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We consider the sequential quantum channel discrimination problem using adaptive and non-adaptive strategies. In this setting the number of uses of the underlying quantum channel is not fixed but a random variable that is either bounded in…

Information Theory · Computer Science 2022-10-21 Yonglong Li , Christoph Hirche , Marco Tomamichel

Estimates of noise channels for quantum gates are required for most error mitigation techniques and are desirable for informing quantum error correction decoders. These estimates can be obtained by resource-intensive off-line…

Quantum Physics · Physics 2025-07-01 Lucas Daguerre , Mohan Sarovar

Randomness is both a useful way to model natural systems and a useful tool for engineered systems, e.g. in computation, communication and control. Fully random transformations require exponential time for either classical or quantum…

Quantum Physics · Physics 2016-05-04 Fernando G. S. L. Brandao , Aram W. Harrow , Michal Horodecki

The high computational cost of approaching the performance of Maximum-likelihood (ML) decoding has limited its practical use for decades. Because the complexity grows exponentially with the message length, researchers have spent years…

Signal Processing · Electrical Eng. & Systems 2026-04-21 Marwan Jalaleddine , Jiajie Li , Syed Mohsin Abbas , Warren J. Gross

Channel simulation is to simulate a noisy channel using noiseless channels with unlimited shared randomness. This can be interpreted as the reverse problem to Shannon's noisy coding theorem. In contrast to previous works, our approach…

Information Theory · Computer Science 2025-06-06 Shi-Bing Li , Ke Li , Lei Yu

The Linear Combination of Unitaries (LCU) method is a powerful scheme for the block encoding of operators but suffers from high overheads. In this work, we discuss the parallelisation of LCU and in particular the SELECT subroutine of LCU…

Quantum Physics · Physics 2024-08-22 Gregory Boyd

Recent demonstrations of superconducting quantum computers by Google and IBM and trapped-ion computers from IonQ fueled new research in quantum algorithms, compilation into quantum circuits, and empirical algorithmics. While online access…

Quantum Physics · Physics 2020-11-26 Aneeqa Fatima , Igor L. Markov

This paper is concerned with the problem of error-free communication over the i.i.d. duplication channel which acts on a transmitted sequence $ x_1 \cdots x_n $ by inserting a random number of copies of each symbol $ x_i $ next to the…

Information Theory · Computer Science 2020-08-13 Mladen Kovačević

In this paper, we proposed an experimental implementation of quantum random number generator(QRNG) with inherent randomness of quantum tunneling effect of electrons. We exploited InGaAs/InP diodes, whose valance band and conduction band…

Quantum Physics · Physics 2018-05-29 Haihan Zhou , Junlin Li , Dong Pan , Weixing Zhang , Guilu Long

In this work we design a specific simulation tool for quantum channels which is based on the use of a control system. This allows us to simulate an average quantum channel which is expressed in terms of an ensemble of channels, even when…

Quantum Physics · Physics 2018-12-19 Stefano Pirandola , Riccardo Laurenza , Leonardo Banchi

Using the recent ability of quantum computers to initialize quantum states rapidly with high fidelity, we use a function operating on a discrete set to create a simple class of quantum channels. Fixed points and periodic orbits, that are…

Quantum Physics · Physics 2023-08-25 A. C. Quillen , Nathan Skerrett

Decoded Quantum Interferometry (DQI) is a recently proposed quantum algorithm for approximating solutions to combinatorial optimization problems by reducing instances of linear satisfiability to bounded-distance decoding over superpositions…

We show that a quantum channel $\mathcal{N}$ constructed by averaging over $\mathcal{O}(\log d/\epsilon^2)$ randomly chosen unitaries gives a local $\epsilon$-randomizing map with non-negative probability. The idea comes from a small…

Quantum Physics · Physics 2010-02-19 Dong Pyo Chi , Kabgyun Jeong

We propose a general and systematic strategy to compile arbitrary quantum channels without using ancillary qubits, based on proximal policy optimization -- a powerful deep reinforcement learning algorithm. We rigorously prove that, in sharp…

Quantum Physics · Physics 2023-02-08 Weiyuan Gong , Si Jiang , Dong-Ling Deng

Quantum process tomography, the standard procedure to characterize any quantum channel in nature, is affected by a circular argument: in order to characterize the channel, the tomographic preparation and measurement need in turn to be…

Quantum Physics · Physics 2016-06-13 Michele Dall'Arno , Sarah Brandsen , Francesco Buscemi

We consider the problem of discriminating finite-dimensional quantum processes, also called quantum supermaps, that can consist of multiple time steps. Obtaining the ultimate performance for discriminating quantum processes is of…

Quantum Physics · Physics 2022-02-22 Kenji Nakahira , Kentaro Kato

Quantum memories are a crucial precondition in many protocols for processing quantum information. A fundamental problem that illustrates this statement is given by the task of channel discrimination, in which an unknown channel drawn from a…

Quantum Physics · Physics 2026-01-28 Ties-A. Ohst , Shijun Zhang , Hai Chau Nguyen , Martin Plávala , Marco Túlio Quintino

We consider transmitting a source across a pair of independent, non-ergodic channels with random states (e.g., slow fading channels) so as to minimize the average distortion. The general problem is unsolved. Hence, we focus on comparing two…

Information Theory · Computer Science 2009-09-29 J. Nicholas Laneman , Emin Martinian , Gregory W. Wornell , John G. Apostolopoulos

Permutation channels model communication and storage scenarios in which the positional identity of the physical carriers is partially or completely lost, so that the transmitted information is only accessible up to an unknown reordering.…

Quantum Physics · Physics 2026-05-29 Arnau Diebra , David González-Lociga , Mark Hillery , John Calsamiglia , Emili Bagan

In this work we improve the quantum communication rates of various quantum channels of interest using permutation-invariant quantum codes. We focus in particular on parametrized families of quantum channels and aim to improve bounds on…

Quantum Physics · Physics 2025-08-14 Sujeet Bhalerao , Felix Leditzky