Re: [Phys-l] paper: "The quantum state cannot be interpreted statistically"

[Derek McKenzie <derek_s_mckenzie@hotmail.com>]

> Have y'all seen this?
>   http://lanl.arxiv.org/abs/1111.3328
>
> > The quantum state cannot be interpreted statistically
> > Matthew F. Pusey, Jonathan Barrett, Terry Rudolph
> > (Submitted on 14 Nov 2011)

For all the hype it's getting, I have to say I'm pretty disappointed with my first parse of this paper. For one thing, I really don't understand what they believe they have proved, and I don't think my confusion is all my fault.

For a paper tackling something so profound, the authors surely need to define their terms with impeccable clarity. Yet despite having read dozens of books and hundreds of papers on the foundations of quantum mechanics I am unable to understand early statements in the paper like "If the quantum state is a physical property of the system". It is not standard terminology to refer to a 'state' as a 'property', so I have no idea what this statement even means. In fact, I'm really not sure what they mean by 'property of a system' to begin with.

Given that the entire thesis of the paper is directed at such foundational concepts I am very frustrated that I can't work out what they mean by the concepts they are using.

I am reminded of Einstein's disappointment with the confused language used by Rosen and Podolsky in attempting to explain Einstein's thesis (his English wasn't too great at the time so he allowed them to write it up for him). By introducing unnecessary language like 'element of reality' they completely obscured Einstein's point, which he subsequently articulated with much greater clarity in (much less widely circulated) notes and correspondence.

Anyhow, if anybody finds a clearer exposition of the content of this paper I'd be very interested to see it. 

Derek