Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Casimir Effect and Global Theory of Boundary Conditions   The consistency of quantum field theories defined on domains with external
borders imposes very restrictive constraints on the type of boundary conditions
that the fields can satisfy. We analyse the global geometrical and topological
properties of the space of all possible boundary conditions for scalar quantum
field theories. The variation of the Casimir energy under the change of
boundary conditions reveals the existence of singularities generically
associated to boundary conditions which either involve topology changes of the
underlying physical space or edge states with unbounded below classical energy.
The effect can be understood in terms of a new type of Maslov index associated
to the non-trivial topology of the space of boundary conditions. We also
analyze the global aspects of the renormalization group flow, T-duality and the
conformal invariance of the corresponding fixed points.

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The categories of this paper are: astro-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: physics
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The categories of this paper are: stat
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: econ