421 research outputs found
Interaction of molecular motors can enhance their efficiency
Particles moving in oscillating potential with broken mirror symmetry are
considered. We calculate their energetic efficiency, when acting as molecular
motors carrying a load against external force. It is shown that interaction
between particles enhances the efficiency in wide range of parameters. Possible
consequences for artificial molecular motors are discussed.Comment: 6 pages, 8 figure
Quantum Multiplexers, Parrondo Games, and Proper Quantization
A quantum logic gate of particular interest to both electrical engineers and
game theorists is the quantum multiplexer. This shared interest is due to the
facts that an arbitrary quantum logic gate may be expressed, up to arbitrary
accuracy, via a circuit consisting entirely of variations of the quantum
multiplexer, and that certain one player games, the history dependent Parrondo
games, can be quantized as games via a particular variation of the quantum
multiplexer. However, to date all such quantizations have lacked a certain
fundamental game theoretic property.
The main result in this dissertation is the development of quantizations of
history dependent quantum Parrondo games that satisfy this fundamental game
theoretic property. Our approach also yields fresh insight as to what should be
considered as the proper quantum analogue of a classical Markov process and
gives the first game theoretic measures of multiplexer behavior.Comment: Doctoral dissertation, Portland State University, 138 pages, 22
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Too good to be true: when overwhelming evidence fails to convince
Is it possible for a large sequence of measurements or observations, which
support a hypothesis, to counterintuitively decrease our confidence? Can
unanimous support be too good to be true? The assumption of independence is
often made in good faith, however rarely is consideration given to whether a
systemic failure has occurred.
Taking this into account can cause certainty in a hypothesis to decrease as
the evidence for it becomes apparently stronger. We perform a probabilistic
Bayesian analysis of this effect with examples based on (i) archaeological
evidence, (ii) weighing of legal evidence, and (iii) cryptographic primality
testing.
We find that even with surprisingly low systemic failure rates high
confidence is very difficult to achieve and in particular we find that certain
analyses of cryptographically-important numerical tests are highly optimistic,
underestimating their false-negative rate by as much as a factor of
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