1,072 research outputs found
Binary Atomic Silicon Logic
It has long been anticipated that the ultimate in miniature circuitry will be
crafted of single atoms. Despite many advances made in scanned probe microscopy
studies of molecules and atoms on surfaces, challenges with patterning and
limited thermal stability have remained. Here we make progress toward those
challenges and demonstrate rudimentary circuit elements through the patterning
of dangling bonds on a hydrogen terminated silicon surface. Dangling bonds
sequester electrons both spatially and energetically in the bulk band gap,
circumventing short circuiting by the substrate. We deploy paired dangling
bonds occupied by one movable electron to form a binary electronic building
block. Inspired by earlier quantum dot-based approaches, binary information is
encoded in the electron position allowing demonstration of a binary wire and an
OR gate
Strictly periodic points and periodic factors of cellular automata
We show that the set of strictly temporally periodic points of cellular
automata with almost equicontinuous points is dense in the topological support
of the measure. This extends a result of Lena, Margara and Dennunzio about the
density of the set of strictly temporally periodic of cellular automata with
equicontinuous points.Comment: arXiv admin note: substantial text overlap with arXiv:1904.12302,
arXiv:1806.1021
Additive Cellular Automata Over Finite Abelian Groups: Topological and Measure Theoretic Properties
We study the dynamical behavior of D-dimensional (D >= 1) additive cellular automata where the alphabet is any finite abelian group. This class of discrete time dynamical systems is a generalization of the systems extensively studied by many authors among which one may list [Masanobu Ito et al., 1983; Giovanni Manzini and Luciano Margara, 1999; Giovanni Manzini and Luciano Margara, 1999; Jarkko Kari, 2000; Gianpiero Cattaneo et al., 2000; Gianpiero Cattaneo et al., 2004]. Our main contribution is the proof that topologically transitive additive cellular automata are ergodic. This result represents a solid bridge between the world of measure theory and that of topology theory and greatly extends previous results obtained in [Gianpiero Cattaneo et al., 2000; Giovanni Manzini and Luciano Margara, 1999] for linear CA over Z_m i.e. additive CA in which the alphabet is the cyclic group Z_m and the local rules are linear combinations with coefficients in Z_m. In our scenario, the alphabet is any finite abelian group and the global rule is any additive map. This class of CA strictly contains the class of linear CA over Z_m^n, i.e.with the local rule defined by n x n matrices with elements in Z_m which, in turn, strictly contains the class of linear CA over Z_m. In order to further emphasize that finite abelian groups are more expressive than Z_m we prove that, contrary to what happens in Z_m, there exist additive CA over suitable finite abelian groups which are roots (with arbitrarily large indices) of the shift map.
As a consequence of our results, we have that, for additive CA, ergodic mixing, weak ergodic mixing, ergodicity, topological mixing, weak topological mixing, topological total transitivity and topological transitivity are all equivalent properties. As a corollary, we have that invertible transitive additive CA are isomorphic to Bernoulli shifts. Finally, we provide a first characterization of strong transitivity for additive CA which we suspect it might be true also for the general case
Prototype worlds of video games
In this paper the author analyzes the phenomenon of prototype worlds – synthetic environments of simulators, video games and other types of software – used to conduct experiments at the level of user sensorium, environmental physics and social design. The author presents the evolution of the concept, beginning with Buckminister Fuller’s World Game project, moving through media experiments in the field of game design, and finally presenting contemporary applications (such as a drone pilot training project for the U.S. Air Force) and their implications.In this paper the author analyzes the phenomenon of prototype worlds – synthetic environments of simulators, video games and other types of software – used to conduct experiments at the level of user sensorium, environmental physics and social design. The author presents the evolution of the concept, beginning with Buckminister Fuller’s World Game project, moving through media experiments in the field of game design, and finally presenting contemporary applications (such as a drone pilot training project for the U.S. Air Force) and their implications
Self-Healing Cellular Automata to Correct Soft Errors in Defective Embedded Program Memories
Static Random Access Memory (SRAM) cells in ultra-low power Integrated Circuits (ICs) based on nanoscale Complementary Metal Oxide Semiconductor (CMOS) devices are likely to be the most vulnerable to large-scale soft errors. Conventional error correction circuits may not be able to handle the distributed nature of such errors and are susceptible to soft errors themselves. In this thesis, a distributed error correction circuit called Self-Healing Cellular Automata (SHCA) that can repair itself is presented. A possible way to deploy a SHCA in a system of SRAM-based embedded program memories (ePM) for one type of chip multi-processors is also discussed. The SHCA is compared with conventional error correction approaches and its strengths and limitations are analyzed
Modeling and manufacturability assessment of bistable quantum-dot cells
We have investigated the behavior of bistable cells made up of four quantum
dots and occupied by two electrons, in the presence of realistic confinement
potentials produced by depletion gates on top of a GaAs/AlGaAs heterostructure.
Such a cell represents the basic building block for logic architectures based
on the concept of Quantum Cellular Automata (QCA) and of ground state
computation, which have been proposed as an alternative to traditional
transistor-based logic circuits. We have focused on the robustness of the
operation of such cells with respect to asymmetries deriving from fabrication
tolerances. We have developed a 2-D model for the calculation of the electron
density in a driven cell in response to the polarization state of a driver
cell. Our method is based on the one-shot Configuration-Interaction technique,
adapted from molecular chemistry. From the results of our simulations, we
conclude that an implementation of QCA logic based on simple ``hole-arrays'' is
not feasible, because of the extreme sensitivity to fabrication tolerances. As
an alternative, we propose cells defined by multiple gates, where geometrical
asymmetries can be compensated for by adjusting the bias voltages. Even though
not immediately applicable to the implementation of logic gates and not
suitable for large scale integration, the proposed cell layout should allow an
experimental demonstration of a chain of QCA cells.Comment: 26 pages, Revtex, 13 figures, title and some figures changed and
minor revision
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