Decoherence in quantum systems and the network paradigm

“…Note that another type of introduction of decoherence was discussed in the paper of Mathis et al [20] where decoherence was established by reducing the density matrix under consideration of a factor of the tensor product describing the state space.…”

Section: Classical and Quantum Mechanical Transport Processesmentioning

confidence: 99%

Quantum transport, quantum effects and circuit functionality of nanostructured electronic circuits

Mathis

Felgenhauer

Fabel

2004

Circuit Theory & Apps

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“…A theory and a simulation algorithm for linear ion trap (Paul trap) quantum logic gates were presented . Decoherence was investigated from the circuit paradigm perspective . Classical equivalent circuit representation of Coulomb‐coupled arrays of quantum devices was presented .…”

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confidence: 99%

Guest Editorial – Special Issue on Quantum Circuits

Civalleri

Csurgay

Porod

2017

Circuit Theory & Apps

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The paper on 'Quantum Mechanical Computers' by Richard P. Feynman [1] was published in 1986. In the last 30 years, hope and disappointment alternated among engineers about design, fabrication, and operation of quantum computers. The report 'Quantum Shannon Theory' by Peter Shor [2] and his algorithm [3] envisaged progress quantum technology could achieve in metrology, communication, and computing. Visionary papers on 'The Second Quantum Revolution' [4] and on 'The Quantum Internet' [5] assumed that an industry of large-scale quantum machines might emerge.Engineers have been following the remarkable achievements the physics community demonstrated. Experimental platforms such as ion traps in vacuum, spin-based, quantum dot as well as quantum optics-based devices demonstrate the operation of quantum amplifiers and elementary quantum logic gates. However, large enough scale quantum machines could not be built. Challenges to meet the criteria necessary for a real engineering application turned to be daunting [6].In quantum circuits, components as well as their interconnected networks are 'open quantum systems'. There are circuits with components being open quantum systems; nevertheless, their interconnection can be described by classical models. Many nanoelectronic and molecular circuits belong to this class.Since 2001, the International Journal of Circuit Theory and Applications (IJCTA) has been paying attention to bridge circuit design as an engineering discipline with the physics of nanoscale and molecular systems, including the study of quantum phenomena in circuits. The potential of quantum parallelism was investigated [7]. It was shown that despite the qualitative difference in the function of classical and quantum circuits, some variants of the circuit paradigm remain applicable [8]. A theory and a simulation algorithm for linear ion trap (Paul trap) quantum logic gates were presented [9]. Decoherence was investigated from the circuit paradigm perspective [10]. Classical equivalent circuit representation of Coulomb-coupled arrays of quantum devices was presented [11]. State equations for two-level quantum systems in thermal environment [12] and equivalent circuits for quantum propagation of particles in crystals were investigated [13].This Special Issue on Quantum Circuits is devoted to the theory and applications of quantum circuits. The open quantum system character of devices as well as of circuits is assumed. The Special Issue intends to provide a forum for engineers to exchange their experience in their recent developments in the area of quantum circuits.The first macroscopic quantum effect was discoverd by Josephson already in the 1960s [14]. The first applications of circuit theory to assist the design of quantum circuits were applied for Josephson junction amplifiers and mixers [15,16]. In this Issue, the paper 'Quantum Theory of the Dissipative Josephson Parametric Amplifier' [17] deals with superconducting quantum circuits operating close to the quantum limit. Of special interest is the dynamic behav...

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