128,114 research outputs found
Introduction to Graphene Electronics -- A New Era of Digital Transistors and Devices
The speed of silicon-based transistors has reached an impasse in the recent
decade, primarily due to scaling techniques and the short-channel effect.
Conversely, graphene (a revolutionary new material possessing an atomic
thickness) has been shown to exhibit a promising value for electrical
conductivity. Graphene would thus appear to alleviate some of the drawbacks
associated with silicon-based transistors. It is for this reason why such a
material is considered one of the most prominent candidates to replace silicon
within nano-scale transistors. The major crux here, is that graphene is
intrinsically gapless, and yet, transistors require a band-gap pertaining to a
well-defined ON/OFF logical state. Therefore, exactly as to how one would
create this band-gap in graphene allotropes is an intensive area of growing
research. Existing methods include nano-ribbons, bilayer and multi-layer
structures, carbon nanotubes, as well as the usage of the graphene substrates.
Graphene transistors can generally be classified according to two working
principles. The first is that a single graphene layer, nanoribbon or carbon
nanotube can act as a transistor channel, with current being transported along
the horizontal axis. The second mechanism is regarded as tunneling, whether
this be band-to-band on a single graphene layer, or vertically between adjacent
graphene layers. The high-frequency graphene amplifier is another talking point
in recent research, since it does not require a clear ON/OFF state, as with
logical electronics. This paper reviews both the physical properties and
manufacturing methodologies of graphene, as well as graphene-based electronic
devices, transistors, and high-frequency amplifiers from past to present
studies. Finally, we provide possible perspectives with regards to future
developments.Comment: This is an updated version of our review article, due to be published
in Contemporary Physics (Sept 2013). Included are updated references, along
with a few minor corrections. (45 pages, 19 figures
Reason, causation and compatibility with the phenomena
'Reason, Causation and Compatibility with the Phenomena' strives to give answers to the philosophical problem of the interplay between realism, explanation and experience. This book is a compilation of essays that recollect significant conceptions of rival terms such as determinism and freedom, reason and appearance, power and knowledge. This title discusses the progress made in epistemology and natural philosophy, especially the steps that led from the ancient theory of atomism to the modern quantum theory, and from mathematization to analytic philosophy. Moreover, it provides possible gateways from modern deadlocks of theory either through approaches to consciousness or through historical critique of intellectual authorities.
This work will be of interest to those either researching or studying in colleges and universities, especially in the departments of philosophy, history of science, philosophy of science, philosophy of physics and quantum mechanics, history of ideas and culture. Greek and Latin Literature students and instructors may also find this book to be both a fascinating and valuable point of reference
Nature, Science, Bayes' Theorem, and the Whole of Reality
A fundamental problem in science is how to make logical inferences from
scientific data. Mere data does not suffice since additional information is
necessary to select a domain of models or hypotheses and thus determine the
likelihood of each model or hypothesis. Thomas Bayes' Theorem relates the data
and prior information to posterior probabilities associated with differing
models or hypotheses and thus is useful in identifying the roles played by the
known data and the assumed prior information when making inferences.
Scientists, philosophers, and theologians accumulate knowledge when analyzing
different aspects of reality and search for particular hypotheses or models to
fit their respective subject matters. Of course, a main goal is then to
integrate all kinds of knowledge into an all-encompassing worldview that would
describe the whole of reality
The Kantian Grounding of Einstein’s Worldview: (I) The Early Influence of Kant’s System of Perspectives
Recent perspectival interpretations of Kant suggest a way of relating his epistemology to empirical science that makes it plausible to regard Einstein’stheory of relativity as having a Kantian grounding. This first of two articles exploring this topic focuses on how the foregoing hypothesis accounts for variousresonances between Kant’s philosophy and Einstein’s science. The great attention young Einstein paid to Kant in his early intellectual development demonstrates the plausibility of this hypothesis, while certain features of Einstein’s cultural-political context account for his reluctance to acknowledge Kant’s influence, even though contemporary philosophers who regarded themselves as Kantians urged him to do so. The sequel argues that this Kantian grounding probably had a formative influence not only on Einstein’s discovery of the theory of relativity and his view of the nature of science, but also on his quasi-mystical, religious disposition
Probabilistic Knowledge as Objective Knowledge in Quantum Mechanics: Potential Powers Instead of Actual Properties
In classical physics, probabilistic or statistical knowledge has been always
related to ignorance or inaccurate subjective knowledge about an actual state
of affairs. This idea has been extended to quantum mechanics through a
completely incoherent interpretation of the Fermi-Dirac and Bose-Einstein
statistics in terms of "strange" quantum particles. This interpretation,
naturalized through a widespread "way of speaking" in the physics community,
contradicts Born's physical account of {\Psi} as a "probability wave" which
provides statistical information about outcomes that, in fact, cannot be
interpreted in terms of 'ignorance about an actual state of affairs'. In the
present paper we discuss how the metaphysics of actuality has played an
essential role in limiting the possibilities of understating things
differently. We propose instead a metaphysical scheme in terms of powers with
definite potentia which allows us to consider quantum probability in a new
light, namely, as providing objective knowledge about a potential state of
affairs.Comment: 35 pages, no figures. To be published in Probing the Meaning of
Quantum Mechanics, D. Aerts, C. de Ronde, H. Freytes and R. Giuntini (Eds.),
World Scientific, Singapore, forthcoming. More comments welcome
G\"odel Incompleteness and the Black Hole Information Paradox
Semiclassical reasoning suggests that the process by which an object
collapses into a black hole and then evaporates by emitting Hawking radiation
may destroy information, a problem often referred to as the black hole
information paradox. Further, there seems to be no unique prediction of where
the information about the collapsing body is localized. We propose that the
latter aspect of the paradox may be a manifestation of an inconsistent
self-reference in the semiclassical theory of black hole evolution. This
suggests the inadequacy of the semiclassical approach or, at worst, that
standard quantum mechanics and general relavity are fundamentally incompatible.
One option for the resolution for the paradox in the localization is to
identify the G\"odel-like incompleteness that corresponds to an imposition of
consistency, and introduce possibly new physics that supplies this
incompleteness. Another option is to modify the theory in such a way as to
prohibit self-reference. We discuss various possible scenarios to implement
these options, including eternally collapsing objects, black hole remnants,
black hole final states, and simple variants of semiclassical quantum gravity.Comment: 14 pages, 2 figures; revised according to journal requirement
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