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  • Journal article
    Dowker F, Sorkin RD, 2020,

    Symmetry-breaking and zero-one laws

    , Classical and Quantum Gravity, Vol: 37, ISSN: 0264-9381

    We offer further evidence that discreteness of the sort inherent in a causal set cannot, in and of itself, serve to break Poincaré invariance. In particular we prove that a Poisson sprinkling of Minkowski spacetime cannot endow spacetime with a distinguished spatial or temporal orientation, or with a distinguished lattice of spacetime points, or with a distinguished lattice of timelike directions (corresponding respectively to breakings of reflection-invariance, translation-invariance, and Lorentz invariance). Along the way we provide a proof from first principles of the zero-one law on which our new arguments are based.
  • Journal article
    Contaldi CR, Pieroni M, Renzini A, Cusin G, Karnesis N, Peloso M, Ricciardone A, Tasinato Get al., 2020,

    Maximum likelihood map making with the Laser Interferometer Space Antenna

    , Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 102, Pages: 043502 – 1-043502 – 13, ISSN: 1550-2368

    Given the recent advances in gravitational-wave detection technologies, the detection and characterization of gravitational-wave backgrounds (GWBs) with the Laser Interferometer Space Antenna (LISA) is a real possibility. To assess the abilities of the LISA satellite network to reconstruct anisotropies of different angular scales and in different directions on the sky, we develop a map-maker based on an optimal quadratic estimator. The resulting maps are maximum likelihood representations of the GWB intensity on the sky integrated over a broad range of frequencies. We test the algorithm by reconstructing known input maps with different input distributions and over different frequency ranges. We find that, in an optimal scenario of well understood noise and high frequency, high SNR signals, the maximum scales LISA may probe are ℓmax≲15. The map-maker also allows to test the directional dependence of LISA noise, providing insight on the directional sky sensitivity we may expect.
  • Journal article
    Duff MJ, 2020,

    Weyl, Pontryagin, Euler, Eguchi and Freund

    , Journal of Physics A: Mathematical and Theoretical, Vol: 53, ISSN: 1751-8113

    In a September 1976 PRL Eguchi and Freund considered two topological invariants: the Pontryagin number $P\sim \int {\mathrm{d}}^{4}x\sqrt{g}{R}^{{\ast}}R$ and the Euler number $\chi \sim \int {\mathrm{d}}^{4}x\sqrt{g}{R}^{{\ast}}{R}^{{\ast}}$ and posed the question: to what anomalies do they contribute? They found that P appears in the integrated divergence of the axial fermion number current, thus providing a novel topological interpretation of the anomaly found by Kimura in 1969 and Delbourgo and Salam in 1972. However, they found no analogous role for χ. This provoked my interest and, drawing on my April 1976 paper with Deser and Isham on gravitational Weyl anomalies, I was able to show that for conformal field theories the trace of the stress tensor depends on just two constants: ${g}^{\mu \nu }\langle {T}_{\mu \nu }\rangle =\frac{1}{{\left(4\pi \right)}^{2}}\left(cF-aG\right)$ where F is the square of the Weyl tensor and $\int {\mathrm{d}}^{4}x\sqrt{g}G/{\left(4\pi \right)}^{2}$ is the Euler number. For free CFTs with N s massless fields of spin s $720c=6{N}_{0}+18{N}_{1/2}+72{N}_{1}720a=2{N}_{0}+11{N}_{1/2}+124{N}_{1}$.
  • Journal article
    Bourget A, Grimminger JF, Hanany A, Sperling M, Zhong Zet al., 2020,

    Magnetic quivers from brane webs with O5 planes

    , The Journal of High Energy Physics, Vol: 2020, Pages: 1-82, ISSN: 1029-8479

    Magnetic quivers have led to significant progress in the understanding of gauge theories with 8 supercharges at UV fixed points. For a given low-energy gauge theory realised via a Type II brane construction, there exist magnetic quivers for the Higgs branches at finite and infinite gauge coupling. Comparing these moduli spaces allows one to study the non-perturbative effects when transitioning to the fixed point. For 5d N = 1 SQCD, 5-brane webs have been an important tool for deriving magnetic quivers. In this work, the emphasis is placed on 5-brane webs with orientifold 5-planes which give rise to 5d theories with orthogonal or symplectic gauge groups. For this set-up, the magnetic quiver prescription is derived and contrasted against a unitary magnetic quiver description extracted from an O7− construction. Further validation is achieved by a derivation of the associated Hasse diagrams. An important class of families considered are the orthogonal exceptional En families (−∞ < n ≤ 8), realised as infinite coupling Higgs branches of Sp(k) gauge theories with fundamental matter. In particular, the moduli spaces are realised by a novel type of magnetic quivers, called unitary-orthosymplectic quivers.
  • Journal article
    de Rham C, Francfort J, Zhang J, 2020,

    Black hole gravitational waves in the effective field theory of gravity

    , Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 102, Pages: 024079 – 1-024079 – 14, ISSN: 1550-2368

    We investigate the propagation of gravitational waves on a black hole background within the low-energy effective field theory of gravity, where effects from heavy fields are captured by higher-dimensional curvature operators. Depending on the spin of the particles integrated out, the speed of gravitational waves at low energy can be either superluminal or subluminal as compared to the causal structure observed by other species. Interestingly, however, gravitational waves are always exactly luminal at the black hole horizon, implying that the horizon is identically defined for all species. We further compute the corrections on quasinormal frequencies caused by the higher-dimensional curvature operators and highlight the corrections arising from the low-energy effective field.
  • Journal article
    Drukker N, Giombi S, Tseytlin AA, Zhou Xet al., 2020,

    Defect CFT in the 6d (2,0) theory from M2 brane dynamics in AdS7×S4

    , The Journal of High Energy Physics, Vol: 2020, ISSN: 1029-8479

    Surface operators in the 6d (2,0) theory at large $N$ have a holographicdescription in terms of M2 branes probing the AdS$_7 \times S^4$ M-theorybackground. The most symmetric, 1/2-BPS, operator is defined over a planar orspherical surface, and it preserves a 2d superconformal group. This includes,in particular, an $SO(2,2)$ subgroup of 2d conformal transformations, so thatthe surface operator may be viewed as a conformal defect in the 6d theory. Thedual M2 brane has an AdS$_3$ induced geometry, reflecting the 2d conformalsymmetry. Here we use the holographic description to extract the defect CFTdata associated to the surface operator. The spectrum of transversefluctuations of the M2 brane is found to be in one-to-one correspondence with aprotected multiplet of operator insertions on the surface, which includes thedisplacement operator. We compute the one-loop determinants of fluctuations ofthe M2 brane, and extract the conformal anomaly coefficient of the sphericalsurface to order $N^0$. We also briefly discuss the RG flow from thenon-supersymmetric to the 1/2-BPS defect operator, and its consistency with a"$b$-theorem" for the defect CFT. Starting with the M2 brane action, we thenuse AdS$_3$ Witten diagrams to compute the 4-point functions of the elementarybosonic insertions on the surface operator, and extract some of the defect CFTdata from the OPE. The 4-point function is shown to satisfy superconformal Wardidentities, and we discuss a related subsector of "twisted" scalar insertions,whose correlation functions are constrained by the residual superconformalsymmetry.
  • Journal article
    Donos A, Gauntlett JP, Pantelidou C, 2020,

    Holographic Abrikosov lattices

    , The Journal of High Energy Physics, Vol: 2020, Pages: 1-26, ISSN: 1029-8479

    We study black hole solutions of D = 4 Einstein-Maxwell theory coupled to a charged scalar field that are holographically dual to a d = 3 conformal field theory with a non-vanishing chemical potential and constant magnetic field. We numerically construct black hole solutions that are dual to a superfluid phase with a periodic lattice of vortices. For the specific model we investigate, we find that the thermodynamically preferred con- figuration is given by a triangular lattice and moreover the vortices are associated with the lowest Landau level. We also construct black holes describing a lattice of vortices associated with the next to lowest Landau level and while these are not thermodynamically preferred they exhibit some interesting features that could be realised for other holographic models.
  • Journal article
    Hull C, Marcus E, Stemerdink K, Vandoren Set al., 2020,

    Black holes in string theory with duality twists

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Journal article
    de Rham C, 2020,

    Rethinking gravity

    , New Scientist, Vol: 247, Pages: 31-34, ISSN: 0262-4079

    Theoretical physicist Claudia de Rham has shown that gravity itself could have a mass – giving us a whole new picture of this fundamental force
  • Journal article
    Halliwell JJ, Mawby C, 2020,

    Conditions for macrorealism for systems described by many-valued variables

    , Physical Review A: Atomic, Molecular and Optical Physics, Vol: 102, Pages: 012209 – 1-012209 – 15, ISSN: 1050-2947

    Macrorealism (MR) is the view that a system evolving in time possesses definite properties independent of past or future measurements and is traditionally tested for systems described at each time by a single dichotomic variable Q. A number of necessary and sufficient conditions for macrorealism have been derived for a dichotomic variable using sets of Leggett-Garg (LG) inequalities, or the stronger no signaling in time (NSIT) conditions, or a combination thereof. Here we extend this framework by establishing necessary and sufficient conditions for macrorealism for measurements made at two and three times for systems described by variables taking three or more values at each time. Our results include a generalization of Fine's theorem to many-valued variables for measurements at three pairs of times and we derive the corresponding complete set of LG inequalities. We find that LG inequalities and NSIT conditions for many-valued variables do not enjoy the simple hierarchical relationship exhibited by the dichotomic case. This sheds light on some recent experiments on three-level systems which exhibit a LG inequality violation even though certain NSIT conditions are satisfied. Under measurements of dichotomic variables using the Lüders projection rule the three-time LG inequalities cannot be violated beyond the Lüders bound (which coincides numerically with the Tsirelson bound obeyed by correlators in Bell experiments), but this bound can be violated in LG tests using degeneracy-breaking (von Neumann) measurements. We identify precisely which MR conditions are violated under these circumstances.
  • Journal article
    Chester SM, Kalloor RR, Sharon A, 2020,

    3d $$ \mathcal{N} $$ = 4 OPE coefficients from Fermi gas

    , Journal of High Energy Physics, Vol: 2020

    <jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>The partition function of a 3d <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 gauge theory with rank <jats:italic>N</jats:italic> can be computed using supersymmetric localization in terms of a matrix model, which often can be formulated as an ideal Fermi gas with a non-trivial one-particle Hamiltonian. We show how OPE coefficients of protected operators correspond in this formalism to averages of <jats:italic>n</jats:italic>-body operators in the Fermi gas, which can be computed to all orders in 1<jats:italic>/N</jats:italic> using the WKB expansion. We use this formalism to compute OPE coefficients in the U(<jats:italic>N</jats:italic>)<jats:sub><jats:italic>k</jats:italic></jats:sub><jats:italic>×</jats:italic> U(<jats:italic>N</jats:italic>)<jats:sub><jats:italic>−k</jats:italic></jats:sub> ABJM theory as well as the U(<jats:italic>N</jats:italic> ) theory with one adjoint and <jats:italic>N</jats:italic><jats:sub><jats:italic>f</jats:italic></jats:sub> fundamental hypermultiplets, both of which have weakly coupled M-theory duals in the large <jats:italic>N</jats:italic> and finite <jats:italic>k</jats:italic> or <jats:italic>N</jats:italic><jats:sub><jats:italic>f</jats:italic></jats:sub> regimes. For ABJM we reproduce known results, while for the <jats:italic>N</jats:italic><jats:sub><jats:italic>f</jats:italic>&l
  • Journal article
    Evans TS, Calmon L, Vasiliauskaite V, 2020,

    Longest path in the price model

    , Scientific Reports, Vol: 10, Pages: 1-9, ISSN: 2045-2322

    The Price model, the directed version of the Barab\'{a}si-Albert model,produces a growing directed acyclic graph. We look at variants of the model inwhich directed edges are added to the new vertex in one of two ways: usingcumulative advantage (preferential attachment) choosing vertices in proportionto their degree, or with random attachment in which vertices are chosenuniformly at random. In such networks, the longest path is well defined and insome cases is known to be a better approximation to geodesics than the shortestpath. We define a reverse greedy path and show both analytically andnumerically that this scales with the logarithm of the size of the network witha coefficient given by the number of edges added using random attachment. Thisis a lower bound on the length of the longest path to any given vertex and weshow numerically that the longest path also scales with the logarithm of thesize of the network but with a larger coefficient that has some weak dependenceon the parameters of the model.
  • Journal article
    Chester SM, Landry W, Liu J, Poland D, Simmons-Duffin D, Su N, Vichi Aet al., 2020,

    Carving out OPE space and precise O(2) model critical exponents

    , Journal of High Energy Physics, Vol: 2020

    <jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>We develop new tools for isolating CFTs using the numerical bootstrap. A “cutting surface” algorithm for scanning OPE coefficients makes it possible to find islands in high-dimensional spaces. Together with recent progress in large-scale semidefinite programming, this enables bootstrap studies of much larger systems of correlation functions than was previously practical. We apply these methods to correlation functions of charge-0, 1, and 2 scalars in the 3d O(2) model, computing new precise values for scaling dimensions and OPE coefficients in this theory. Our new determinations of scaling dimensions are consistent with and improve upon existing Monte Carlo simulations, sharpening the existing decades-old 8<jats:italic>σ</jats:italic> discrepancy between theory and experiment.</jats:p>
  • Journal article
    Alonso D, Contaldi CR, Cusin G, Ferreira PG, Renzini Aet al., 2020,

    Noise angular power spectrum of gravitational wave background experiments

    , Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 101, Pages: 124048 – 1-124048 – 17, ISSN: 1550-2368

    We construct a model for the angular power spectrum of the instrumental noise in interferometer networks mapping gravitational wave backgrounds (GWBs) as a function of detector noise properties, network configuration, and scan strategy. We use the model to calculate the noise power spectrum for current and future ground-based experiments, as well as for planned space missions. We present our results in a language similar to that used in cosmic microwave background and intensity mapping experiments, and connect the formalism with the sensitivity curves that are common lore in GWB analyses.
  • Journal article
    Fredenhagen S, Krueger O, Mkrtchyan K, 2020,

    Restrictions for <i>n</i>-point vertices in higher-spin theories

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Journal article
    Falkenberg M, Lee J-H, Amano S-I, Ogawa K-I, Yano K, Miyake Y, Evans TS, Christensen Ket al., 2020,

    Identifying time dependence in network growth

    , Physical Review & Research International, Vol: 2, Pages: 023352 – 1-023352 – 17, ISSN: 2231-1815

    Identifying power-law scaling in real networks—indicative of preferential attachment—has proved controversial. Critics argue that measuring the temporal evolution of a network directly is better than measuring the degree distribution when looking for preferential attachment. However, many of the established methods do not account for any potential time dependence in the attachment kernels of growing networks, or methods assume that node degree is the key observable determining network evolution. In this paper, we argue that these assumptions may lead to misleading conclusions about the evolution of growing networks. We illustrate this by introducing a simple adaptation of the Barabási-Albert model, the “k2 model,” where new nodes attach to nodes in the existing network in proportion to the number of nodes one or two steps from the target node. The k2 model results in time dependent degree distributions and attachment kernels, despite initially appearing to grow as linear preferential attachment, and without the need to include explicit time dependence in key network parameters (such as the average out-degree). We show that similar effects are seen in several real world networks where constant network growth rules do not describe their evolution. This implies that measurements of specific degree distributions in real networks are likely to change over time.
  • Journal article
    Tolley AJ, 2020,

    TT(T)over-bar deformations, massive gravity and non-critical strings

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
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    • Citations: 64
  • Journal article
    Ciacci A, Falkenberg M, Manani KA, Evans TS, Peters NS, Christensen Ket al., 2020,

    Understanding the transition from paroxysmal to persistent atrial fibrillation

    , Physical Review Research, Vol: 2, Pages: 1-23, ISSN: 2643-1564

    Atrial fibrillation (AF) is the most common cardiac arrhytmia, characterisedby the chaotic motion of electrical wavefronts in the atria. In clinicalpractice, AF is classified under two primary categories: paroxysmal AF, shortintermittent episodes separated by periods of normal electrical activity, andpersistent AF, longer uninterrupted episodes of chaotic electrical activity.However, the precise reasons why AF in a given patient is paroxysmal orpersistent is poorly understood. Recently, we have introduced the percolationbased Christensen-Manani-Peters (CMP) model of AF which naturally exhibits bothparoxysmal and persistent AF, but precisely how these differences emerge in themodel is unclear. In this paper, we dissect the CMP model to identify the causeof these different AF classifications. Starting from a mean-field model wherewe describe AF as a simple birth-death process, we add layers of complexity tothe model and show that persistent AF arises from the formation of temporallystable structural re-entrant circuits that form from the interaction ofwavefront collisions during paroxysmal AF. These results are compatible withrecent findings suggesting that the formation of re-entrant drivers in fibroticborder zones perpetuates persistent AF.
  • Working paper
    Contaldi CR, 2020,

    COVID-19: nowcasting reproduction factors using biased case testing data

    , Publisher: arXiv

    Timely estimation of the current value for COVID-19 reproduction factor $R$has become a key aim of efforts to inform management strategies. $R$ is animportant metric used by policy-makers in setting mitigation levels and is alsoimportant for accurate modelling of epidemic progression. This brief paperintroduces a method for estimating $R$ from biased case testing data. Usingtesting data, rather than hospitalisation or death data, provides a muchearlier metric along the symptomatic progression scale. This can be hugelyimportant when fighting the exponential nature of an epidemic. We develop apractical estimator and apply it to Scottish case testing data to infer acurrent (20 May 2020) $R$ value of $0.74$ with $95\%$ confidence interval$[0.48 - 0.86]$.
  • Journal article
    Bruce R, dEnterria D, de Roeck A, Drewes M, Farrar GR, Giammanco A, Gould O, Hajer J, Harland-Lang L, Heisig J, Jowett JM, Kabana S, Krintiras GK, Korsmeier M, Lucente M, Milhano G, Mukherjee S, Niedziela J, Okorokov VA, Rajantie A, Schaumann Met al., 2020,

    New physics searches with heavy-ion collisions at the CERN Large Hadron Collider

    , Journal of Physics G: Nuclear and Particle Physics, Vol: 47, Pages: 1-20, ISSN: 0954-3899

    This document summarises proposed searches for new physics accessible in the heavy-ion mode at the CERN Large Hadron Collider (LHC), both through hadronic and ultraperipheral γγ interactions, and that have a competitive or, even, unique discovery potential compared to standard proton–proton collision studies. Illustrative examples include searches for new particles—such as axion-like pseudoscalars, radions, magnetic monopoles, new long-lived particles, dark photons, and sexaquarks as dark matter candidates—as well as new interactions, such as nonlinear or non-commutative QED extensions. We argue that such interesting possibilities constitute a well-justified scientific motivation, complementing standard quark-gluon-plasma physics studies, to continue running with ions at the LHC after the Run-4, i.e. beyond 2030, including light and intermediate-mass ion species, accumulating nucleon–nucleon integrated luminosities in the accessible fb−1 range per month.
  • Journal article
    Grall T, Jazayeri S, Pajer E, 2020,

    Symmetric scalars

    , Journal of Cosmology and Astroparticle Physics, Vol: 2020, Pages: 031-031
  • Journal article
    Osherson B, Filippini JP, Fu J, Gramillano R, Gualtieri R, Shaw EC, Ade PAR, Amiri M, Benton SJ, Bock JJ, Bond JR, Bryan SA, Chiang HC, Contaldi CR, Dore O, Fraisse AA, Gambrel AE, Gandilo NN, Gudmundsson JE, Halpern M, Hartley JW, Hasselfield M, Hilton G, Holmes W, Hristov VV, Irwin KD, Jones WC, Kermish ZD, Mason P, Megerian K, Moncelsi L, Morford TA, Nagy JM, Netterfield CB, Padilla IL, Rahlin AS, Reintsema C, Ruhl JE, Runyan MC, Shariff JA, Soler JD, Trangsrud A, Tucker C, Tucker RS, Turner AD, Weber AC, Wiebe D, Young EYet al., 2020,

    Particle response of antenna-coupled TES arrays: results from SPIDER and the laboratory

    , Journal of Low Temperature Physics, Vol: 199, Pages: 1127-1136, ISSN: 0022-2291

    Future mm-wave and sub-mm space missions will employ large arrays of multiplexed transition-edge-sensor (TES) bolometers. Such instruments must contend with the high flux of cosmic rays beyond our atmosphere that induce ‘glitches’ in bolometer data, which posed a challenge to data analysis from the Planck bolometers. Future instruments will face the additional challenges of shared substrate wafers and multiplexed readout wiring. In this work, we explore the susceptibility of modern TES arrays to the cosmic ray environment of space using two data sets: the 2015 long-duration balloon flight of the SPIDER cosmic microwave background polarimeter, and a laboratory exposure of SPIDER flight hardware to radioactive sources. We find manageable glitch rates and short glitch durations, leading to minimal effect on SPIDER analysis. We constrain energy propagation within the substrate through a study of multi-detector coincidences and give a preliminary look at pulse shapes in laboratory data.
  • Journal article
    Sirks EL, Clark P, Massey RJ, Benton SJ, Brown AM, Damaren CJ, Eifler T, Fraisse AA, Frenk C, Funk M, Galloway MN, Gill A, Hartley JW, Holder B, Huff EM, Jauzac M, Jones WC, Lagattuta D, Leung JS-Y, Li L, Luu TVT, McCleary J, Nagy JM, Netterfield CB, Redmond S, Rhodes JD, Romualdez LJ, Schmoll J, Shaaban MM, Tam Set al., 2020,

    Download by parachute: retrieval of assets from high altitude balloons

    , JOURNAL OF INSTRUMENTATION, Vol: 15, ISSN: 1748-0221
  • Journal article
    Beccaria M, Jiang H, Tseytlin AA, 2020,

    Boundary correlators in WZW model on AdS2

    , The Journal of High Energy Physics, Vol: 2020, Pages: 1-37, ISSN: 1029-8479

    Boundary correlators of elementary fields in some 2d conformal field theories defined on AdS2 have a particularly simple structure. For example, the correlators of the Liouville scalar happen to be the same as the correlators of the chiral component of the stress tensor on a plane restricted to the real line. Here we show that an analogous relation is true also in the WZW model: boundary correlators of the WZW scalars have the same structure as the correlators of chiral Kac-Moody currents. This is checked at the level of the tree and one-loop Witten diagrams in AdS2. We also compute some tree-level correlators in a generic σ-model defined on AdS2 and show that they simplify only in the WZW case where an extra Kac-Moody symmetry appears. In particular, the terms in 4- point correlators having logarithmic dependence on 1d cross-ratio cancel only at the WZW point. One motivation behind this work is to learn how to compute AdS2 loop corrections in 2d models with derivative interactions related to the study of correlators of operators on Wilson loops in string theory in AdS.
  • Journal article
    Tseytlin AA, 2020,

    Comments on open string with 'massive' boundary term

    , Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol: 476, Pages: 1-9, ISSN: 1364-5021

    We discuss possible definition of open string path integral in the presence of additional boundary couplings corresponding to the presence of masses at the ends of the string. These couplings are not conformally invariant implying that as in a non-critical string case one is to integrate over the one-dimensional metric or reparametrizations of the boundary. We compute the partition function on the disc in the presence of an additional constant gauge field background and comment on the structure of the corresponding scattering amplitudes.
  • Journal article
    Dowker F, Imambaccus N, Owens A, Sorkin R, Zalel Set al., 2020,

    A manifestly covariant framework for causal set dynamics

    , Classical and Quantum Gravity, Vol: 37, Pages: 085003-085003, ISSN: 0264-9381

    We propose a manifestly covariant framework for causal set dynamics. The framework is based on a structure, dubbed covtree, which is a partial order on certain sets of finite, unlabeled causal sets. We show that every infinite path in covtree corresponds to at least one infinite, unlabeled causal set. We show that transition probabilities for a classical random walk on covtree induce a classical measure on the -algebra generated by the stem sets.
  • Journal article
    Binder DJ, Chester SM, Pufu SS, 2020,

    Absence of D4R4 in M-theory from ABJM

    , Journal of High Energy Physics, Vol: 2020

    <jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>Supersymmetry allows a <jats:italic>D</jats:italic> <jats:sup>4</jats:sup> <jats:italic>R</jats:italic> <jats:sup>4</jats:sup> interaction in M-theory, but such an interaction is inconsistent with string theory dualities and so is known to be absent. We provide a novel proof of the absence of the <jats:italic>D</jats:italic> <jats:sup>4</jats:sup> <jats:italic>R</jats:italic> <jats:sup>4</jats:sup> M-theory interaction by calculating 4-point scattering amplitudes of 11d supergravitons from ABJM theory. This calculation extends a previous calculation performed to the order corresponding to the <jats:italic>R</jats:italic> <jats:sup>4</jats:sup> interaction. The new ingre- dient in this extension is the interpretation of the fourth derivative of the mass deformed <jats:italic>S</jats:italic> <jats:sup>3</jats:sup> partition function of ABJM theory, which can be determined using supersymmetric localization, as a constraint on the Mellin amplitude associated with the stress tensor mul- tiplet 4-point function. As part of this computation, we relate the 4-point function of the superconformal primary of the stress tensor multiplet of any 3d <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> = 8 SCFT to some of the 4-point functions of its superconformal descendants. We also provide a concise formula f
  • Journal article
    Chester SM, 2020,

    Genus-2 holographic correlator on AdS5 × S5 from localization

    , Journal of High Energy Physics, Vol: 2020, ISSN: 1029-8479

    <jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>We consider the four-point function of the stress tensor multiplet superprimary in <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 super-Yang-Mills (SYM) with gauge group SU(<jats:italic>N</jats:italic> ) in the large <jats:italic>N</jats:italic> and large ’t Hooft coupling <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \lambda \equiv {g}_{\mathrm{YM}}^2N $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>λ</mml:mi> <mml:mo>≡</mml:mo> <mml:msubsup> <mml:mi>g</mml:mi> <mml:mi>YM</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> <mml:mi>N</mml:mi> </mml:math> </jats:alternatives> </jats:inline-formula> limit, which is holographically dual to the genus expansion of IIB string theory on AdS<jats:sub>5</jats:sub> <jats:italic>× S</jats:italic> <jats:sup>5</jats:sup>. In [1] it was shown that the integral of this correlator is related to derivatives of the mass deformed <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \mathcal{N} $$</jats:tex-math>
  • Journal article
    Ho DL-J, Rajantie A, 2020,

    Classical production of 't Hooft-Polyakov monopoles from magnetic fields

    , Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 101, Pages: 055003-1-055003-6, ISSN: 1550-2368

    We show that in the SU(2) Georgi-Glashow model, ’t Hooft–Polyakov monopoles are produced by a classical instability in magnetic fields above the Ambjørn-Olesen critical field, which coincides approximately with the field at which Schwinger pair production becomes unsuppressed. Below it, monopoles can be produced thermally, and we show that the rate is higher than for pointlike monopoles by calculating the sphaleron energy as a function of the magnetic field. The results can be applied to production of monopoles in heavy-ion collisions or in the early Universe.
  • Journal article
    Chaemjumrus N, Hull CM, 2020,

    Special holonomy manifolds, domain walls, intersecting branes and T-folds

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479

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