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Vincent Menet

Publications and source records attributed to Vincent Menet.

5 recordsLinked to original sources

A weakly non-abelian decay channel

We investigate non-abelian branes in curved space. We discuss solutions to the equations of motion of the transverse scalars when they are constant along the world-volume directions and obey an $\mathfrak{su}(2)$ or an $\mathfrak{su}(2)\oplus\mathfrak{su}(2)$ algebra. Motivated by the membrane version of the weak gravity conjecture, we specialise our results to non-abelian domain-wall D$(d-2)$ branes embedded in AdS$_d$ flux vacua. We find that they can be less self-attractive than their abelian counterpart, opening up a new decay-channel for vacua that resist all abelian domain-wall destabilisations. These branes come in two types, depending on whether their fuzziness involves the radial direction, or is purely internal. Only the latter can develop in vacua free from abelian decays. We illustrate our construction by embedding these branes in a variety of AdS vacua, destabilising some of them.

hep-th

Stability of non-supersymmetric vacua from calibrations

Supersymmetric vacua are protected from vacuum decay by energy positivity. No such argument is known for any non-supersymmetric vacua. In this paper, we try to extend to the latter a simpler argument based on calibrations, to at least protect them from decays mediated by D-brane bubbles, including their abelian bound states. We examine several classes of AdS$_4$ and AdS$_5$ solutions in type II string theory, including some new ones, involving coset spaces, sphere fibrations, K\"ahler--Einstein manifolds. Many of these vacua have resisted against all the decay channels we were able to assess. We also show how to use calibrations for the stability of D-branes already present in a non-supersymmetric solution.

hep-th

D-terms in Generalised Complex Geometry

Generalised Complex Geometry provides a natural interpretation of the $\mathcal{N}=1$ supersymmetry conditions for warped solutions of type II supergravity as differential equations on polyforms on the internal manifold. Written in this language the supersymmetry conditions correspond to calibration conditions for probe D-branes: D-string, domain-wall or space-filling branes, depending on the directions they span in the non-compact four-dimensional space. The BPS condition corresponding to the calibration of space-filling D-branes has been reformulated by Tomasiello, eliminating the explicit dependence on the metric. We generalise this derivation to the case of non-supersymmetric backgrounds violating the domain-wall and D-string calibration conditions. We use this reformulation to derive constraints that the ten-dimensional solutions with BPS space-filling sources must respect in order to dimensionally reduce to solutions of four-dimensional $\mathcal{N}=1$ supergravity with non-vanishing F-terms and potentially non-vanishing D-terms. We give the equations of motion for the class of type II vacua satisfying these constraints in the language of pure spinors. We investigate how restrictive these constraints are for the class of type IIB SU$(3)$ backgrounds with BPS space-filling O5-planes.

hep-th

New non-supersymmetric flux vacua from generalised calibrations

We construct a new class of non-supersymmetric ten-dimensional type II flux vacua, by studying first order differential equations which are deformations of the $\mathcal{N}=1$ supersymmetry conditions. We do so within the context of Generalised Complex Geometry, where there is a natural interpretation of the $\mathcal{N}=1$ supersymmetry conditions in terms of calibration conditions for probe D-branes, called D-string, domain-wall or space-filling branes, depending on them wrapping two, three or four non-compact dimensions. We focus on the class of non-supersymmetric vacua violating the D-string calibration condition, and write down their general equations of motion in the language of pure spinors. We solve them for a subclass of vacua, where the deformation of the calibration condition is dictated by the foliated geometry of the internal space. We also construct backgrounds violating both the domain-wall and D-string calibration conditions, generalising the one-parameter DWSB class of backgrounds introduced in L\"ust et al. We present several explicit solutions with SU$(2)$ and SU$(3)$ structures, and we investigate briefly their associated low energy effective theories.

hep-th

Integrable active atom interferometry

Active interferometers are designed to enhance phase sensitivity beyond the standard quantum limit by generating entanglement inside the interferometer. An atomic version of such a device can be constructed by means of a spinor Bose-Einstein condensate with an $F=1$ groundstate manifold in which spin-changing collisions create entangled pairs of $m=\pm1$ atoms. We use Bethe Ansatz techniques to find exact eigenstates and eigenvalues of the Hamiltonian that models such spin-changing collisions. Using these results, we express the interferometer's phase sensitivity, Fisher information, and Hellinger distance in terms of the Bethe rapidities. By evaluating these expressions we study scaling properties and the interferometer's performance under the full Hamiltonian that models the spin-changing collisions, i.e., without the idealising approximations of earlier works that force the model into the framework of SU(1,1) interferometry.

quant-ph