Artículos con la etiqueta ‘experimentos’

Un universo “de juguete” revela que el tiempo es una ilusión

Por • 9 ene, 2014 • Category: Leyes

Por primera vez, un equipo de científicos ha conseguido poner a prueba las teorías matemáticas sobre la medida del tiempo de Page y Wootters en un sistema físico “de juguete”, es decir, compuesto sólo por dos fotones (que son las partículas elementales de la luz), informa Newscientist. Se hizo de la siguiente forma. Por un lado, los científicos, del Instituto Nacional de Investigación Meteorológica (INRiM) de Turín, en Italia, midieron el sistema de ambos fotones entrelazados desde “fuera” del universo de éstos, como haría un observador externo . Por otro, usaron uno de los dos fotones entrelazados a modo de “observador” del otro fotón o como “reloj”. Con éste midieron el estado (la polarización u orientación vertical u horizontal) del segundo fotón, mientras ambas partículas atravesaban dos vías independientes y de grosores variables, con los que se afectó a la polarización de los fotones y, por tanto, a su evolución. La medición fue posible porque el estado del primer fotón reflejaba el del segundo, merced al entrelazamiento cuántico.



The Recomputation Manifesto

Por • 3 jun, 2013 • Category: Leyes

Replication of scientific experiments is critical to the advance of science. Unfortunately, the discipline of Computer Science has never treated replication seriously, even though computers are very good at doing the same thing over and over again. Not only are experiments rarely replicated, they are rarely even replicable in a meaningful way. Scientists are being encouraged to make their source code available, but this is only a small step. Even in the happy event that source code can be built and run successfully, running code is a long way away from being able to replicate the experiment that code was used for. I propose that the discipline of Computer Science must embrace replication of experiments as standard practice. I propose that the only credible technique to make experiments truly replicable is to provide copies of virtual machines in which the experiments are validated to run. I propose that tools and repositories should be made available to make this happen. I propose to be one of those who makes it happen.



On the concepts of vacuum and mass and the search for higgs

Por • 9 dic, 2012 • Category: Leyes

Abstract: Some recollections on the recent history of the concepts of vacuum and mass and the search for higgs. According to the widely spread terminology the Higgs field permeates vacuum and serves as the origin of masses of all fundamental particles including the Higgs Boson — the higgs.



Fundamental Quantum Optics Experiments Conceivable With Satellites Reaching Relativistic Distances And Velocities

Por • 27 jun, 2012 • Category: Leyes

One of the great puzzles of modern science is that the laws that govern the universe on the largest scale are entirely different from the ones that govern on the smallest scale. That’s odd because all our intuition about the universe is that it ought to be internally consistent rather than at odds with itself. This is why physicists are inextricably wedded to the idea that relativity and quantum mechanics must be manifestations of a bigger and better idea that encompasses them both. The differences between general relativity and quantum mechanics are so great that every attempt to reconcile them has so far failed. However, these attempts have been entirely theoretical and that gives them limited utility.For example, physicists routinely measure the quantum phenomenon of entanglement by sending entangled pairs of photons from one location to another. In these experiments, the sender and receiver must both measure the polarisation of the photons, whether vertical or horizontal, for example. But that can only happen if both parties know which direction is up. That’s easy to specify when they are close together. But it becomes much harder if they are separated by distances over which the curvature of spacetime comes into play. The problem here is that the answer is ambiguous and depends on the path that each photon takes through spacetime. The experimenters can work this out by tracing the path of each photon back to their common source, if this is known. But then, how does each photon ‘know’ the path that the other has taken? Theorists can only guess. Another problem arises when these kinds of experiments are done with the sender and receiver travelling at relativistic speeds. This introduces the well known problem of determining the order of events, which Einstein famously showed depends on the observers’ points of view. That’s in stark contrast to the prediction of quantum mechanics. Here the measurement of one entangled photon instantly determines the result of a future measurement on the other, regardless of the distance between them. If special relativity ensures that the order of events is ambiguous, what gives? Once again, theorists are at a loss. Of course, the way to answer these questions is to test them and see.



Towards a realistic interpretation of quantum physics providing a physical model of the natural world

Por • 4 abr, 2012 • Category: Opinion

It is stressed the advantage of a realistic interpretation of quantum mechanics providing a physical model of the quantum world. After some critical comments on the most popular interpretations, the difficulties for a model are pointed out and possible solutions proposed. In particular the existence of discrete states, the quantum jumps, the alleged lack of objective properties, measurement theory, the probabilistic character of quantum physics, the wave-particle duality and the Bell inequalities are commented. It is conjectured that an intuitive picture of the quantum world could be obtained compatible with the quantum predictions for actual experiments, although maybe incompatible with alleged predictions for ideal, unrealizable, experiments.



A Historical Profile of the Higgs Boson

Por • 31 ene, 2012 • Category: Ciencia y tecnología

The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible production in e+ e-, pbar p and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which have been complemented by searches at the Fermilab Tevatron. The LHC has recently entered the hunt, excluding a Higgs boson over a large range of masses and revealing a tantalizing hint in the range 119 to 125 GeV, and there are good prospects that the existence or otherwise of the Higgs boson will soon be established. One of the most attractive possibilities is that the Higgs boson is accompanied by supersymmetry, though composite options have yet to be excluded. This article reviews some of the key historical developments in Higgs physics over the past half-century.



On Order and Randomness: A View from the Edge of Chaos

Por • 27 abr, 2011 • Category: Leyes

The recognition of the agency of the knower has enormously enriched our understanding of knowledge production. There is a growing realization that what we know about how we know affects our interpretation of reality. This realization informs the perspective of this paper. As a case study, the paper looks at the problem of randomness vs. determinism. It argues that this problem is not intrinsic to nature but is rather a product of the epistemological approach that does not pay attention to the process of the construction of knowledge. In contrast to the current one-sided solutions of the problem that represent reality as either random or deterministic, this paper argues that reality is neither random nor deterministic. Neither randomness nor determinism exists on its own.