shi , Shengyu Zhang , Yufan Zhu

We study asymmetric binary channel discrimination, for qantum channels acting on separable Hilbert spaces. We establish quantum Stein's lemma for channels for both adaptive and parallel strategies, and show that under finiteness of the…

Quantum Physics · Physics 2023-08-25 Bjarne Bergh , Jan Kochanowski , Robert Salzmann , Nilanjana Datta

Channel Charting is a dimensionality reduction technique that learns to reconstruct a low-dimensional, physically interpretable map of the radio environment by taking advantage of similarity relationships found in high-dimensional channel…

Information Theory · Computer Science 2024-12-03 Florian Euchner , Phillip Stephan , Stephan ten Brink
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