8,577 research outputs found
Sliding mode control of quantum systems
This paper proposes a new robust control method for quantum systems with
uncertainties involving sliding mode control (SMC). Sliding mode control is a
widely used approach in classical control theory and industrial applications.
We show that SMC is also a useful method for robust control of quantum systems.
In this paper, we define two specific classes of sliding modes (i.e.,
eigenstates and state subspaces) and propose two novel methods combining
unitary control and periodic projective measurements for the design of quantum
sliding mode control systems. Two examples including a two-level system and a
three-level system are presented to demonstrate the proposed SMC method. One of
main features of the proposed method is that the designed control laws can
guarantee desired control performance in the presence of uncertainties in the
system Hamiltonian. This sliding mode control approach provides a useful
control theoretic tool for robust quantum information processing with
uncertainties.Comment: 18 pages, 4 figure
Sampled-data design for robust control of a single qubit
This paper presents a sampled-data approach for the robust control of a
single qubit (quantum bit). The required robustness is defined using a sliding
mode domain and the control law is designed offline and then utilized online
with a single qubit having bounded uncertainties. Two classes of uncertainties
are considered involving the system Hamiltonian and the coupling strength of
the system-environment interaction. Four cases are analyzed in detail including
without decoherence, with amplitude damping decoherence, phase damping
decoherence and depolarizing decoherence. Sampling periods are specifically
designed for these cases to guarantee the required robustness. Two sufficient
conditions are presented for guiding the design of unitary control for the
cases without decoherence and with amplitude damping decoherence. The proposed
approach has potential applications in quantum error-correction and in
constructing robust quantum gates.Comment: 33 pages, 5 figures, minor correction
Information Surfaces in Systems Biology and Applications to Engineering Sustainable Agriculture
Systems biology of plants offers myriad opportunities and many challenges in
modeling. A number of technical challenges stem from paucity of computational
methods for discovery of the most fundamental properties of complex dynamical
systems. In systems engineering, eigen-mode analysis have proved to be a
powerful approach. Following this philosophy, we introduce a new theory that
has the benefits of eigen-mode analysis, while it allows investigation of
complex dynamics prior to estimation of optimal scales and resolutions.
Information Surfaces organizes the many intricate relationships among
"eigen-modes" of gene networks at multiple scales and via an adaptable
multi-resolution analytic approach that permits discovery of the appropriate
scale and resolution for discovery of functions of genes in the model plant
Arabidopsis. Applications are many, and some pertain developments of crops that
sustainable agriculture requires.Comment: 24 Pages, DoCEIS 1
Fault Tolerant Filtering and Fault Detection for Quantum Systems Driven By Fields in Single Photon States
The purpose of this paper is to solve a fault tolerant filtering and fault
detection problem for a class of open quantum systems driven by a
continuous-mode bosonic input field in single photon states when the systems
are subject to stochastic faults. Optimal estimates of both the system
observables and the fault process are simultaneously calculated and
characterized by a set of coupled recursive quantum stochastic differential
equations.Comment: arXiv admin note: text overlap with arXiv:1504.0678
Fabrication and properties of gallium phosphide variable colour displays
The unique properties of single-junction gallium phosphide devices incorporating both red and green radiative recombination centers were investigated in application to the fabrication of monolithic 5 x 7 displays capable of displaying symbolic and alphanumeric information in a multicolor format. A number of potentially suitable material preparation techniques were evaluated in terms of both material properties and device performance. Optimum results were obtained for double liquid-phase-epitaxial process in which an open-tube dipping technique was used for n-layer growth and a sealed tipping procedure for subsequent p-layer growth. It was demonstrated that to prepare devices exhibiting a satisfactory range of dominant wavelengths which can be perceived as distinct emission colors extending from the red through green region of the visible spectrum involves a compromise between the material properties necessary for efficient red emission and those considered optimum for efficient green emission
SciTech News Volume 71, No. 3 (2017)
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