Author Archives: Mateus Araújo

State estimation is dead. Long live purification

I have just been to Perimeter Institute, by generous invitation of Thomas Galley. I gave a talk there about my recent-ish paper, Probability in two deterministic universes. Since I have already blogged about it here, I’m not writing about it … Continue reading

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How to manipulate numbers and get any result you want

This post hast little to do with physics, let alone quantum mechanics; I’m just writing it because I saw reports in the media about a study done by three German professors that had the incredible conclusion that electric vehicles emit … Continue reading

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The many-worlds interpretation of objective probability

Philosophers really like problems. The more disturbing and confusing the better. If there’s one criticism you cannot levy at them is that they are not willing to tackle the difficult issues. I have argued with philosophers endlessly about Bell’s theorem, … Continue reading

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The Born rule is obvious

Philip Ball has just published an excellent article in the Quanta magazine about two recent attempts at understanding the Born rule: one by Masanes, Galley, and Müller, where they derive the Born rule from operational assumptions, and another by Cabello, … Continue reading

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The flaw in Frauchiger and Renner’s argument

When the Frauchiger-Renner argument first came out I posted a favourable review, where I corrected the mistake in the presentation without even remarking on it. But since the authors decided to insist on the mistake, I feel the need to … Continue reading

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Royal Society Open Science is not a serious journal

I’ve just seen that Open Science, a new journal by the prestigious Royal Society, published the article Quantum correlations are weaved by the spinors of the Euclidean primitives, by Joy Christian. The article, as numerous others by the same author, … Continue reading

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Understanding Bell’s theorem part 4: the counterfactual version

I was recently leafing through the great book Quantum Computation and Quantum Information, and noticed that the version of Bell’s theorem it presents is not any of those I wrote about in my three posts about Bell’s theorem, but rather … Continue reading

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Measurement results depend on the observer

In today’s arXiv appeared a nice paper by Časlav Brukner, my former PhD supervisor. Its central claim is that one cannot have observer-independent measurement results in quantum mechanics, which I bet you disagree with. But if you think a bit … Continue reading

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A frenquentist’s dream

I’m frequently told that probabilities are the limit of relative frequencies for an infinite number of repetitions. It sounds nice: it defines a difficult concept – probabilities – in terms of a simple one – frequencies – and even gives … Continue reading

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Mixed states and true randomness

Recently two nice papers appeared on the arXiv, the most recent by Galley and Masanes, and the oldest by López Grande et al.. They are both – although a bit indirectly – about the age old question of the equivalence … Continue reading

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