Publications

Journal article

Borsten L, Marrani A, Pope CN, Stelle Ket al., 2022,

Introduction to the special issue dedicated to Michael J. Duff FRS on the occasion of his 70th birthday

, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 478, ISSN: 1364-5021

Journal article

Collaboration SPIDER, Ade PAR, Amiri M, Benton SJ, Bergman AS, Bihary R, Bock JJ, Bond JR, Bonetti JA, Bryan SA, Chiang HC, Contaldi CR, Doré O, Duivenvoorden AJ, Eriksen HK, Farhang M, Filippini JP, Fraisse AA, Freese K, Galloway M, Gambrel AE, Gandilo NN, Ganga K, Gualtieri R, Gudmundsson JE, Halpern M, Hartley J, Hasselfield M, Hilton G, Holmes W, Hristov VV, Huang Z, Irwin KD, Jones WC, Karakci A, Kuo CL, Kermish ZD, Leung JS-Y, Li S, Mak DSY, Mason PV, Megerian K, Moncelsi L, Morford TA, Nagy JM, Netterfield CB, Nolta M, O'Brient R, Osherson B, Padilla IL, Racine B, Rahlin AS, Reintsema C, Ruhl JE, Runyan MC, Ruud TM, Shariff JA, Shaw EC, Shiu C, Soler JD, Song X, Trangsrud A, Tucker C, Tucker RS, Turner AD, List JFVD, Weber AC, Wehus IK, Wen S, Wiebe DV, Young EYet al., 2022,

A constraint on primordial B-modes from the first flight of the spider balloon-borne telescope

, The Astrophysical Journal: an international review of astronomy and astronomical physics, Vol: 927, Pages: 1-26, ISSN: 0004-637X

We present the first linear polarization measurements from the 2015long-duration balloon flight of SPIDER, an experiment designed to map thepolarization of the cosmic microwave background (CMB) on degree angular scales.Results from these measurements include maps and angular power spectra fromobservations of 4.8% of the sky at 95 and 150 GHz, along with the results ofinternal consistency tests on these data. While the polarized CMB anisotropyfrom primordial density perturbations is the dominant signal in this region ofsky, Galactic dust emission is also detected with high significance; Galacticsynchrotron emission is found to be negligible in the SPIDER bands. We employtwo independent foreground-removal techniques in order to explore thesensitivity of the cosmological result to the assumptions made by each. Theprimary method uses a dust template derived from Planck data to subtract theGalactic dust signal. A second approach, employing a joint analysis of SPIDERand Planck data in the harmonic domain, assumes a modified-blackbody model forthe spectral energy distribution of the dust with no constraint on its spatialmorphology. Using a likelihood that jointly samples the template amplitude and$r$ parameter space, we derive 95% upper limits on the primordialtensor-to-scalar ratio from Feldman-Cousins and Bayesian constructions, finding$r<0.11$ and $r<0.19$, respectively. Roughly half the uncertainty in $r$derives from noise associated with the template subtraction. New data at 280GHz from SPIDER's second flight will complement the Planck polarization maps,providing powerful measurements of the polarized Galactic dust emission.

Journal article

Chen CY-R, de Rham C, Margalit A, Tolley AJet al., 2022,

A cautionary case of casual causality

, The Journal of High Energy Physics, Vol: 25, Pages: 1-40, ISSN: 1029-8479

We distinguish between the notions of asymptotic causality and infrared causality for gravitational effective field theories, and show that the latter gives constraints consistent with gravitational positivity bounds. We re-explore the scattering of gravitational waves in a spherically symmetric background in the EFT of gravity in D ≥ 5, for which the leading-order correction to Einstein gravity is determined by the Gauss-Bonnet operator. We reproduce the known result that the truncated effective theory exhibits apparent time advances relative to the background geometry for specific polarisations, which naively signal a violation of causality. We show that by properly identifying the regime of validity of the effective theory, the apparent time advance can be shown to be unresolvable. To illustrate this, we identify specific higher-dimension operators in the EFT expansion which become large for potentially resolvable time advances, rendering the EFT expansion invalid. Our results demonstrate how staying within the confines of the EFT, neither infrared nor asymptotic causality are ever violated for Einstein-Gauss-Bonnet gravity, no matter how low the scale, and furthermore its causality can be understood without appealing to a precise UV completion such as string theory.

Journal article

Golat S, Contaldi CR, 2022,

All-sky analysis of astrochronometric signals induced by gravitational waves

, Physical Review D, Vol: 105, Pages: 1-15, ISSN: 2470-0010

We introduce a unified spin-weighted formalism to describe both timing and astrometric perturbations induced on astrophysical point sources by gravitational waves using a complex spin field on the sphere. This allows the use of spin-weighted spherical harmonics to analyze “astrochronometric” observables. This approach simplifies the interpretation and simulation of anisotropies induced in the observables by gravitational waves. It also allows a simplified derivation of angular cross-spectra of the observables and their relationship with generalized Hellings-Downs correlation functions. The spin-weighted formalism also allows an explicit connection between correlation components and the spin of gravitational wave polarizations and any presence of chirality. We also calculate expected signal-to-noise ratios for observables to compare the utility of timing and deflection observables.

Journal article

de Rham C, Garcia-Saenz S, Heisenberg L, Pozsgay Vet al., 2022,

Cosmology of extended proca-nuevo

, Journal of Cosmology and Astroparticle Physics, Vol: 2022, Pages: 1-50, ISSN: 1475-7516

Proca-Nuevo is a non-linear theory of a massive spin-1 field which enjoys a non-linearly realized constraint that distinguishes it among other generalized vector models. We show that the theory may be extended by the addition of operators of the Generalized Proca class without spoiling the primary constraint that is necessary for consistency, allowing to interpolate between Generalized Proca operators and Proca-Nuevo ones. The constraint is maintained on flat spacetime and on any fixed curved background. Upon mixing extended Proca-Nuevo dynamically with gravity, we show that the constraint gets broken in a Planck scale suppressed way. We further prove that the theory may be covariantized in models that allow for consistent and ghost-free cosmological solutions. We study the models in the presence of perfect fluid matter, and show that they describe the correct number of dynamical variables and derive their dispersion relations and stability criteria. We also exhibit, in a specific set-up, explicit hot Big Bang solutions featuring a late-time self-accelerating epoch, and which are such that all the stability and subluminality conditions are satisfied and where gravitational waves behave precisely as in General Relativity.

Journal article

Dowker F, Wilkes H, 2022,

An argument for strong positivity of the decoherence functional in the path integral approach to the foundations of quantum theory

, AVS Quantum Science, Vol: 4, Pages: 012601-012601, ISSN: 2639-0213

We give an argument for strong positivity of the decoherence functional as the correct, physical positivity condition in formulations of quantum theory based fundamentally on the path integral. We extend to infinite systems work by Boës and Navascués that shows that the set of strongly positive quantum systems is maximal among sets of systems that are closed under tensor product composition. We show further that the set of strongly positive quantum systems is the unique set that is maximal among the sets that are closed under tensor product composition.I. INTRODUCTION

Working paper

Skrzypek T, Tseytlin AA, 2022,

On type 0 string theory in solvable RR backgrounds

, Publisher: ArXiv

Motivated by a possibility of solving non-supersymmetric type 0 string theoryin $AdS_5 \times S^5$ background using integrability, we revisit theconstruction of type 0 string spectrum in some solvable examples of backgroundswith RR fluxes that are common to type IIB and type 0B theories. The presenceof RR fluxes requires the use of a Green-Schwarz description for type 0 stringtheory. Like in flat space, the spectrum of type 0 theory can be derived fromthe type II theory spectrum by a $(-1)^F$ orbifolding, i.e. combining theuntwisted sector where GS fermions are periodic with the twisted sector whereGS fermions are antiperiodic (and projecting out all spacetime fermionicstates). This construction of the type 0 spectrum may also be implemented usinga Melvin background that allows to continuously interpolate between the type IIand type 0 theories. As an illustration, we discuss the type 0B spectrum in thepp-wave background which is the Penrose limit of $AdS_5 \times S^5$ with RR5-form flux and also in the pp-wave background which is the Penrose limit of$AdS_3 \times S^3 \times T^4$ supported by mixed RR and NSNS 3-form fluxes. Weshow that increasing the strength of the RR flux increases the value of theeffective normal ordering constant (which determines the mass of the type 0tachyon) and thus effectively decreases the momentum-space domain ofinstability of the ground state. We also comment on the semiclassical sector ofstates of type 0B theory in $AdS_5 \times S^5$.

Working paper

Beccaria M, Giombi S, Tseytlin A, 2022,

Wilson loop in general representation and RG flow in 1d defect QFT

The generalized Wilson loop operator interpolating between the supersymmetric and the ordinary Wilson loop in N=4 SYM theory provides an interesting example of renormalization group flow on a line defect: the scalar coupling parameter ζ has a non-trivial beta function and may be viewed as a running coupling constant in a 1d defect QFT. In this paper we continue the study of this operator, generalizing previous results for the beta function and Wilson loop expectation value to the case of an arbitrary representation of the gauge group and beyond the planar limit. Focusing on the scalar ladder limit where the generalized Wilson loop reduces to a purely scalar line operator in a free adjoint theory, and specializing to the case of the rank k symmetric representation of SU(N), we also consider a certain semiclassical limit where k is taken to infinity with the product kζ2 fixed. This limit can be conveniently studied using a 1d defect QFT representation in terms of N commuting bosons. Using this representation, we compute the beta function and the circular loop expectation value in the large k limit, and use it to derive constraints on the structure of the beta function for general representation. We discuss the corresponding 1d RG flow and comment on the consistency of the results with the 1d defect version of the F-theorem.

Journal article

Bento BV, Dowker F, Zalel S, 2022,

If time had no beginning: growth dynamics for past-infinite causal sets

, Classical and Quantum Gravity, Vol: 39, ISSN: 0264-9381

We explore whether the growth dynamics paradigm of causal set theory is compatible with past-infinite causal sets. We modify the classical sequential growth dynamics of Rideout and Sorkin to accommodate growth 'into the past' and discuss what form physical constraints such as causality could take in this new framework. We propose convex-suborders as the 'observables' or 'physical properties' in a theory in which causal sets can be past-infinite and use this proposal to construct a manifestly covariant framework for dynamical models of growth for past-infinite causal sets.

Journal article

Acharya B, Alexandre J, Benes P, Bergmann B, Bertolucci S, Bevan A, Branzas H, Burian P, Campbell M, Cho YM, de Montigny M, De Roeck A, Ellis JR, El Sawy M, Fairbairn M, Felea D, Frank M, Gould O, Hays J, Hirt AM, Ho DL-J, Hung PQ, Janecek J, Kalliokoski M, Korzenev A, Lacarrere DH, Leroy C, Levi G, Lionti A, Maulik A, Margiotta A, Mauri N, Mavromatos NE, Mermod P, Millward L, Mitsou VA, Ostrovskiy I, Ouimet P-P, Papavassiliou J, Parker B, Patrizii L, Pavalas GE, Pinfold JL, Popa LA, Popa V, Pozzato M, Pospisil S, Rajantie A, de Austri RR, Sahnoun Z, Sakellariadou M, Santra A, Sarkar S, Semenoff G, Shaa A, Sirri G, Sliwa K, Soluk R, Spurio M, Staelens M, Suk M, Tenti M, Togo V, Tuszyn'ski JA, Upreti A, Vento V, Vives Oet al., 2022,

Search for magnetic monopoles produced via the Schwinger mechanism

, NATURE, Vol: 602, Pages: 63-+, ISSN: 0028-0836

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Citations: 15

Journal article

Alberte L, de Rham C, Jaitly S, Tolley AJet al., 2022,

Reverse Bootstrapping: IR Lessons for UV Physics

, PHYSICAL REVIEW LETTERS, Vol: 128, ISSN: 0031-9007

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Citations: 22

Journal article

Arvanitakis AS, Hohm O, Hull C, Lekeu Vet al., 2022,

Homotopy transfer and effective field theory II: strings and double field theory

, Fortschritte Der Physik/Progress of Physics, Vol: 70, Pages: 1-26, ISSN: 0015-8208

We continue our study of effective field theory via homotopy transfer ofL∞-algebras, and apply it to tree-level non-Wilsonian effective actions of thekind discussed by Sen in which the modes integrated out are comparable inmass to the modes that are kept. We focus on the construction of effectiveactions for string states at fixed levels and in particular on the construction ofweakly constrained double field theory. With these examples in mind, wediscuss closed string theory on toroidal backgrounds and resolve some subtleissues involving vertex operators, including the proper form of cocycle factorsand of the reflector state. This resolves outstanding issues concerning theconstruction of covariant closed string field theory on toroidal backgrounds.The weakly constrained double field theory is formally obtained from closedstring field theory on a toroidal background by integrating out all but the‘doubly massless’ states and homotopy transfer then gives a prescription fordetermining the theory’s vertices and symmetries. We also discuss consistenttruncation in the context of homotopy transfer.

Journal article

Alday LF, Chester SM, Raj H, 2022,

ABJM at strong coupling from M-theory, localization, and Lorentzian inversion

, Journal of High Energy Physics, Vol: 2022

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We study the stress tensor multiplet four-point function in the 3d maximally supersymmetric ABJ(M) theory with Chern-Simons level <jats:italic>k</jats:italic> = 2, which in the large <jats:italic>N</jats:italic> limit is holographically dual to weakly coupled M-theory on <jats:italic>AdS</jats:italic><jats:sub>4</jats:sub> × <jats:italic>S</jats:italic><jats:sup>7</jats:sup><jats:italic>/</jats:italic>ℤ<jats:sub>2</jats:sub>. We use the Lorentzian inversion to compute the 1-loop correction to this holographic correlator coming from Witten diagrams with supergravity <jats:italic>R</jats:italic> and the first higher derivative correction <jats:italic>R</jats:italic><jats:sup>4</jats:sup> vertices, up to a finite number of contact terms that contribute to low spins where the inversion formula does not converge. We find a precise match with the corresponding terms in the 11d M-theory S-matrix by taking the flat space limit, which is not sensitive to these contact terms. We then conjecturally fix these contact terms by analytically continuing the inversion formula below its expected range of convergence, and verify this conjecture using supersymmetric localization. Finally, we compare some of the 1-loop CFT data to non-perturbative in <jats:italic>N</jats:italic> bounds from the numerical conformal bootstrap, which we compute at unprecedently high accuracy, and find that the 1-loop corrections saturate the bounds in the large <jats:italic>N</jats:italic> regime, which extends the previously observed match at tree level.</jats:p>

Journal article

Acharya B, Alexandre J, Benes P, Bergmann B, Bertolucci S, Bevan A, Branzas H, Burian P, Campbell M, Cho YM, de Montigny M, De Roeck A, Ellis JR, Sawy ME, Fairbairn M, Felea D, Frank M, Gould O, Hays J, Hirt AM, Ho DL-J, Hung PQ, Janecek J, Kalliokoski M, Korzenev A, Lacarrère DH, Leroy C, Levi G, Lionti A, Maulik A, Margiotta A, Mauri N, Mavromatos NE, Mermod P, Millward L, Mitsou VA, Ostrovskiy I, Ouimet P-P, Papavassiliou J, Parker B, Patrizii L, Păvălaş GE, Pinfold JL, Popa LA, Popa V, Pozzato M, Pospisil S, Rajantie A, de Austri RR, Sahnoun Z, Sakellariadou M, Santra A, Sarkar S, Semenoff G, Shaa A, Sirri G, Sliwa K, Soluk R, Spurio M, Staelens M, Suk M, Tenti M, Togo V, Tuszyn'ski JA, Upreti A, Vento V, Vives Oet al., 2022,

Search for magnetic monopoles produced via the Schwinger mechanism.

, Nature, Vol: 602, Pages: 63-67

Electrically charged particles can be created by the decay of strong enough electric fields, a phenomenon known as the Schwinger mechanism1. By electromagnetic duality, a sufficiently strong magnetic field would similarly produce magnetic monopoles, if they exist2. Magnetic monopoles are hypothetical fundamental particles that are predicted by several theories beyond the standard model3-7 but have never been experimentally detected. Searching for the existence of magnetic monopoles via the Schwinger mechanism has not yet been attempted, but it is advantageous, owing to the possibility of calculating its rate through semi-classical techniques without perturbation theory, as well as that the production of the magnetic monopoles should be enhanced by their finite size8,9 and strong coupling to photons2,10. Here we present a search for magnetic monopole production by the Schwinger mechanism in Pb-Pb heavy ion collisions at the Large Hadron Collider, producing the strongest known magnetic fields in the current Universe11. It was conducted by the MoEDAL experiment, whose trapping detectors were exposed to 0.235 per nanobarn, or approximately 1.8 × 109, of Pb-Pb collisions with 5.02-teraelectronvolt center-of-mass energy per collision in November 2018. A superconducting quantum interference device (SQUID) magnetometer scanned the trapping detectors of MoEDAL for the presence of magnetic charge, which would induce a persistent current in the SQUID. Magnetic monopoles with integer Dirac charges of 1, 2 and 3 and masses up to 75 gigaelectronvolts per speed of light squared were excluded by the analysis at the 95% confidence level. This provides a lower mass limit for finite-size magnetic monopoles from a collider search and greatly extends previous mass bounds.

Journal article

Arvanitakis AS, Hohm O, Hull C, Lekeu Vet al., 2022,

Homotopy transfer and effective field theory I: tree-level

, Fortschritte Der Physik/Progress of Physics, Vol: 70, Pages: 1-36, ISSN: 0015-8208

We use the dictionary between general field theories and strongly homotopyalgebras to provide an algebraic formulation of the procedure of integratingout of degrees of freedom in terms of homotopy transfer. This includes moregeneral effective theories in which some massive modes are kept while othermodes of a comparable mass scale are integrated out, as first explored by Senin the context of closed string field theory. We treatL∞-algebras both in termsof a nilpotent coderivation and, on the dual space, in terms of a nilpotentderivation (corresponding to the BRST charge of the field theory) and provideexplicit formulas for homotopy transfer. These are then shown to govern theintegrating out of degrees of freedom at tree level, while the generalization toloop level will be explored in a sequel to this paper.

Journal article

Erickson CW, Leung R, Stelle KS, 2022,

Taxonomy of brane gravity localisations

, The Journal of High Energy Physics, Vol: 2022, Pages: 1-63, ISSN: 1029-8479

Generating an effective theory of lower-dimensional gravity on a submanifold within an original higher-dimensional theory can be achieved even if the reduction space is non-compact. Localisation of gravity on such a lower-dimensional worldvolume can be interpreted in a number of ways. The first scenario, Type I, requires a mathematically consistent Kaluza-Klein style truncation down to a theory in the lower dimension, in which case solutions purely within that reduced theory exist. However, that situation is not a genuine localisation of gravity because all such solutions have higher-dimensional source extensions according to the Kaluza-Klein ansatz. Also, there is no meaningful notion of Newton’s constant for such Type I constructions.Types II and III admit coupling to genuinely localised sources in the higher-dimensional theory, with corresponding solutions involving full sets of higher-dimensional modes. Type II puts no specific boundary conditions near the worldvolume aside from regularity away from sources. In a case where the wave equation separated in the non-compact space transverse to the worldvolume admits a normalisable zero mode, the Type III scenario requires boundary conditions near the worldvolume that permit the inclusion of that zero mode in mode expansions for gravitational wave fluctuations or potentials. In such a case, an effective theory of lower-dimensional gravity can emerge at sufficiently large worldvolume distance scales.This taxonomy of brane gravity localisations is developed in detail for linearised perturbations about a background incorporating the vacuum solution of Salam-Sezgin theory when embedded into ten-dimensional supergravity with a hyperbolic non-compact transverse space. Interpretations of the Newton constant for the corresponding Type III localisation are then analysed.

Journal article

Beccaria M, Tseytlin AA, 2022,

1/N expansion of circular Wilson loop in N = 2 superconformal SU(N) x SU(N) quiver (vol 265, JHEP04, 2021)

, The Journal of High Energy Physics, Vol: 115, ISSN: 1029-8479

Journal article

Ferrero P, Gauntlett JP, Sparks J, 2022,

Supersymmetric spindles

, The Journal of High Energy Physics, Vol: 102, ISSN: 1029-8479

In the context of holography, we analyse aspects of supersymmetric geometries based on two-dimensional orbifolds known as spindles. By analysing spinc spinors on a spindle with an azimuthal rotation symmetry we show that under rather general conditions there are just two possibilities, called the ‘twist’ and the ‘anti-twist’, which are determined by the quantized magnetic flux through the spindle. A special case of the twist is the standard topological twist which is associated with constant and chiral spinors. We construct solutions of D = 5 and D = 4 STU gauged supergravity theories that are dual to D3-branes and M2-branes wrapping spindles, respectively, which realize both the anti-twist, as seen before, but also the twist. For the wrapped D3-brane solutions we reproduce the central charge of the gravity solution from the dual field theory by analysing the anomaly polynomial of N = 4 SYM theory. We also discuss M5-branes wrapped on spindles both from a gravity and a field theory point of view.

Journal article

Renzini A, Romano JD, Contaldi CR, Cornish NJet al., 2022,

Comparison of maximum-likelihood mapping methods for gravitational-wave backgrounds

, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 105, Pages: 1-12, ISSN: 1550-2368

Detection of a stochastic background of gravitational waves is likely to occur in the next few years. Beyond searches for the isotropic component of a stochastic gravitational-wave background, there have been various mapping methods proposed to target anisotropic backgrounds. Some of these methods have been applied to data taken by the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo. Specifically, these directional searches have focused on mapping the intensity of the signal on the sky via maximum-likelihood solutions. We compare this intensity mapping approach to a previously proposed, but never employed, amplitude-phase mapping method to understand whether this latter approach may be employed in future searches. We build up our understanding of the differences between these two approaches by analyzing simple toy models of time-stream data, and we run mock-data mapping tests for the two methods. We find that the amplitude-phase method is only applicable to the case of a background which is phase coherent on large scales or, at the very least, has an intrinsic coherence scale that is larger than the resolution of the detector. Otherwise, the amplitude-phase mapping method leads to an overall loss of information, with respect to both phase and amplitude. Since we do not expect these phase-coherent properties to hold for any of the gravitational-wave background signals we hope to detect in the near future, we conclude that intensity mapping is the preferred method for such backgrounds.

Journal article

Beccaria M, Giombi S, Tseytlin AA, 2022,

Higher order RG flow on the Wilson line in N=4 SYM

, The Journal of High Energy Physics, Vol: 2022, Pages: 1-28, ISSN: 1029-8479

Extending earlier work, we find the two-loop term in the beta-function for the scalar coupling ζ in a generalized Wilson loop operator of the N = 4 SYM theory, working in the planar weak-coupling expansion. The beta-function for ζ has fixed points at ζ = ±1 and ζ = 0, corresponding respectively to the supersymmetric Wilson-Maldacena loop and to the standard Wilson loop without scalar coupling. As a consequence of our result for the beta-function, we obtain a prediction for the two-loop term in the anomalous dimension of the scalar field inserted on the standard Wilson loop. We also find a subset of higher-loop contributions (with highest powers of ζ at each order in ‘t Hooft coupling λ) coming from the scalar ladder graphs determining the corresponding terms in the five-loop beta-function. We discuss the related structure of the circular Wilson loop expectation value commenting, in particular, on consistency with a 1d defect version of the F-theorem. We also compute (to two loops in the planar ladder model approximation) the two-point correlators of scalars inserted on the Wilson line

Journal article

de Rham C, Heisenberg L, Kumar A, Zosso Jet al., 2022,

Quantum stability of a new Proca theory

, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 105, Pages: 1-8, ISSN: 1550-2368

The construction of general derivative self-interactions for a massive Proca field relies on the well-known condition for constrained systems of having a degenerate Hessian. The nature of the existing constraints algebra will distinguish among different classes of interactions. Proca-Nuevo interactions enjoy a nontrivial constraint by mixing terms of various order whereas generalized Proca interactions satisfy the degeneracy condition order by order for each individual Lagrangian. In both cases the vector field propagates at most 3 degrees of freedom. It has been shown that the scattering amplitudes of Proca-Nuevo arising at the tree level always differ from those of the generalized Proca, implying their genuinely different nature and a lack of relation by local field redefinitions. In this work, we show the quantum stability of the Proca-Nuevo theory below a specific UV cutoff. Although Proca-Nuevo and generalized Proca are different inherently in their classical structure, both have the same high energy behavior when quantum corrections are taken into account. The arising counterterms have the exact same structure and scaling. This might indicate that whatever UV completion they may come from, we expect it to be of similar nature.

Journal article

Seoane PA, Sedda MA, Babak S, Berry CPL, Berti E, Bertone G, Blas D, Bogdanovic T, Bonetti M, Breivik K, Brito R, Caldwell R, Capelo PR, Caprini C, Cardoso V, Carson Z, Chen H-Y, Chua AJK, Dvorkin I, Haiman Z, Heisenberg L, Isi M, Karnesis N, Kavanagh BJ, Littenberg TB, Mangiagli A, Marcoccia P, Maselli A, Nardini G, Pani P, Peloso M, Pieroni M, Ricciardone A, Sesana A, Tamanini N, Toubiana A, Valiante R, Vretinaris S, Weir DJ, Yagi K, Zimmerman Aet al., 2022,

The effect of mission duration on LISA science objectives

, GENERAL RELATIVITY AND GRAVITATION, Vol: 54, ISSN: 0001-7701

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Citations: 20

Journal article

Bugden M, Hulik O, Valach F, Waldram Det al., 2022,

Exceptional algebroids and Type IIB superstrings

, Fortschritte Der Physik/Progress of Physics, Vol: 70, Pages: 1-8, ISSN: 0015-8208

In this note we study exceptional algebroids, focusing on their relation to type IIB superstring theory. We show that a IIB-exact exceptional algebroid (corresponding to the group urn:x-wiley:00158208:media:prop202100104:prop202100104-math-0001, for urn:x-wiley:00158208:media:prop202100104:prop202100104-math-0002) locally has a standard form given by the exceptional tangent bundle. We derive possible twists, given by a flat urn:x-wiley:00158208:media:prop202100104:prop202100104-math-0003-connection, a covariantly closed pair of 3-forms, and a 5-form, and comment on their physical interpretation. Using this analysis we reduce the search for Leibniz parallelisable spaces, and hence maximally supersymmetric consistent truncations, to a simple algebraic problem. We show that the exceptional algebroid perspective also gives a simple description of Poisson–Lie U-duality without spectators and hence of generalised Yang–Baxter deformations.

Journal article

Avetisyan Z, Evnin O, Mkrtchyan K, 2021,

Democratic Lagrangians for Nonlinear Electrodynamics

, PHYSICAL REVIEW LETTERS, Vol: 127, ISSN: 0031-9007

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Journal article

Alexandre B, Magueijo J, 2021,

Semiclassical limit problems with concurrent use of several clocks in quantum cosmology

, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 104, ISSN: 1550-2368

We revisit a recent proposal for a definition of time in quantum cosmology, to investigate the effects of having more than one possible type of clock “at the same time.” We use as a test tube an extension of Einstein gravity with a massless scalar field in which the gravitational coupling GN is only a constant on-shell, mimicking the procedure for Λ in unimodular gravity. Hence we have two “simultaneous” clocks in the theory: a scalar field clock, and the conjugate of GN. We find that attempts to use two coherent clocks concurrently are disastrous for recovering the classical limit. The Heisenberg relations, instead of being saturated, are always realized abundantly above their bound, with strong quantum effects expected at least in parts of the trajectory. Semiclassical states always result from situations where we effectively impose a single clock, either by making the other clock a failed clock (i.e., by choosing a state where its conjugate constant is infinitely sharp) or by choosing a basis of constants where all clocks but one are redundant; i.e., motion or change in phase space does not occur with the passing of their “times.” We show how this conclusion generalizes to fluids with any equation of state. It also applies to systems where “subclocks” of the same type could be used, for example, in mixtures of different fluids with the same equation of state.https://journals.aps.org/prd/abstract/10.1103/PhysRevD.104.124069

Journal article

Borsten L, Duff MJ, Nagy S, 2021,

Odd dimensional analogue of the Euler characteristic

, The Journal of High Energy Physics, Vol: 2021, ISSN: 1029-8479

When compact manifolds X and Y are both even dimensional, their Euler characteristics obey the Künneth formula χ(X × Y) = χ(X)χ(Y). In terms of the Betti numbers bp(X), χ(X) = Σp(−1)pbp(X), implying that χ(X) = 0 when X is odd dimensional. We seek a linear combination of Betti numbers, called ρ, that obeys an analogous formula ρ(X × Y) = χ(X)ρ(Y) when Y is odd dimensional. The unique solution is ρ(Y) = − Σp(−1)ppbp(Y). Physical applications include: (1) ρ → (−1)mρ under a generalized mirror map in d = 2m + 1 dimensions, in analogy with χ → (−1)mχ in d = 2m; (2) ρ appears naturally in compactifications of M-theory. For example, the 4-dimensional Weyl anomaly for M-theory on X4 × Y7 is given by χ(X4)ρ(Y7) = ρ(X4 × Y7) and hence vanishes when Y7 is self-mirror. Since, in particular, ρ(Y × S1) = χ(Y), this is consistent with the corresponding anomaly for Type IIA on X4 × Y6, given by χ(X4)χ(Y6) = χ(X4 × Y6), which vanishes when Y6 is self-mirror; (3) In the partition function of p-form gauge fields, ρ appears in odd dimensions as χ does in even.

Journal article

Alday LF, Chester SM, Hansen T, 2021,

Modular invariant holographic correlators for $$ \mathcal{N} $$ = 4 SYM with general gauge group

, Journal of High Energy Physics, Vol: 2021

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We study the stress tensor four-point function for <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \mathcal{N} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>N</mml:mi> </mml:math></jats:alternatives></jats:inline-formula> = 4 SYM with gauge group <jats:italic>G</jats:italic> = SU(<jats:italic>N</jats:italic>), SO(2<jats:italic>N</jats:italic> + 1), SO(2<jats:italic>N</jats:italic>) or USp(2<jats:italic>N</jats:italic>) at large <jats:italic>N</jats:italic> . When <jats:italic>G</jats:italic> = SU(<jats:italic>N</jats:italic>), the theory is dual to type IIB string theory on <jats:italic>AdS</jats:italic><jats:sub>5</jats:sub><jats:italic>× S</jats:italic><jats:sup>5</jats:sup> with complexified string coupling <jats:italic>τ</jats:italic><jats:sub><jats:italic>s</jats:italic></jats:sub>, while for the other cases it is dual to the orbifold theory on <jats:italic>AdS</jats:italic><jats:sub>5</jats:sub><jats:italic>× S</jats:italic><jats:sup>5</jats:sup><jats:italic>/</jats:italic>ℤ<jats:sub>2</jats:sub>. In all cases we use the analytic bootstrap and constraints from localization to compute 1-loop and higher derivative tree level corrections to the leading supergravity approximation of the correlator. We give perturbative evidence that the localization constraint in the large <jats:italic>N</jats:italic> and finite complexified coupling <jats:italic>τ</jats:italic> limit can be written for each <jats:italic>G</j

Journal article

Gledhill K, Hanany A, 2021,