418 research outputs found
A Unique Continuation Result for Klein-Gordon Bisolutions on a 2-dimensional Cylinder
We prove a novel unique continuation result for weak bisolutions to the
massive Klein-Gordon equation on a 2-dimensional cylinder M. Namely, if such a
bisolution vanishes in a neighbourhood of a `sufficiently large' portion of a
2-dimensional surface lying parallel to the diagonal in the product manifold of
M with itself, then it is (globally) translationally invariant. The proof makes
use of methods drawn from Beurling's theory of interpolation. An application of
our result to quantum field theory on 2-dimensional cylinder spacetimes will
appear elsewhere.Comment: LaTeX2e, 9 page
Leap of Death
‘Leap of Death’ is collaborative, multi-media project by composer Robert Stillman, artist Anna Fewster, and bookbinder Sarah Bryant. It seeks to interpret archival material for the ‘lost’ 1929 F.W. Murnau film ‘4 Devils’. The main output of the project is a limited edition of 50 bookwork/LP’s that use letterpress text, trace-monotype print images, and recorded music to construct an abstract, non-linear ‘impression’ of the film’s narrative. The project also included a ‘live’ version of this work using projections of the bookwork text and imagery, and performance of the music by the ensemble The Archaic Future Players.
The wider research questions for this project include:
• Can archival research be carried out and disseminated as contemporary artistic/creative work? What is distinctive about such an approach (compared, for example, to scholarly research).
• How can creative content (i.e. narrative) in one form, like film, be translated into, or indeed extended by, other forms like still image, text, and music?
• How can ‘traditional’ media like slideshows, live/recorded music, or books present narrative structure in an ‘open’ (i.e. non-linear way?)
• How can a digital format (i.e. web) most effectively represent physical media (i.e. an artist’s bookwork)
Quantum energy inequalities in two dimensions
Quantum energy inequalities (QEIs) were established by Flanagan for the
massless scalar field on two-dimensional Lorentzian spacetimes globally
conformal to Minkowski space. We extend his result to all two-dimensional
globally hyperbolic Lorentzian spacetimes and use it to show that flat
spacetime QEIs give a good approximation to the curved spacetime results on
sampling timescales short in comparison with natural geometric scales. This is
relevant to the application of QEIs to constrain exotic spacetime metrics.Comment: 4 pages, REVTeX. This is an expanded version of a portion of
gr-qc/0409043. To appear in Phys Rev
On the spin-statistics connection in curved spacetimes
The connection between spin and statistics is examined in the context of
locally covariant quantum field theory. A generalization is proposed in which
locally covariant theories are defined as functors from a category of framed
spacetimes to a category of -algebras. This allows for a more operational
description of theories with spin, and for the derivation of a more general
version of the spin-statistics connection in curved spacetimes than previously
available. The proof involves a "rigidity argument" that is also applied in the
standard setting of locally covariant quantum field theory to show how
properties such as Einstein causality can be transferred from Minkowski
spacetime to general curved spacetimes.Comment: 17pp. Contribution to the proceedings of the conference "Quantum
Mathematical Physics" (Regensburg, October 2014
Quantum inequalities for the free Rarita-Schwinger fields in flat spacetime
Using the methods developed by Fewster and colleagues, we derive a quantum
inequality for the free massive spin- Rarita-Schwinger fields in
the four dimensional Minkowski spacetime. Our quantum inequality bound for the
Rarita-Schwinger fields is weaker, by a factor of 2, than that for the
spin- Dirac fields. This fact along with other quantum inequalities
obtained by various other authors for the fields of integer spin (bosonic
fields) using similar methods lead us to conjecture that, in the flat
spacetime, separately for bosonic and fermionic fields, the quantum inequality
bound gets weaker as the the number of degrees of freedom of the field
increases. A plausible physical reason might be that the more the number of
field degrees of freedom, the more freedom one has to create negative energy,
therefore, the weaker the quantum inequality bound.Comment: Revtex, 11 pages, to appear in PR
Quantum inequalities in two dimensional curved spacetimes
We generalize a result of Vollick constraining the possible behaviors of the
renormalized expected stress-energy tensor of a free massless scalar field in
two dimensional spacetimes that are globally conformal to Minkowski spacetime.
Vollick derived a lower bound for the energy density measured by a static
observer in a static spacetime, averaged with respect to the observers proper
time by integrating against a smearing function. Here we extend the result to
arbitrary curves in non-static spacetimes. The proof, like Vollick's proof, is
based on conformal transformations and the use of our earlier optimal bound in
flat Minkowski spacetime. The existence of such a quantum inequality was
previously established by Fewster.Comment: revtex 4, 5 pages, no figures, submitted to Phys. Rev. D. Minor
correction
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