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Search: authors:"Andrew B. Royston"

7 papers found.
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Holography for field theory solitons

We extend a well-known D-brane construction of the AdS/dCFT correspondence to non-abelian defects. We focus on the bulk side of the correspondence and show that there exists a regime of parameters in which the low-energy description consists of two approximately decoupled sectors. The two sectors are gravity in the ambient spacetime, and a six-dimensional supersymmetric Yang-Mills ...

Semiclassical framed BPS states

We provide a semiclassical description of framed BPS states in four-dimensional \( \mathcal{N}=2 \) super Yang-Mills theories probed by ’t Hooft defects, in terms of a supersymmetric quantum mechanics on the moduli space of singular monopoles. Framed BPS states, like their ordinary counterparts in the theory without defects, are associated with the L 2 kernel of certain Dirac ...

Revisiting soliton contributions to perturbative amplitudes

It is often said that soliton contributions to perturbative processes in QFT are exponentially suppressed by a form factor. We provide a derivation of this form factor by studying the soliton-antisoliton pair production amplitude for a class of scalar theories with generic soliton moduli. This reduces to the calculation of a matrix element in the quantum mechanics on the soliton ...

Some tree-level string amplitudes in the NSR formalism

We calculate tree level scattering amplitudes for open strings using the NSR formalism. We present a streamlined symmetry-based and pedagogical approach to the computations, which we first develop by checking two-, three-, and four-point functions involving bosons and fermions. We calculate the five-point amplitude for massless gluons and find agreement with an earlier result by ...

Scalar soliton quantization with generic moduli

We canonically quantize multi-component scalar field theories in the presence of solitons. This extends results of Tomboulis [1] to general soliton moduli spaces. We derive the quantum Hamiltonian, discuss reparameterization invariance and explicitly show how, in the semiclassical approximation, the dynamics of the full theory reduce to quantum mechanics on the soliton moduli ...

Brane bending and monopole moduli

We study intersecting brane systems that realize a class of singular monopole configurations in four-dimensional Yang-Mills-Higgs theory. Singular monopoles are solutions to the Bogomolny equation on \( {\mathrm{\mathbb{R}}}^3 \) with a prescribed number of singularities corresponding to the insertion of ’t Hooft defects. We use the brane construction to motivate a recent ...

Parameter counting for singular monopoles on ℝ3

We compute the dimension of the moduli space of gauge-inequivalent solutions to the Bogomolny equation on ℝ3 with prescribed singularities corresponding to the insertion of a finite number of ’t Hooft defects. We do this by generalizing the methods of C. Callias and E. Weinberg to the case of ℝ3 with a finite set of points removed. For a special class of Cartan-valued backgrounds ...