1,922,147 research outputs found

    Neutrino Oscillations from Strings and Other Funny Things

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    I will discuss three related unconventional ways to generate neutrino oscillations (1)Equivalence principle violation by the string dilaton field (i2)Violation of Lorentz Invariance and (3) Equivalence principle violation through a non-universal tensor neutrino-gravity coupling. These unorthodox neutrino oscillation mechanisms are shown to be viable at the level of our present experimental knowledge and demonstrate that neutrino oscillations can probe very profound questions

    A Generalization of Chetaev's Principle for a Class of Higher Order Non-holonomic Constraints

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    The constraint distribution in non-holonomic mechanics has a double role. On one hand, it is a kinematic constraint, that is, it is a restriction on the motion itself. On the other hand, it is also a restriction on the allowed variations when using D'Alembert's Principle to derive the equations of motion. We will show that many systems of physical interest where D'Alembert's Principle does not apply can be conveniently modeled within the general idea of the Principle of Virtual Work by the introduction of both kinematic constraints and variational constraints as being independent entities. This includes, for example, elastic rolling bodies and pneumatic tires. Also, D'Alembert's Principle and Chetaev's Principle fall into this scheme. We emphasize the geometric point of view, avoiding the use of local coordinates, which is the appropriate setting for dealing with questions of global nature, like reduction.Comment: 27 pages. Journal of Mathematical Physics (to zappear

    How should one define entropy production for nonequilibrium quantum spin systems?

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    This paper discusses entropy production in nonequilibrium steady states for infinite quantum spin systems. Rigorous results have been obtained recently in this area, but a physical discussion shows that some questions of principle remain to be clarified.Comment: 8 page

    Quantum like modelling of decision making: quantifying uncertainty with the aid of the Heisenberg-Robertson inequality

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    This paper contributes to quantum-like modeling of decision making (DM) under uncertainty through application of Heisenberg’s uncertainty principle (in the form of the Robertson inequality). In this paper we apply this instrument to quantify uncertainty in DM performed by quantum-like agents. As an example, we apply the Heisenberg uncertainty principle to the determination of mutual interrelation of uncertainties for “incompatible questions” used to be asked in political opinion pools. We also consider the problem of representation of decision problems, e.g., in the form of questions, by Hermitian operators, commuting and noncommuting, corresponding to compatible and incompatible questions respectively. Our construction unifies the two different situations (compatible versus incompatible mental observables), by means of a single Hilbert space and of a deformation parameter which can be tuned to describe these opposite cases. One of the main foundational consequences of this paper for cognitive psychology is formalization of the mutual uncertainty about incompatible questions with the aid of Heisenberg’s uncertainty principle implying the mental state dependence of (in)compatibility of questions

    Spatial Theory, Temporality and Public Action

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    Innovation and information combined with ICTs constitute a new framework which questions the theories on the functioning of classic space and stresses the need to think of new frames. The principle of acentrality proposed here highlights the role of politics in the structuring of space, as well as the role of temporality. For public planning policies to be relevant, acentrality and temporality must be taken into account
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