arXiv subjects

Tonnis ter Veldhuis

Publications and source records attributed to Tonnis ter Veldhuis.

7 recordsLinked to original sources

arXiv2025

Hidden Zeros in Exceptional Field Theories from Double Copy

It was recently discovered by Arkani-Hamed et al and Cao et al that the colour-ordered scattering amplitudes of Tr$(Φ^3)$, the non-linear sigma model and Yang-Mills-scalar vanish at specific loci. We build on this observation and demonstrate that, beyond colour ordering, scattering amplitudes can display higher-order hidden zeros. A first example are the flavour-paired amplitudes of gravity-coupled scalars, as a double copy of Yang-Mills-scalar. The other two cases are Dirac-Born-Infeld and the special Galileon, which are the natural generalisations of the non-linear sigma model with higher orders of the Adler zero. We demonstrate that the amplitudes of these theories all factorize into lower-point objects in the near-zero limit, and discuss their interpretation. Finally, we comment on the general picture of hidden zeros and prove their relation under the double copy.

hep-th↗

arXiv2024

Hybrid Goldstone Modes from the Double Copy Bootstrap

We perform a systematic classification of scalar field theories whose amplitudes admit a double copy formulation and identify two building blocks at 4-point and 13 at 5-point. Using the 4-point blocks as bootstrap seeds, this naturally leads to a single copy theory that is a gauged NLSM. Moreover, its double copy includes a novel theory that can be written in terms of Lovelock invariants of an induced metric, and includes Dirac-Born-Infeld and the special Galileon in specific limits. The amplitudes of these Goldstone modes have two distinct soft behaviour regimes, corresponding to a hybrid of non-linear symmetries.

hep-th↗

arXiv2023

$p$-brane Galilean and Carrollian Geometries and Gravities

We study $D$-dimensional $p$-brane Galilean geometries via the intrinsic torsion of their adapted connections. These non-Lorentzian geometries are examples of $G$-structures whose characteristic tensors consist of two degenerate ``metrics'' of ranks $(p+1)$ and $(D-p-1)$. We carry out the analysis in two different ways. In one way, inspired by Cartan geometry, we analyse in detail the space of intrinsic torsions (technically, the cokernel of a Spencer differential) as a representation of $G$, exhibiting for generic $(p,D)$ five classes of such geometries, which we then proceed to interpret geometrically. We show how to re-interpret this classification in terms of ($D-p-2$)-brane Carrollian geometries. The same result is recovered by methods inspired by similar results in the physics literature: namely by studying how far an adapted connection can be determined by the characteristic tensors and by studying which components of the torsion tensor do not depend on the connection. As an application, we derive a gravity theory with underlying $p$-brane Galilean geometry as a non-relativistic limit of Einstein--Hilbert gravity and discuss how it gives a gravitational realisation of some of the intrinsic torsion constraints found in this paper. Our results also have implications for gravity theories with an underlying ($D-p-2$)-brane Carrollian geometry.

hep-th↗

arXiv2018

Non-Perturbative One-Loop Effective Action for QED with Yukawa Couplings

We derive the one-loop effective action for scalar, pseudoscalar, and electromagnetic fields coupled to a Dirac fermion in an extension of QED with Yukawa couplings. Using the Schwinger proper-time formalism and zeta-function regularization, we calculate the full non-perturbative effective action to one loop in the constant background field approximation. Our result is non-perturbative in the external fields, and goes beyond existing results in the literature which treat only the first non-trivial order involving the pseudoscalar. The result has an even and odd part, which are related to the modulus and phase of the fermion functional determinant. The even contribution to the effective action involves the modulus of the effective Yukawa couplings and is invariant under global chiral transformations while the odd contribution is proportional to the angle between the scalar and pseudoscalar couplings. In different limits the effective action reduces either to the Euler-Heisenberg effective action or the Coleman-Weinberg potential. We also comment on the relationship between the odd part of the effective action and the chiral anomaly in QED.

hep-th↗

arXiv2017

Carroll versus Galilei Gravity

We consider two distinct limits of General Relativity that in contrast to the standard non-relativistic limit can be taken at the level of the Einstein-Hilbert action instead of the equations of motion. One is a non-relativistic limit and leads to a so-called Galilei gravity theory, the other is an ultra-relativistic limit yielding a so-called Carroll gravity theory. We present both gravity theories in a first-order formalism and show that in both cases the equations of motion (i) lead to constraints on the geometry and (ii) are not sufficient to solve for all of the components of the connection fields in terms of the other fields. Using a second-order formalism we show that these independent components serve as Lagrange multipliers for the geometric constraints we found earlier. We point out a few noteworthy differences between Carroll and Galilei gravity and give some examples of matter couplings.

hep-th↗

arXiv2001

Domain walls in supersymmetric QCD: The taming of the zoo

We provide a unified picture of the domain wall spectrum in supersymmetric QCD with Nc colors and Nf flavors of quarks in the (anti-) fundamental representation. Within the framework of the Veneziano-Yankielowicz-Taylor effective Lagrangian, we consider domain walls connecting chiral symmetry breaking vacua, and we take the quark masses to be degenerate. For Nf/Nc<1/2, there is one BPS saturated domain wall for any value of the quark mass m. For 1/2= m** there is no domain wall. We numerically determine m* and m** as a function of Nf/Nc, and we find that m** approaches a constant value in the limit that this ratio goes to one.

hep-th↗

arXiv2000

Direct and indirect limits on the electro-magnetic form factors of WIMPs

We use the results of direct and indirect searches for weakly interacting massive particles (WIMPs) to obtain bounds on various electro-magnetic form factors of WIMPs. The limits on the recoil signal in underground dark matter detection experiments, with standard assumptions about the density and r.m.s. velocity of WIMPs in the halo, can be translated into the following model-independent bounds on the magnetic dipole, electric dipole, quadrupole and anapole moments and the polarizability of WIMPs: mu/mu_n < 1.4 10^{-4}, d < 5 10^{-21}e cm, Q < 6 10^{-7}fm^2, a/mu_n < 3 10^{-2} fm, and chi < 5 10^{-8}fm^3 for a WIMP mass of 100 GeV. The limits on fluxes of highly energetic neutrinos produced in the annihilation of WIMPs in the center of the earth and the sun lead to somewhat stronger, but more model dependent bounds.

hep-ph↗