arXiv subjects

A. C. Petkou

Publications and source records attributed to A. C. Petkou.

25 records · Page 2Linked to original sources

arXiv2000

The trace anomaly of the (2,0) tensor multiplet in background gauge fields

We study the trace anomaly of the (2,0) tensor multiplet in d=6 in the presence of a background SO(5) vector field acting as a source for the R-current. Using both a free-field theory calculation and AdS_7/CFT_6 correspondence, we find that only one of the two possible anomaly structures is non-zero and that its coefficient at strong-coupling differs by the well-known overall factor 4N^3 from the corresponding weak coupling result. We also discuss the relevance of our result to studies of the R-current anomaly in the (2,0) multiplet.

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arXiv2000

On the thermodynamics of the 2+1 dimensional Gross-Neveu model with complex chemical potential

We study the thermodynamics of the 2+1 dimensional Gross-Neveu model in the presence of a chemical potential by introducing a representation for the canonical partition function which encodes both real and imaginary chemical potential cases. It is pointed out that the latter case probes the thermodynamics of the possible anyon-like excitations in the spectrum. It is also intimately connected to the breaking of the discrete Z-symmetry of a U(1) gauge theory coupled to the Gross-Neveu model at finite temperature, which we interpret as signaling anyon deconfinement. Finally, the chiral properties of the model in the presence of an imaginary chemical potential are discussed and analytical results for the free-energy density at the transition points are presented.

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arXiv2000

A note on R-currents and trace anomalies in the (2,0) tensor multiplet in d=6 and AdS/CFT correspondence

We discuss the two- and three-point functions of the SO(5) R-current of the (2,0) tensor multiplet in d=6, using AdS/CFT correspondence as well as a free field realization. The results obtained via AdS/CFT correspondence coincide with the ones from a free field calculation up to an overall 4N^3 factor. This is the same factor found recently in studies of the two- and three-point functions of the energy momentum tensor in the (2,0) theory. We also connect our results to the trace anomaly in d=6 in the presence of external vector fields and briefly discuss their implications.

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arXiv2000

A note on the analyticity of AdS scalar exchange graphs in the crossed channel

We discuss the analytic properties of AdS scalar exchange graphs in the crossed channel. We show that the possible non-analytic terms drop out by virtue of non-trivial properties of generalized hypergeometric functions. The absence of non-analytic terms is a necessary condition for the existence of an operator product expansion for CFT amplitudes obtained from AdS/CFT correspondence.

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arXiv1999

On the Free-Energy of Three-Dimensional CFTs and Polylogarithms

We study the O(N) vector model and the U(N) Gross-Neveu model with fixed total fermion number, in three dimensions. Using non-trivial polylogarithmic identities, we calculate the large-N renormalized free-energy density of these models, at their conformal points in a ``slab'' geometry with one finite dimension of length L. We comment on the possible implications of our results.

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arXiv1998

Finite-Size Effects and Operator Product Expansions in a CFT for d>2

The large momentum expansion for the inverse propagator of the auxiliary field $λ(x)$ in the conformally invariant O(N) vector model is calculated to leading order in 1/N, in a strip-like geometry with one finite dimension of length $L$ for $2<d<4$. Its leading terms are identified as contributions from $λ(x)$ itself and the energy momentum tensor, in agreement with a previous calculation based on conformal operator product expansions. It is found that a non-trivial cancellation takes place by virtue of the gap equation. The leading coefficient of the energy momentum tensor contribution is shown to be related to the free energy density.

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arXiv1995

C_{T} and C_{J} up to next-to-leading order in 1/N in the Conformally Invariant O(N) Vector Model for 2<d<4

Using Operator Product Expansions and a graphical ansatz for the four-point function of the fundamental field ϕ^α(x) in the conformally invariant O(N) vector model, we calculate the next-to-leading order in 1/N values of the quantities C_{T} and C_{J}. We check the results against what is expected from possible generalisations of the C- and k-theorems in higher dimensions and also against known three-loop calculations in a O(N) invariant ϕ^{4} theory for d=4-ε.

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