I feel quite grateful to the DZERO collaboration for publishing today in the Cornell arxiv the preprint of their search for neutral MSSM Higgs bosons in the tau-pair decay mode. Not more than 12 hours ago in fact I had been looking for a suitable figure which could summarize the status of searches for those particles, to help a student who is about to graduate; but had not found anything satisfactory.

This recent Nature article makes people jump up and down in classical, non-quantum jumps as we speak: “Experimental non-classicality of an indivisible quantum system”.

There are plenty of misleading news articles already, including here on Science2.0, about that this experiment is disproving classicality without even needing “spooky action at a distance” or entanglement. The message one often takes away is therefore that this new experiment may be the best proof yet, the most convenient disprove of hidden variables.

Quantum entanglement was strange when it was conceptualized.   It violated Einstein's famous speed limit in his Theory of Relativity and he called it spukhafte Fernwirkung - “spooky action at a distance” and sought to note the flaws in Heisenberg's uncertainty principle and the Copenhagen interpretation.   The result was the Einstein–Podolsky–Rosen paradox.
Continued from the last post.

Discounting the Bohmian song and dance, we are led to conclude that each electron does in some sense pass through both slits. But in what sense? Saying that an electron went through both slits cannot be equivalent to saying that the electron went through L and that it went through R, for to ascertain the truth of a conjunction we must individually ascertain the truths of its components, and we never find that an electron launched at G and detected at D has taken the left slit and that it has taken the right slit.
A paper describing the first evidence of top pair production in association with a energetic photon has just appeared on the Cornell Arxiv. This search has been performed by the CDF collaboration in a sample of 6 inverse femtobarns of proton-antiproton collisions.

There is nothing strange or particular about the fact that any hard production process at a hadron collider can produce, in addition with a massive state such as a top pair, additional energetic photons. That is because any charged particle involved in the process will have a small but finite chance of radiating electromagnetic energy, with a strength governed by our good-old fine-structure constant.
A great title is key to getting lots of views. For my blogs, ones with the fewest views include “Snarky Puzzle Answers”, and “Snarky Puzzle Answers 2”. Do I have high expectations for SPA 3, Revenge of the Nerds? Nope, I expect the community to be consistent. This is an observation, not a complaint, honest.

What is exciting to me is that I am asking questions and developing answers. I want to emphasize the plural. This is not a one trick pony (quaternions can do 3D rotations and nothing else of interest). Many different topics are being raised and looked at from odd angles. I didn’t have a plan to write these puzzles, but am glad they emerged from the blog writing process. Now back to the questions and their answers.

The Quantum Randi Challenge (QRC), first introduced here, exists in order to stop the spread of pseudo-science by simply teaching quantum mechanics. Here is the official version of the challenge (also published here and partially in Annals of Physics 339: 81-88). [We are still looking for people who can help to turn it into a multiplayer internet app.*]

What is a “Randi-type” challenge?

According to Feynman, the 2-slit experiment with electrons "has in it the heart of quantum mechanics" and "is impossible, absolutely impossible, to explain in any classical way". To begin with, it may not be amiss to inform the never-ending discussion of this experiment with a knowledge of the rules that go into calculating the predicted and observed interference pattern.

The mathematical formalism of quantum mechanics can be built up on the basis of the following rules. Suppose that you want to calculate the probability of a particular outcome of a measurement M2, given the outcome of am earlier measurement M1. Here is what you have to do:
The ATLAS Collaboration, one of the two high-energy physics experiments at the CERN Large Hadron Collider, has just produced updated results of their ongoing search for new heavy particles decaying into lepton pairs. They are now using up to 236 inverse picobarns of 7 TeV collisions, which is seven times more data than previous searches based on 2010 datasets. A seven-fold increase in data size grants a significant increase in sensitivity, so it is worth taking a look at what they see.

Quantum physics has proven that the world cannot be described by local realism. Therefore, Many-Worlds Interpretations (MWI) are now in vogue.

This is already wrong: Everett's is a relative state description, not necessarily a multiple worlds interpretation.