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 problem have been proposed. Here we provide a detailed a review of the theory of decoherence-free subspaces and subsystems, focusing on their usefulness for pres...

As a novel approach with possible relevance to semiclassical gravity, we propose to define regions of space as quantum subsystems. After recalling how to divide a generic quantum system into “parts”, we apply this idea to a free scalar field in Minkowski space and we compare two different localization schemes. The first scheme is the standard one, induced by the local relativistic fields; the a...

in recent years, underactuated nonlinear dynamic systems trajectory tracking, such as space robots and manipulators with structural flexibility, has become a major field of interest due to the complexity and high computational load of these systems. hierarchical sliding mode control has been investigated recently for these systems; however, the instability phenomena will possibly occur, especia...

in this paper a double-shaft turbofan engine is considered to be in the design phase. therefore its environmental condition and critical source of failures has been studied and the subsystems and components has been identified. since it is in design phase, the project encounters to the lack of specified failure data. to overcome this problem, the generic data or expert judgments on the basis of...

We present and investigate a new class of quantum channels, what we call ‘universal collective rotation channels’, that includes the class of collective rotation channels as a special case. The fixed point set and noise commutant coincide for a channel in this class. Computing the precise structure of this C∗-algebra is a core problem in a particular noiseless subsystem method of quantum error ...

The algebraic structure underlying all the schemes for quantum information stabilization is argued to be fully contained in the reducibility of the operator algebra describing the interaction with the environment of the coding quantum system. This property amounts to the existence of a non-trivial group of symmetries for the global dynamics. We provide a unified framework which allows us to bui...

This paper is an expanded and more detailed version of the work [1] in which the Operator Quantum Error Correction formalism was introduced. This is a new scheme for the error correction of quantum operations that incorporates the known techniques — i.e. the standard error correction model, the method of decoherence-free subspaces, and the noiseless subsystem method — as special cases, and reli...