Physicists From Argentina

"... spacetime as a concept leads to some … where the equations fail. This happens in the interiors of the black holes when spacetime somehow collapses ... And, also, most importantly it happened in the beginning of the Big Bang."

"It has been a long-standing challege for to construct a theory of quantum gravity. String theory is the leading candidate for a quantum theory of gravity. General Relativity has the seeds of its own destruction in it, since smooth can evolve into singular field configurations ... Classically this is not a problem if the singularities are hidden behind s ... since this means that nothing can come out from the region containing the singularity. However, Hawking showed, under very general assumptions, that quantum mechanics implies that black holes emit particles ... In his approximation this radiation is exactly thermal and contains no information about the state of the black hole. This leads to the , since particles can fall in carrying information but what comes out is featureless thermal radiation ... Hawking argued that this would lead to non-unitary evolution, so that one of the basic principles of quantum mechanics would have to be modified."

"In most situations, the contradictory requirements of quantum mechanics and general relativity are not a problem, because either the quantum effects or the gravitational effects are so small that they can be neglected or dealt with by approximations. When the of spacetime is very large, however, the quantum aspects of gravity become significant. It takes a very large or a great concentration of mass to produce much spacetime curvature. Even the curvature produced near the sun is exceedingly small compared with the amount needed for quantum gravity effects to become apparent. Though these effects are completely negligible now, they were very important in the beginning of the big bang, which is why a quantum theory of gravity is needed to describe how the big bang started. Such a theory is also important for understanding what happens at the center of black holes, because matter there is crushed into a region of extremely high curvature. Because gravity involves spacetime curvature, a quantum gravity theory will also be a theory of quantum spacetime ..."

"These of are very powerful. Let us recall the situation in flat space. If we have a massive in flat space then we can always boost to a . In AdS it is the same: if we consider the oscillating trajectory of a massive particle then we can "boost" to a frame where the particle is at rest. Thus, the moving particle does not know that is moving and, despite appearances, there is no "center" in AdS. The is part of the (as in the ) and there are several choices of Hamiltonian. Once we choose a Hamiltonian ... then we have chosen a "center" and a notion of the , in which a particle sits at this "center.""

"Interestingly, both quantum entanglement and s date back to two articles written by Albert Einstein and his collaborators in 1935. On the surface, the papers seem to deal with very different phenomena, and Einstein probably never suspected that there could be a connection between them. In fact, entanglement was a property of quantum mechanics that greatly bothered the German physicist, who called it How ironic that it now may offer a to extend his relativity theory to the quantum realm."

"Quotes 2008"

"The hardest thing is when you try to please someone who is not convinced."

"Trivial words but with great meaning."

"Un genio es alguien que descubre que la piedra que cae y la luna que no cae representan un solo y mismo fenómeno."

"The motto of science is not just Pauca but rather Plurima ex paucissimis — the most out of the least."

"At all times pseudoprofound aphorisms have been more popular than rigorous arguments."

"A definitely undesirable rationale sustaining the cult of simplicity is of a metaphysical nature: namely, the wish to attain the ultimate atoms of experience and/or reality ... this drive, which feeds metaphysical fundamentalism, is dangerous because it leads to postulating the final simplicity of some form of experience or some kind of substance thereby barring any inquiry into their structure."

"Logical positivism was progressive compared with the classical positivism of Ptolemy, Hume, d'Alembert, Compte, John Stuart Mill, and Ernst Mach. It was even more so by comparison with its contemporary rivals—, , , , , and existentialism. However, neo-positivism failed dismally to give a faithful account of science, whether natural or social. It failed because it remained anchored to sense-data and to a phenomenalist metaphysics, overrated the power of induction and underrated that of hypothesis, and denounced realism and materialism as metaphysical nonsense. Although it has never been practiced consistently in the advanced natural sciences and has been criticized by many philosophers, notably Popper (1959 [1935], 1963), logical positivism remains the tacit philosophy of many scientists. Regrettably, the anti-positivism fashionable in the metatheory of social science is often nothing but an excuse for sloppiness and wild speculation."

"We all would to know more and, at the same time, to receive less information. In fact, the problem of a worker in today's knowledge industry is not the scarcity of information but its excess. The same holds for professionals: just think of a physician or an executive, constantly bombarded by information that is at best irrelevant. In order to learn anything we need time. And to make time we must use information filters allowing us to ignore most of the information aimed at us. We must ignore much to learn a little."

"If one aims to judge political movements, their deeds are far more important than their speeches, which are often masking rather than revealing."

"When in the sciences or techniques one states that a certain problem is unsolvable, a rigorous demonstration of such unsolvability is required. And when a scientist submits an article to publication, the least that its referees demand is that it be intelligible. Why? Because rational beings long for understanding and because only clear statements are susceptible to be put to examination to verify whether they are true or false. In the Humanities it is the same, or it should be, but it is not always so. Nietzsche reproached John Stuart Mill's clarity. Henri Bergson, although an intuitionist himself, wrote clearly and declared that "clarity is the philosopher's courtesy". Obscurity is rude, because it assumes the interlocutor is incapable of understanding and dialoguing."

"Bunge: In September I will be 90 years old. Reporter: You look very youthful. Bunge: That's because I avoid alcohol, tobacco, and postmodernism."

"The fact that a great many scientists signed Faustian pacts with the war devil throughout the twentieth century has given science a bad name, and has discouraged many able youngsters from pursuing a scientific career."

"In academia much bogus knowledge is tolerated in the name of academic freedom – which is like allowing for the sale of contaminated food in the name of free enterprise. I submit that such tolerance is suicidal: that the serious students must be protected against the “anything goes” crowd."