240,177 research outputs found
Limits, applicability and generalizations of the Landauer's erasure principle
Almost sixty years since Landauer linked the erasure of information with an
increase of entropy, his famous erasure principle and byproducts like
reversible computing are still subjected to debates in the scientific
community. In this work we use the Liouville theorem to establish three
different types of the relation between manipulation of information by a
logical gate and the change of its physical entropy, corresponding to three
types of the final state of environment. A time-reversible relation can be
established when the final states of environment corresponding to different
logical inputs are macroscopically distinguishable, showing a path to
reversible computation and erasure of data with no entropy cost. A weak
relation, giving the entropy change of for an erasure gate, can be
deduced without any thermodynamical argument, only requiring the final states
of environment to be macroscopically indistinguishable. The common strong
relation that links entropy cost to heat requires the final states of
environment to be in a thermal equilibrium. We argue in this work that much of
the misunderstanding around the Landauer's erasure principle stems from not
properly distinguishing the limits and applicability of these three different
relations. Due to new technological advances, we emphasize the importance of
taking into account the time-reversible and weak types of relation to link the
information manipulation and entropy cost in erasure gates beyond the
considerations of environments in thermodynamic equilibrium.Comment: 26 pages, 3 figure
How the Quantum Universe Became Classical
This is an informal introduction to the ideas of decoherence and emergent
classicality, including a simple account of the decoherent histories approach
to quantum theory. It is aimed at undergraduates with a basic appreciation of
quantum theory. The emphasis is on simple physical ideas and pictures.Comment: 24 pages, 11 figure
Three Remarks on “Reflective Equilibrium“
John Rawls’ “reflective equilibrium” ranges amongst the most popular conceptions in contemporary ethics when it comes to the basic methodological question of how to justify and trade off different normative positions and attitudes. Even where Rawls’ specific contractualist account is not adhered to, “reflective equilibrium” is readily adopted as the guiding idea of coherentist approaches, seeking moral justification not in a purely deductive or inductive manner, but in some balancing procedure that will eventually procure a stable adjustment of relevant doctrines and standpoints. However, it appears that the widespread use of this idea has led to some considerable deviations from its meaning within Rawls’ original framework and to a critical loss of conceptual cogency as an ethico-hermeneutical tool. This contribution identifies three kinds of “balancing” constellations that are frequently, but inadequately brought forth under the heading of Rawlsian “reflective equilibrium”: balancing theoretical accounts against intuitive convictions; balancing general principles against particular judgements; balancing opposite ethical conceptions or divergent moral statements, respectively. It is argued that each of these applications departs from Rawls’ original construction of “reflective equilibrium” and also deprives the idea of its reliability in clarifying and weighing moral stances
Uncertainty relations and possible experience
The uncertainty principle can be understood as a condition of joint indeterminacy of classes of properties in quantum theory. The mathematical expressions most closely associated with this principle have been the uncertainty relations, various inequalities exemplified by the well known expression regarding position and momentum introduced by Heisenberg. Here, recent work involving a new sort of “logical” indeterminacy principle and associated relations introduced by Pitowsky, expressable directly in terms of probabilities of outcomes of measurements of sharp quantum observables, is reviewed and its quantum nature is discussed. These novel relations are derivable from Boolean “conditions of possible experience” of the quantum realm and have been considered both as fundamentally logical and as fundamentally geometrical. This work focuses on the relationship of indeterminacy to the propositions regarding the values of discrete, sharp observables of quantum systems. Here, reasons for favoring each of these two positions are considered. Finally, with an eye toward future research related to indeterminacy relations, further novel approaches grounded in category theory and intended to capture and reconceptualize the complementarity characteristics of quantum propositions are discussed in relation to the former
Subjective Logic and Arguing with Evidence
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The Laws of Thought
The Laws of Thought is an exploration of the deductive and inductive foundations of rational thought. The author here clarifies and defends Aristotle’s Three Laws of Thought, called the Laws of Identity, Non-contradiction and Exclusion of the Middle – and introduces two more, which are implicit in and crucial to them: the Fourth Law of Thought, called the Principle of Induction, and the Fifth Law of Thought, called the Principle of Deduction. This book is a thematic compilation drawn from past works by the author over a period of twenty-three years (1990-2013)
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