3,652 research outputs found
An AdS_3 Dual for Minimal Model CFTs
We propose a duality between the 2d W_N minimal models in the large N 't
Hooft limit, and a family of higher spin theories on AdS_3. The 2d CFTs can be
described as WZW coset models, and include, for N=2, the usual Virasoro unitary
series. The dual bulk theory contains, in addition to the massless higher spin
fields, two complex scalars (of equal mass). The mass is directly related to
the 't Hooft coupling constant of the dual CFT. We give convincing evidence
that the spectra of the two theories match precisely for all values of the 't
Hooft coupling. We also show that the RG flows in the 2d CFT agree exactly with
the usual AdS/CFT prediction of the gravity theory. Our proposal is in many
ways analogous to the Klebanov-Polyakov conjecture for an AdS_4 dual for the
singlet sector of large N vector models.Comment: 33 pages LaTe
Mixed-symmetry massless gauge fields in AdS(5)
Free AdS(5) mixed-symmetry massless bosonic and fermionic gauge fields of
arbitrary spins are described by using su(2,2) spinor language. Manifestly
covariant action functionals are constructed and field equations are derived.Comment: 13 pages; v2: title changed, typos corrected, minor changes,
reference added; v3: minor changes, published versio
On the Irreducible BRST Quantization of Spin-5/2 Gauge Fields
Spin-5/2 gauge fields are quantized in an irreducible way within both the
BRST and BRST-anti-BRST manners. To this end, we transform the reducible
generating set into an irreducible one, such that the physical observables
corresponding to these two formulations coincide. The gauge-fixing procedure
emphasizes on the one hand the differences among our procedure and the results
obtained in the literature, and on the other hand the equivalence between our
BRST and BRST-anti-BRST approaches.Comment: 12 pages, latex 2.09, no figure
Magnetodielectric and magnetoelastic coupling in TbFe3(BO3)4
We have studied the magnetodielectric and magnetoelastic coupling in
TbFe3(BO3)4 single crystals by means of capacitance, magnetostriction and Raman
spectroscopy measurements. The data reveal strong magnetic field effects on the
dielectric constant and on the macroscopic sample length which are associated
to long range magnetic ordering and a field-driven metamagnetic transition. We
discuss the coupling of the dielectric, structural, and magnetic order
parameters and attribute the origin of the magnetodielectric coupling to phonon
mode shifts according to the Lyddane-Sachs-Teller (LST) relation.Comment: Accepted for publication in Physical Review
The incarnation of the Nersesyan-Tsvelik model in (NO)[Cu(NO3)3]
The topology of the magnetic interactions of the copper spins in the
nitrosonium nitratocuprate (NO)[Cu(NO3)3] suggests that it could be a
realization of the Nersesyan-Tsvelik model, whose ground state was argued to be
either a resonating valence bond (RVB) state or a valence bond crystal (VBC).
The measurement of thermodynamic and resonant properties reveals a behavior
inherent to low dimensional spin S = 1/2 systems and provides indeed no
evidence for the formation of long-range magnetic order down to 1.8 K.Comment: 12 pages, 6 figure
Holography, Unfolding and Higher-Spin Theory
Holographic duality is argued to relate classes of models that have
equivalent unfolded formulation, hence exhibiting different space-time
visualizations for the same theory. This general phenomenon is illustrated by
the higher-spin gauge theory shown to be dual to the theory of 3d
conformal currents of all spins interacting with 3d conformal higher-spin
fields of Chern-Simons type. Generally, the resulting 3d boundary conformal
theory is nonlinear, providing an interacting version of the 3d boundary sigma
model conjectured by Klebanov and Polyakov to be dual to the HS theory
in the large limit. Being a gauge theory it escapes the conditions of the
theorem of Maldacena and Zhiboedov, which force a 3d boundary conformal theory
to be free. Two reductions of particular higher-spin gauge theories where
boundary higher-spin gauge fields decouple from the currents and which have
free boundary duals are identified. Higher-spin holographic duality is also
discussed for the cases of and duality between higher-spin
theories and nonrelativistic quantum mechanics. In the latter case it is shown
in particular that () geometry in the higher-spin setup is dual to
the (inverted) harmonic potential in the quantum-mechanical setup.Comment: 57 pages, V2: Acknowledgements, references, comments, clarifications
and new section on reductions of particular HS theories associated with free
boundary theories are added. Typos corrected, V3. Minor corrections:
clarification in section 9 is added and typos correcte
Effective action in a higher-spin background
We consider a free massless scalar field coupled to an infinite tower of
background higher-spin gauge fields via minimal coupling to the traceless
conserved currents. The set of Abelian gauge transformations is deformed to the
non-Abelian group of unitary operators acting on the scalar field. The gauge
invariant effective action is computed perturbatively in the external fields.
The structure of the various (divergent or finite) terms is determined. In
particular, the quadratic part of the logarithmically divergent (or of the
finite) term is expressed in terms of curvatures and related to conformal
higher-spin gravity. The generalized higher-spin Weyl anomalies are also
determined. The relation with the theory of interacting higher-spin gauge
fields on anti de Sitter spacetime via the holographic correspondence is
discussed.Comment: 40 pages, Some errors and typos corrected, Version published in JHE
The GHZ/W-calculus contains rational arithmetic
Graphical calculi for representing interacting quantum systems serve a number
of purposes: compositionally, intuitive graphical reasoning, and a logical
underpinning for automation. The power of these calculi stems from the fact
that they embody generalized symmetries of the structure of quantum operations,
which, for example, stretch well beyond the Choi-Jamiolkowski isomorphism. One
such calculus takes the GHZ and W states as its basic generators. Here we show
that this language allows one to encode standard rational calculus, with the
GHZ state as multiplication, the W state as addition, the Pauli X gate as
multiplicative inversion, and the Pauli Z gate as additive inversion.Comment: In Proceedings HPC 2010, arXiv:1103.226
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