Reeh-Schlieder Defeats Newton-Wigner: On alternative localization schemes in relativistic quantum field theory

Many of the "counterintuitive" features of relativistic quantum field theory have their formal root in the Reeh-Schlieder theorem, which in particular entails that local operations applied to the vacuum state can produce any state of the entire field. It is of great interest, then, that I.E. Segal and, more recently, G. Fleming (in a paper entitled "Reeh-Schlieder Meets Newton-Wigner") have proposed an alternative "Newton-Wigner" localization scheme that avoids the Reeh-Schlieder theorem. In this paper, I reconstruct the Newton-Wigner localization scheme and clarify the limited extent to which it avoids the counterintuitive consequences of the Reeh-Schlieder theorem. I also argue that neither Segal nor Fleming has provided a coherent account of the physical meaning of Newton-Wigner localization.Comment: 25 pages, LaTe

A note on information theoretic characterizations of physical theories

Clifton, Bub, and Halvorson [Foundations of Physics 33, 1561 (2003)] have recently argued that quantum theory is characterized by its satisfaction of three information-theoretic axioms. However, it is not difficult to construct apparent counterexamples to the CBH characterization theorem. In this paper, we discuss the limits of the characterization theorem, and we provide some technical tools for checking whether a theory (specified in terms of the convex structure of its state space) falls within these limits.Comment: 16 pages, LaTeX, Contribution to Rob Clifton memorial conferenc

Impact of culture on stigma related to help-seeking behavior in college students

textThough many college students in the United States experience distress that could be ameliorated through counseling, not everyone is willing to seek help. Some estimates report that only 11% of those who have a diagnosable problem in a given year seek professional services (Vogel, Wade, & Hackler, 2007). This suggests that a barrier exists preventing individuals who could benefit from seeking help from doing so. Stigma is an umbrella term used to describe the negative social implications, such as those associated with mental illness, that serve as a barrier between student need and contact with services. The gravity of stigma was validated in the 1999 surgeon general's report on mental health that identified that the fear of stigma deterred individuals from being aware of their illness, seeking subsequent help, and remaining in treatment (http:// www.mentalhealthcommission.gov; Satcher, 1999). Stigma against help-seeking is a result of many different factors including, but not limited to, culture, societal influences, formal versus informal help-seeking, and gender norms. Understanding that it is not feasible to adequately address each of the previous factors, this report reviews stigma related to help-seeking across cultures and aims to discuss how different cultural values can influence an individual's willingness to seek formal help. Strategies for intervention and stigma reduction are also discussed.Educational Psycholog

Momentum and Context

A sentence's meaning may depend on the state of motion of the speaker. I argue that this context-sensitivity blocks the inference from special relativity to four-dimensionalism

There is no invariant, four-dimensional stuff

Some philosophers say that in special relativity, four-dimensional stuff is invariant in some sense that three-dimensional stuff is not. I show that this claim is false

Are Rindler Quanta Real? Inequivalent particle concepts in quantum field theory

Philosophical reflection on quantum field theory has tended to focus on how it revises our conception of what a particle is. However, there has been relatively little discussion of the threat to the "reality" of particles posed by the possibility of inequivalent quantizations of a classical field theory, i.e., inequivalent representations of the algebra of observables of the field in terms of operators on a Hilbert space. The threat is that each representation embodies its own distinctive conception of what a particle is, and how a "particle" will respond to a suitably operated detector. Our main goal is to clarify the subtle relationship between inequivalent representations of a field theory and their associated particle concepts. We also have a particular interest in the Minkowski versus Rindler quantizations of a free Boson field, because they respectively entail two radically different descriptions of the particle content of the field in the very same region of spacetime. We shall defend the idea that these representations provide complementary descriptions of the same state of the field against the claim that they embody completely incommensurable theories of the field.Comment: 62 pages, LaTe

Complementarity of representations in quantum mechanics

We show that Bohr's principle of complementarity between position and momentum descriptions can be formulated rigorously as a claim about the existence of representations of the CCRs. In particular, in any representation where the position operator has eigenstates, there is no momentum operator, and vice versa. Equivalently, if there are nonzero projections corresponding to sharp position values, all spectral projections of the momentum operator map onto the zero element.Comment: 14 pages, LaTe