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We construct a non-perturbative approach based on quantum averaging combined with resonant transformations to detect the resonances of a given Hamiltonian and to treat them. This approach, that generalizes the rotating-wave approximation,…

Quantum Physics · Physics 2007-05-23 M. Amniat-Talab , S. Guerin , H. R. Jauslin

We investigate the role of quantum monitoring in the dynamical manifestations of Hamiltonian quantum chaos. Specifically, we analyze the generalized spectral form factor, defined as the survival probability of a coherent Gibbs state under…

Quantum Physics · Physics 2026-02-04 Preethi Gopalakrishnan , András Grabarits , Adolfo del Campo

In this paper we propose a general method to quantify how "quantum" a set of quantum states is. The idea is to gauge the quantumness of the set by the worst-case difficulty of transmitting the states through a purely classical communication…

Quantum Physics · Physics 2007-05-23 Christopher A. Fuchs , Masahide Sasaki

Quantum trajectories are Markov chains modeling quantum systems subjected to repeated indirect measurements. Their stationary regime depends on what observables are measured on the probes used to indirectly measure the system. In this…

Mathematical Physics · Physics 2026-03-31 Tristan Benoist , Sascha Lill , Cornelia Vogel

A quantum trajectory describes the evolution of a quantum system undergoing indirect measurement. In the discrete-time setting, the state of the system is updated by applying Kraus operators according to the measurement results. From an…

Quantum Physics · Physics 2022-04-04 Maël Bompais , Nina H. Amini , Clément Pellegrini

Coupled quantum harmonic oscillators, studied by many authors using many different techniques over the decades, are frequently used toy-models to study open quantum systems. In this manuscript, we explicitly study the simplest oscillator…

Quantum Physics · Physics 2014-02-06 Yingkai Ouyang , Wee Hao Ng

Decoherence of a quantum system (which then starts to display classical features) results from the interaction of the system with the environment, and is well described in the framework of the theory of continuous quantum measurements…

Quantum Physics · Physics 2010-12-17 Michael B. Mensky

Recently, variational quantum metrology was proposed for Hamiltonians with multiplicative parameters, wherein the estimation precision can be optimized via variational circuits. However, systems with generic Hamiltonians still lack these…

Quantum Physics · Physics 2023-09-25 Le Bin Ho

An expression is derived characterizing the set of admissible rate pairs for simultaneous transmission of classical and quantum information over a given quantum channel, generalizing both the classical and quantum capacities of the channel.…

Quantum Physics · Physics 2007-05-23 I. Devetak , P. W. Shor

Simulating physical systems on quantum devices is one of the most promising applications of quantum technology. Current quantum approaches to simulating open quantum systems are still practically challenging on NISQ-era devices, because…

Quantum Physics · Physics 2024-09-09 Joseph Peetz , Scott E. Smart , Spyros Tserkis , Prineha Narang

We report experimental implementation of various types of qubit channels using an individual trapped ion. We analyzed experimental data and we performed tomographic reconstruction of quantum channels based on these data. Specifically, we…

Quantum Physics · Physics 2009-04-07 Thilo Hannemann , Christof Wunderlich , Martin Plesch , Mario Ziman , Vladimir Buzek

We investigate the capacity of bosonic quantum channels for the transmission of quantum information. Achievable rates are determined from measurable moments of the channel by showing that every channel can asymptotically simulate a Gaussian…

Quantum Physics · Physics 2009-11-13 Michael M. Wolf , David Perez-Garcia , Geza Giedke

A quantum communication channel can be put to many uses: it can transmit classical information, private classical information, or quantum information. It can be used alone, with shared entanglement, or together with other channels. For each…

Information Theory · Computer Science 2010-07-20 Graeme Smith

A measurement on a section K of the set of states of a finite dimensional C*-algebra is defined as an affine map from K to a probability simplex. Special cases of such sections are used in description of quantum networks, in particular…

Quantum Physics · Physics 2021-11-08 Anna Jencova

Measuring the power spectral density of a stochastic process, such as a stochastic force or magnetic field, is a fundamental task in many sensing applications. Quantum noise is becoming a major limiting factor to such a task in future…

The accurate computational study of wavepacket nuclear dynamics is considered to be a classically intractable problem, particularly with increasing dimensions. Here we present two algorithms that, in conjunction with other methods developed…

Quantum Physics · Physics 2025-12-30 Debadrita Saha , Philip Richerme , Srinivasan S. Iyengar

We study a class of quantum channels describing a quantum system, split into the direct sum of an excited and a ground sector, undergoing a one-way transfer of population from the former to the latter; this construction, which provides a…

Quantum Physics · Physics 2023-05-31 Davide Lonigro , Dariusz Chruściński

Quantum channels, also called quantum operations, are linear, trace preserving and completely positive transformations in the space of quantum states. Such operations describe discrete time evolution of an open quantum system interacting…

Quantum Physics · Physics 2011-10-04 Wojciech Roga

Using the known possibility to associate the completely positive maps with density matrices and recent results on expressing the density matrices with sets of classical probability distributions of dichotomic random variables we construct…

Quantum Physics · Physics 2019-04-09 Ashot Avanesov , Vladimir I. Man'ko

Quantum sensors may provide extremely high sensitivity and precision to extract key information in a quantum or classical physical system. A fundamental question is whether a quantum sensor is capable of uniquely inferring unknown…

Quantum Physics · Physics 2022-01-19 Qi Yu , Yuanlong Wang , Daoyi Dong , Ian R. Petersen