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This paper is concerned with the analysis of linear quantum optical networks. It provides a systematic approach to the construction a model for a given quantum network in terms of a system of quantum stochastic differential equations. This…

Quantum Physics · Physics 2014-03-26 Ian R. Petersen

We characterize the set of generalized quantum measurements that can be decomposed into a continuous measurement process using a stream of probe qubits and a tunable interaction Hamilto- nian. Each probe in the stream interacts weakly with…

Quantum Physics · Physics 2015-12-16 Jan Florjanczyk , Todd A. Brun

We consider realistic measurement systems, where measurements are accompanied by decoherence processes. The aim of this work is the construction of methods and algorithms for precise quantum measurements with fidelity close to the…

Quantum Physics · Physics 2017-01-10 Yu. I. Bogdanov , B. I. Bantysh , N. A. Bogdanova , A. B. Kvasnyy , V. F. Lukichev

The possibility of deforming the (associative or Lie) product to obtain alternative descriptions for a given classical or quantum system has been considered in many papers. Here we discuss the possibility of obtaining some novel alternative…

Quantum Physics · Physics 2008-11-26 E. Ercolessi , A. Ibort , G. Marmo , G. Morandi

We consider measurement-based quantum computation using the state of a spin-lattice system in equilibrium with a thermal bath and free to evolve under its own Hamiltonian. Any single qubit measurements disturb the system from equilibrium…

Quantum Physics · Physics 2009-09-23 David Jennings , Andrzej Dragan , Sean D. Barrett , Stephen D. Bartlett , Terry Rudolph

In the lectures we will be concerned with some aspects of physical implementations of quantum gate operations which are necessary for quantum information processing. We will discuss two possible realizations. One of them is based on qubits…

Quantum Physics · Physics 2007-05-23 Stefan Scheel , Jiannis Pachos , E. A. Hinds , Peter L. Knight

We consider quantum nonlinear systems with dissipation described within the Caldeira-Leggett model, i.e., by a nonlocal action in the path integral for the density matrix. Approximate classical-like formulas are derived in order to evaluate…

Statistical Mechanics · Physics 2007-05-23 A. Cuccoli , A. Fubini , A. Rossi , V. Tognetti , R. Vaia

Reference frames are of special importance in physics. They are usually considered to be idealized entities. However, in most situations, e.g. in laboratories, physical processes are described within reference frames constituted by physical…

Quantum Physics · Physics 2020-06-26 Jan Tuziemski

Decoherence is the phenomenon of non-unitary dynamics that arises as a consequence of coupling between a system and its environment. It has important harmful implications for quantum information processing, and various solutions to the…

Quantum Physics · Physics 2022-09-21 Daniel A. Lidar , K. Birgitta Whaley

Characterizing the nonclassicality of quantum systems under minimal assumptions is an important challenge for quantum foundations and technology. Here we introduce a theory-independent method of process tomography and perform it on a…

Quantum Physics · Physics 2026-03-18 Albert Aloy , Matteo Fadel , Thomas D. Galley , Caroline L. Jones , Markus P. Mueller

A quantum system subject to external fields is said to be controllable if these fields can be adjusted to guide the state vector to a desired destination in the state space of the system. Fundamental results on controllability are reviewed…

Nuclear Theory · Physics 2008-11-26 John W. Clark , Dennis G. Lucarelli , Tzyh-Jong Tarn

The main purpose of thispaper is to show that composite quantum-like (QL) systems can closely mimic the separable states of quantum systems, and that suitable physical systems exhibiting these states exist. It is shown that QL graphs can…

Quantum Physics · Physics 2026-03-24 Gregory D. Scholes

In this paper, we propose an efficient data-driven predictive control approach for general nonlinear processes based on a reduced-order Koopman operator. A Kalman-based sparse identification of nonlinear dynamics method is employed to…

Systems and Control · Electrical Eng. & Systems 2024-04-02 Xuewen Zhang , Minghao Han , Xunyuan Yin

We study decoherence in a simple quantum mechanical model using two approaches. Firstly, we follow the conventional approach to decoherence where one is interested in solving the reduced density matrix from the perturbative master equation.…

Quantum Physics · Physics 2015-05-20 Jurjen F. Koksma , Tomislav Prokopec , Michael G. Schmidt

Composite quantum systems can be decomposed into subsystems in many different inequivalent ways. We call a particular decomposition a meronomic reference frame for the system. We apply the ideas of quantum reference frames to characterize…

Quantum Physics · Physics 2019-07-12 Austin Hulse , Benjamin Schumacher

This paper presents a Koopman lifting linearization method that is applicable to nonlinear dynamical systems having both stable and unstable regions. It is known that DMD and other standard data-driven methods face a fundamental difficulty…

Machine Learning · Computer Science 2023-01-18 Jerry Ng , H. Harry Asada

Quantum computing employs controllable interactions to perform sequences of logical gates and entire algorithms on quantum registers. This paradigm has been widely explored, e.g., for simulating dynamics of manybody systems by decomposing…

Quantum Physics · Physics 2025-05-21 S. Alipour , A. T. Rezakhani , Alireza Tavanfar , K. Mölmer , T. Ala-Nissila

The simulation of complex quantum systems on a quantum computer is studied, taking the kicked Harper model as an example. This well-studied system has a rich variety of dynamical behavior depending on parameters, displays interesting…

Quantum Physics · Physics 2007-05-23 Benjamin Levi , Bertrand Georgeot

The descriptions of the quantum realm and the macroscopic classical world differ significantly not only in their mathematical formulations but also in their foundational concepts and philosophical consequences. When and how physical systems…

Quantum Physics · Physics 2008-12-02 Johannes Kofler

Quantum states inevitably decay with time into a probabilistic mixture of classical states, due to their interaction with the environment and measurement instrumentation. We present the first measurement of the decoherence dynamics of…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 H. Wang , M. Hofheinz , M. Ansmann , R. C. Bialczak , Erik Lucero , M. Neeley , A. D. O'Connell , D. Sank , M. Weides , J. Wenner , A. N. Cleland , John M. Martinis