Month: November 2012

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I’m an expert

Two expected, but long awaited events happened on my birthday. One: I found out that my Phd was approved, so no more bureaucratic shit regarding that. Two: The review paper on discord and similar quantities was finally published. This sums up about one and a half years’ work spent on reading, writing and rewriting this review with my collaborators.  Two versions have been posted on  arXiv  since the end of last year. The latest one, posted in August, is pretty much the published version.

I will soon post something longer about discord and non-classical correlations, for now it is enough to say that quantum theory allows more general correlations then a classical theory.  Entanglement is the best example of these types of correlations, but as it turns out there are unentangled systems with non-classical correlations. Quantum discord captures entanglement and more (but not everything).

Since the beginning of the century (i.e 12 years ago) people started studying these kinds of correlations “beyond” entanglement in various forms and physical scenarios. The area exploded about 5 years ago and discord became a “hot” topic. The review includes almost all the work done on the subject until the end of 2011. discord was studied in so many different scenarios like quantum information, thermodynamics, many body systems, relativistic quantum information and others which made work on this review so much fun, on the one hand, but a lot of work on the other.

 

 

 

 

 

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Betting on Science

In case you want to put your money where your mouth is on future predictions, this website lets you bet on a whole bunch of weird shit, from finding supersymmetric particles before the end of this or next year and the discovery of extraterrestrial life to the amount of snow in central park.

They give a 1% chance that Hamas will recognize Israel before Midnight december 2012 a 6% chance that the US or Israel will attack Iran before the end of the year and a 49% chance it will happen before the end of next year.

 

 

 

 

 

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Faster than light quantum information

A cool new paper appeared in Nature Physics this week and made a lot of waves (at least on my facebook feed).

In this paper titled “Quantum non-locality based on finite-speed causal influences leads to superluminal signalling” the authors show a method for testing if the “weird” effects of entanglement such as the violation of Bell inequalities can be explained using a faster then light source for exchanging information.

The main problem with these kinds of theories is that the usual Bell experiments can at best put a lower bound on the speed of exchanging this kind of information. The way to overcome this problem is to look at Bell violations in a 4 party system. The result of the paper is that one can perform a test that requires the speed of these causal influences to be infinite.

http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2460.html