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We extend the notion of quantum reading to the case where the information to be retrieved, which is encoded into a set of quantum channels, is of quantum nature. We use two qubit unitaries describing the system environment interaction, with…

Quantum Physics · Physics 2024-05-14 Samad Khabbazi-Oskouei , Stefano Mancini , Milajiguli Rexiti

The communication complexity of a quantum channel is the minimal amount of classical communication required for classically simulating the process of preparation, transmission through the channel, and subsequent measurement of a quantum…

Quantum Physics · Physics 2013-12-24 A. Montina , M. Pfaffhauser , S. Wolf

We consider the estimation of two-qubit interactions when initial states of both qubit can be locally controlled, while the final state of only one qubit can be measured. This amounts to realize a model of quantum channel communication with…

Quantum Physics · Physics 2020-10-06 Milajiguli Rexiti , Stefano Mancini

We develop generalized bounds for quantum single-parameter estimation problems for which the coupling to the parameter is described by intrinsic multi-system interactions. For a Hamiltonian with $k$-system parameter-sensitive terms, the…

Quantum Physics · Physics 2007-05-23 Sergio Boixo , Steven T. Flammia , Carlton M. Caves , JM Geremia

Using a quantum circuit model we derive the maximal ability to distinguish which of several candidate Hamiltonians describe an open quantum system. This theory, in particular, provides the maximum information retrievable from continuous…

Quantum Physics · Physics 2015-06-22 Klaus Molmer

We develop a theory of quadratic quantum measurements by a mesoscopic detector. It is shown that quadratic measurements should have non-trivial quantum information properties, providing, for instance, a simple way of entangling two…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Wenjin Mao , Dmitri V. Averin , Rusko Ruskov , Alexander N. Korotkov

Quantum superchannels are maps whose input and output are quantum channels. Rather than taking the domain to be the space of all linear maps we motivate and define superchannels on the operator system spanned by quantum channels. Extension…

Quantum Physics · Physics 2022-10-04 Pádraig Daly

Network tomography refers to the use of inference techniques for inferring internal network states from end-to-end probes. Quantum probes, implemented by sending blocks of $n$ coherent-state pulses augmented with continuous-variable (CV)…

Quantum Physics · Physics 2026-04-29 Yufei Zheng , Zihao Gong , Saikat Guha , Don Towsley

A continuously measured quantum system may be described by restricted path integrals (RPI) or equivalently by non-Hermitian Hamiltonians. The measured system is then considered as an open system, the influence of the environment being taken…

Quantum Physics · Physics 2007-05-23 Michael B. Mensky

We study the implementation of quantum channels with quantum computers while minimizing the experimental cost, measured in terms of the number of Controlled-NOT (C-NOT) gates required (single-qubit gates are free). We consider three…

Quantum Physics · Physics 2017-05-17 Raban Iten , Roger Colbeck , Matthias Christandl

Motivated by applications to covert quantum radar, we analyze a covert quantum sensing problem, in which a legitimate user aims at estimating an unknown parameter taking finitely many values by probing a quantum channel while remaining…

Information Theory · Computer Science 2020-08-05 Mehrdad Tahmasbi , Matthieu Bloch

In this paper, we consider the generalized measurement where one particular quantum signal is unambiguously extracted from a set of non-commutative quantum signals and the other signals are filtered out. Simple expressions for the maximum…

Quantum Physics · Physics 2009-11-10 Masahiro Takeoka , Masashi Ban , Masahide Sasaki

An approach is developed, combining the ideas of quantum statistical mechanics and multichannel theory of scattering, for treating statistical systems whose constituents can possess different bound states realized as compact clusters. The…

Statistical Mechanics · Physics 2015-06-25 V. I. Yukalov , E. P. Yukalova

Various constraints concerning control fields can be imposed in the realistic implementations of quantum control systems. One of the most important is the restriction on the frequency spectrum of acceptable control parameters. It is…

Quantum Physics · Physics 2014-02-28 Łukasz Pawela , Zbigniew Puchała

Quantum Gaussian channels are fundamental models for communication and information processing in continuous-variable quantum systems. This work addresses both foundational aspects and physical implementation pathways for these channels.…

Quantum Physics · Physics 2025-05-08 Repana Devendra , Tiju Cherian John , K. Sumesh

Communication over a random-parameter quantum channel when the decoder is required to reconstruct the parameter sequence is considered. We study scenarios that include either strictly-causal, causal, or non-causal channel side information…

Information Theory · Computer Science 2021-09-28 Uzi Pereg

Quantum communication relies on optical implementations of channels, memories and repeaters. In the absence of perfect devices, a minimum requirement on real-world devices is that they preserve quantum correlations, meaning that they have…

Quantum Physics · Physics 2010-12-01 Nathan Killoran , Hauke Häseler , Norbert Lütkenhaus

We investigate the possibility of dividing quantum channels into concatenations of other channels, thereby studying the semigroup structure of the set of completely-positive trace-preserving maps. We show the existence of 'indivisible'…

Mathematical Physics · Physics 2015-06-26 Michael M. Wolf , J. Ignacio Cirac

A measurement model is a framework that describes a quantum measurement process. In this article we restrict attention to $MM$s on finite-dimensional Hilbert spaces. Suppose we want to measure an observable $A$ whose outcomes $A_x$ are…

Quantum Physics · Physics 2020-09-29 Stan Gudder

In this work we aim at quantifying quantum channel output similarity. In order to achieve this, we introduce the notion of quantum channel superfidelity, which gives us an upper bound on the quantum channel fidelity. This quantity is…

Quantum Physics · Physics 2018-10-12 Łukasz Pawela , Zbigniew Puchała