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Journal articleBourget A, Giacomelli S, Grimminger JF, et al., 2021,
S-fold magnetic quivers
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Cite
- Citations: 23
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Journal articleAshmore A, Strickland-Constable C, Tennyson D, et al., 2021,
Generalising G₂ geometry: involutivity, moment maps and moduli
, The Journal of High Energy Physics, Vol: 2021, Pages: 1-66, ISSN: 1029-8479We analyse the geometry of generic Minkowski N = 1, D = 4 flux compactifications in string theory, the default backgrounds for string model building. In M-theory they are the natural string theoretic extensions of G2 holonomy manifolds. In type II theories, they extend the notion of Calabi-Yau geometry and include the class of flux backgrounds based on generalised complex structures first considered by Graña et al. (GMPT). Using E7(7) × ℝ+ generalised geometry we show that these compactifications are characterised by an SU(7) ⊂ E7(7) structure defining an involutive subbundle of the generalised tangent space, and with a vanishing moment map, corresponding to the action of the diffeomorphism and gauge symmetries of the theory. The Kähler potential on the space of structures defines a natural extension of Hitchin’s G2 functional. Using this framework we are able to count, for the first time, the massless scalar moduli of GMPT solutions in terms of generalised geometry cohomology groups. It also provides an intriguing new perspective on the existence of G2 manifolds, suggesting possible connections to Geometrical Invariant Theory and stability.
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Journal articleBeccaria M, Tseytlin AA, 2021,
On the structure of non-planar strong coupling corrections to correlators of BPS Wilson loops and chiral primary operators
, The Journal of High Energy Physics, Vol: 2021, Pages: 1-47, ISSN: 1029-8479Starting with some known localization (matrix model) representations for correlators involving 1/2 BPS circular Wilson loop W in N = 4 SYM theory we work out their 1/N expansions in the limit of large ’t Hooft coupling λ. Motivated by a possibility of eventual matching to higher genus corrections in dual string theory we follow arXiv:2007.08512 and express the result in terms of the string coupling gs∼g2YM∼λ/N and string tension T∼λ−−√. Keeping only the leading in 1/T term at each order in gs we observe that while the expansion of ⟨W⟩ is a series in g2s/T, the correlator of the Wilson loop with chiral primary operators OJ has expansion in powers of g2s/T2. Like in the case of ⟨W⟩ where these leading terms are known to resum into an exponential of a “one-handle” contribution ∼g2s/T, the leading strong coupling terms in ⟨WOJ⟩ sum up to a simple square root function of g2s/T2. Analogous expansions in powers of g2s/T are found for correlators of several coincident Wilson loops and they again have a simple resummed form. We also find similar expansions for correlators of coincident 1/2 BPS Wilson loops in the ABJM theory.
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Journal articleAlday LF, Chester SM, Raj H, 2021,
6d (2, 0) and M-theory at 1-loop
, Journal of High Energy Physics, Vol: 2021<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We study the stress tensor multiplet four-point function in the 6d maximally supersymmetric (2<jats:italic>,</jats:italic> 0) <jats:italic>A</jats:italic><jats:sub><jats:italic>N−</jats:italic>1</jats:sub> and <jats:italic>D</jats:italic><jats:sub><jats:italic>N</jats:italic></jats:sub> theories, which have no Lagrangian description, but in the large <jats:italic>N</jats:italic> limit are holographically dual to weakly coupled M-theory on <jats:italic>AdS</jats:italic><jats:sub>7</jats:sub><jats:italic>× S</jats:italic><jats:sup>4</jats:sup> and <jats:italic>AdS</jats:italic><jats:sub>7</jats:sub><jats:italic>× S</jats:italic><jats:sup>4</jats:sup>/ℤ<jats:sub>2</jats:sub>, respectively. We use the analytic bootstrap 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, which is the first 1-loop correction computed for a non-Lagrangian theory. We then take the flat space limit and find precise agreement with the corresponding terms in the 11d M-theory S-matrix, some of which we compute for the first time using two-particle unitarity cuts.</jats:p>
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Journal articleChester SM, Pufu SS, 2021,
Far beyond the planar limit in strongly-coupled $$ \mathcal{N} $$ = 4 SYM
, Journal of High Energy Physics, Vol: 2021<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>When the SU(<jats:italic>N</jats:italic>) <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) theory with complexified gauge coupling <jats:italic>τ</jats:italic> is placed on a round four-sphere and deformed by an <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> = 2-preserving mass parameter <jats:italic>m</jats:italic>, its free energy <jats:italic>F</jats:italic> (<jats:italic>m, τ,</jats:italic><jats:inline-formula><jats:alternatives><jats:tex-math>$$ \overline{\tau} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>τ</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula>) can be computed exactly using supersymmetric localization. In this work, we derive a new exact relation between the fourth derivative <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {\partial}_m^4F\left(m,\tau, \overline{\tau}\right)\left|{{}_m}_{=0}\right. $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
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Journal articleBourget A, Hanany A, Miketa D, 2021,
Quiver origami: discrete gauging and folding
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Author Web Link
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- Citations: 11
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Journal articleFlauger R, Karnesis N, Nardini G, et al., 2021,
Improved reconstruction of a stochastic gravitational wave background with LISA
, Journal of Cosmology and Astroparticle Physics, Vol: 2021, Pages: 1-34, ISSN: 1475-7516We present a data analysis methodology for a model-independent reconstruction of the spectral shape of a stochastic gravitational wave background with LISA. We improve a previously proposed reconstruction algorithm that relied on a single Time-Delay-Interferometry (TDI) channel by including a complete set of TDI channels. As in the earlier work, we assume an idealized equilateral configuration. We test the improved algorithm with a number of case studies, including reconstruction in the presence of two different astrophysical foreground signals. We find that including additional channels helps in different ways: it reduces the uncertainties on the reconstruction; it makes the global likelihood maximization less prone to falling into local extrema; and it efficiently breaks degeneracies between the signal and the instrumental noise.
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Journal articleDancer A, Hanany A, Kirwan F, 2021,
Symplectic duality and implosions
, ADVANCES IN THEORETICAL AND MATHEMATICAL PHYSICS, Vol: 25, Pages: 1367-1387, ISSN: 1095-0761- Author Web Link
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- Citations: 4
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Journal articleAlberte L, de Rham C, Jaitly S, et al., 2020,
Positivity bounds and the massless spin-2 pole
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 102, Pages: 1-34, ISSN: 1550-2368The presence of a massless spin-2 field in an effective field theory results in a t-channel pole in the scattering amplitudes that precludes the application of standard positivity bounds. Despite this, recent arguments based on compactification to three dimensions have suggested that positivity bounds may be applied to the t-channel pole subtracted amplitude. If correct, this would have deep implications for UV physics and the weak gravity conjecture. Within the context of a simple renormalizable field theory coupled to gravity we find that applying these arguments would constrain the low-energy coupling constants in a way which is incompatible with their actual values. This contradiction persists on deforming the theory. Further enforcing the t-channel pole subtracted positivity bounds on such generic renormalizable effective theories coupled to gravity would imply new physics at a scale parametrically smaller than expected, with far-reaching implications. This suggests that generically the standard positivity bounds are inapplicable with gravity, and we highlight a number of issues that impinge on the formulation of a three-dimensional amplitude which simultaneously satisfies the required properties of analyticity, positivity, and crossing symmetry. We conjecture instead a modified bound that ought to be satisfied independently of the precise details of the high energy completion.
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Journal articleBourget A, Grimminger JF, Hanany A, et al., 2020,
Magnetic lattices for orthosymplectic quivers
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Cite
- Citations: 21
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Conference paperShaw EC, Ade PAR, Akers S, et al., 2020,
Design and pre-flight performance of SPIDER 280 GHz receivers
, SPIE ASTRONOMICAL TELESCOPES + INSTRUMENTATION, Publisher: SPIE, Pages: 1-1In this work we describe upgrades to the Spider balloon-borne telescope in preparation for its second flight, currently planned for December 2021. The Spider instrument is optimized to search for a primordial B-mode polarization signature in the cosmic microwave background at degree angular scales. During its first flight in 2015, Spider mapped ~10% of the sky at 95 and 150 GHz. The payload for the second Antarctic flight will incorporate three new 280 GHz receivers alongside three refurbished 95- and 150 GHz receivers from Spider's first flight. In this work we discuss the design and characterization of these new receivers, which employ over 1500 feedhorn-coupled transition-edge sensors. We describe pre-flight laboratory measurements of detector properties, and the optical performance of completed receivers. These receivers will map a wide area of the sky at 280 GHz, providing new information on polarized Galactic dust emission that will help to separate it from the cosmological signal.
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Journal articleMomeni A, Rumbutis J, Tolley AJ, 2020,
Massive gravity from double copy
, The Journal of High Energy Physics, Vol: 30, Pages: 1-36, ISSN: 1029-8479We consider the double copy of massive Yang-Mills theory in four dimensions, whose decoupling limit is a nonlinear sigma model. The latter may be regarded as the leading terms in the low energy effective theory of a heavy Higgs model, in which the Higgs has been integrated out. The obtained double copy effective field theory contains a massive spin-2, massive spin-1 and a massive spin-0 field, and we construct explicitly its interacting Lagrangian up to fourth order in fields. We find that up to this order, the spin-2 self interactions match those of the dRGT massive gravity theory, and that all the interactions are consistent with a Λ3 = (m2MPl)1/3 cutoff. We construct explicitly the Λ3 decoupling limit of this theory and show that it is equivalent to a bi-Galileon extension of the standard Λ3 massive gravity decoupling limit theory. Although it is known that the double copy of a nonlinear sigma model is a special Galileon, the decoupling limit of massive Yang-Mills theory is a more general Galileon theory. This demonstrates that the decoupling limit and double copy procedures do not commute and we clarify why this is the case in terms of the scaling of their kinematic factors.
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Journal articleRivers R, Evans T, 2020,
How do we avoid imposing the present on the past when modelling spatial interactions?
, Documenta Praehistorica, Vol: 47, Pages: 462-475, ISSN: 1318-6701Theoretical archaeological modelling for describing spatial interactions often adopts contemporary socioeconomic ideas whose C20th language gets translated into historical behaviour with the simplest of lexicons. This can lead to the impression that the past is like the present. Our intention in this paper is that, when this happens, to strip out as much of the contemporary context as we can, to bring modelling back to basic epistemic propositions. We suggest that although the underlying ontology may be specific to contemporary society the epistemology has much greater generality, leading to essentially the same conclusions without the carapace of intricate economics.
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Working paperDuff MJ, Stelle KS, 2020,
Sir Thomas Walter Bannerman Kibble CBE
, Publisher: arXivProfessor Tom Kibble was an internationally-renowned theoretical physicistwhose contributions to theoretical physics range from the theory of elementaryparticles to modern early-universe cosmology. The unifying theme behind all hiswork is the theory of non-abelian gauge theories, the Yang-Mills extension ofelectromagnetism. One of Kibble's most important pieces of work in this areawas his study of the symmetry-breaking mechanism whereby the force-carryingvector particles in the theory can acquire a mass accompanied by the appearanceof a massive scalar boson. This idea, put forward independently by Brout andEnglert, by Higgs and by Guralnik, Hagen and Kibble in 1964, and generalised byKibble in 1967, lies at the heart of the Standard Model and all modern unifiedtheories of fundamental particles. It was vindicated in 2012 by the discoveryof the Higgs boson at CERN. According to Nobel Laureate Steven Weinberg, "TomKibble showed us why light is massless"; this is the fundamental basis ofelectromagnetism.
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Journal articleKaram A, Markkanen T, Marzola L, et al., 2020,
Novel mechanism for primordial perturbations in minimal extensions of the Standard Model
, The Journal of High Energy Physics, Vol: 2020, ISSN: 1029-8479We demonstrate that light spectator fields in their equilibrium can source sizeable CMB anisotropies through modulated reheating even in the absence of direct couplings to the inflaton. The effect arises when the phase space of the inflaton decay is modulated by the spectator which generates masses for the decay products. We call the mechanism indirect modulation and using the stochastic eigenvalue expansion show that it can source perturbations even four orders of magnitude larger than the observed amplitude. Importantly, the indirect mechanism is present in the Standard Model extended with right- handed neutrinos. For a minimally coupled Higgs boson this leads to a novel lower bound on the quartic coupling and constrains the neutrino Yukawas below unity.
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Working paperArav I, Cheung KCM, Gauntlett JP, et al., 2020,
Spatially modulated and supersymmetric mass deformations of N=4 SYM
, Publisher: arXivWe study mass deformations of $\mathcal{N}=4$, $d=4$ SYM theory that arespatially modulated in one spatial dimension and preserve some residualsupersymmetry. We focus on generalisations of $\mathcal{N}=1^*$ theories andshow that it is also possible, for suitably chosen supersymmetric masses, topreserve $d=3$ conformal symmetry associated with a co-dimension one interface.Holographic solutions can be constructed using $D=5$ theories of gravity thatarise from consistent truncations of $SO(6)$ gauged supergravity and hence typeIIB supergravity. For the mass deformations that preserve $d=3$ superconformalsymmetry we construct a rich set of Janus solutions of $\mathcal{N}=4$ SYMtheory which have the same coupling constant on either side of the interface.Limiting classes of these solutions give rise to RG interface solutions with$\mathcal{N}=4$ SYM on one side of the interface and the Leigh-Strassler (LS)SCFT on the other, and also to a Janus solution for the LS theory. Anotherlimiting solution is a new supersymmetric $AdS_4\times S^1\times S^5$ solutionof type IIB supergravity.
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Journal articleAshmore A, Strickland-Constable C, Tennyson D, et al., 2020,
Heterotic backgrounds via generalised geometry: moment maps and moduli
, The Journal of High Energy Physics, Vol: 2020, Pages: 1-46, ISSN: 1029-8479We describe the geometry of generic heterotic backgrounds preserving minimal supersymmetry in four dimensions using the language of generalised geometry. They are characterised by an SU(3) × Spin(6 + n) structure within O(6, 6 + n) × ℝ+ generalised geometry. Supersymmetry of the background is encoded in the existence of an involutive subbundle of the generalised tangent bundle and the vanishing of a moment map for the action of diffeomorphisms and gauge symmetries. We give both the superpotential and the Kähler potential for a generic background, showing that the latter defines a natural Hitchin functional for heterotic geometries. Intriguingly, this formulation suggests new connections to geometric invariant theory and an extended notion of stability. Finally we show that the analysis of infinitesimal deformations of these geometric structures naturally reproduces the known cohomologies that count the massless moduli of supersymmetric heterotic backgrounds.
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Journal articleCatterall S, Giedt J, Jha RG, et al., 2020,
Three-dimensional super-Yang-Mills theory on the lattice and dual black branes
, PHYSICAL REVIEW D, Vol: 102, ISSN: 2470-0010- Author Web Link
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- Citations: 8
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Journal articleHoare B, Levine N, Tseytlin AA, 2020,
Sigma models with local couplings: a new integrability-RG flow connection
, The Journal of High Energy Physics, Vol: 20, ISSN: 1029-8479We consider several classes of σ-models (on groups and symmetric spaces, η-models, ⋋-models) with local couplings that may depend on the 2d coordinates, e.g. on time τ . We observe that (i) starting with a classically integrable 2d σ-model, (ii) formally promoting its couplings hα to functions hα(τ ) of 2d time, and (iii) demanding that the resulting time-dependent model also admits a Lax connection implies that hα(τ ) must solve the 1-loop RG equations of the original theory with τ interpreted as RG time. This provides a novel example of an ‘integrability-RG flow’ connection. The existence of a Lax connection suggests that these time-dependent σ-models may themselves be understood as integrable. We investigate this question by studying the possibility of constructing non-local and local conserved charges. Such σ-models with D-dimensional target space and time-dependent couplings subject to the RG flow naturally appear in string theory upon fixing the light-cone gauge in a (D + 2)-dimensional conformal σ-model with a metric admitting a covariantly constant null Killing vector and a dilaton linear in the null coordinate.
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Journal articleChester SM, Green MB, Pufu SS, et al., 2020,
Modular invariance in superstring theory from $$ \mathcal{N} $$ = 4 super-Yang-Mills
, Journal of High Energy Physics, Vol: 2020<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We study the four-point function of the lowest-lying half-BPS operators in the <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 SU(<jats:italic>N</jats:italic>) super-Yang-Mills theory and its relation to the flat-space four-graviton amplitude in type IIB superstring theory. We work in a large-<jats:italic>N</jats:italic> expansion in which the complexified Yang-Mills coupling <jats:italic>τ</jats:italic> is fixed. In this expansion, non-perturbative instanton contributions are present, and the SL(2<jats:italic>,</jats:italic> ℤ) duality invariance of correlation functions is manifest. Our results are based on a detailed analysis of the sphere partition function of the mass-deformed SYM theory, which was previously computed using supersymmetric localization. This partition function determines a certain integrated correlator in the undeformed <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 theory, which in turn constrains the four-point correlator at separated points. In a normalization where the two-point functions are proportional to <jats:italic>N</jats:italic><jats:sup>2</jats:sup><jats:italic>−</jats:italic> 1 and are independent of <jats:italic>τ</jats:italic> and <jats:inline-formula><jat
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Working paperArav I, Cheung KCM, Gauntlett JP, et al., 2020,
Superconformal RG interfaces in holography
, Publisher: arXivWe construct gravitational solutions that holographically describe twodifferent $d=4$ SCFTs joined together at a co-dimension one, planar RGinterface and preserving $d=3$ superconformal symmetry. The RG interface joins$\mathcal{N}=4$ SYM theory on one side with the $\mathcal{N}=1$ Leigh-StrasslerSCFT on the other. We construct a family of such solutions, which in generalare associated with spatially dependent mass deformations on the$\mathcal{N}=4$ SYM side, but there is a particular solution for which thesedeformations vanish. We also construct a Janus solution with theLeigh-Strassler SCFT on either side of the interface. Gravitational solutionsassociated with superconformal interfaces involving ABJM theory and two $d=3$$\mathcal{N}=1$ SCFTs with $G_2$ symmetry are also discussed and shown to havesimilar properties, but they also exhibit some new features.
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Journal articlede Rham C, Tolley AJ, 2020,
Causality in curved spacetimes: The speed of light and gravity
, PHYSICAL REVIEW D, Vol: 102, Pages: 1-33, ISSN: 1550-7998Within the low-energy effective field theories of quantum electrodynamics and gravity, the low-energy speed of light or that of gravitational waves can typically be mildly superluminal in curved spacetimes. Related to this, small scattering time advances relative to the curved background can emerge from known effective field theory coefficients for photons or gravitons. We clarify why these results are not in contradiction with causality, analyticity or Lorentz invariance, and highlight various subtleties that arise when dealing with superluminalities and time advances in the gravitational context. Consistent low-energy effective theories are shown to self-protect by ensuring that any time advance and superluminality calculated within the regime of validity of the effective theory is necessarily unresolvable, and cannot be argued to lead to a macroscopically larger light cone. Such considerations are particularly relevant for putting constraints on cosmological and gravitational effective field theories and we provide explicit criteria to be satisfied so as to ensure causality.
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Journal articleGiombi S, Tseytlin AA, 2020,
Strong coupling expansion of circular Wilson loops and string theories in AdS5 x S^5 and AdS4 x CP^3
, The Journal of High Energy Physics, Vol: 2020, Pages: 1-27, ISSN: 1029-8479We revisit the problem of matching the strong coupling expansion of the$\frac{1}{2}$ BPS circular Wilson loops in ${\cal N}=4$ SYM and ABJM gaugetheories with their string theory duals in ${\rm AdS}_5 \times S^5$ and ${\rmAdS}_4 \times CP^3$, at the first subleading (one-loop) order of the expansionaround the minimal surface. We observe that, including the overall factor$1/g_{\rm s}$ of the inverse string coupling constant, as appropriate for theopen string partition function with disk topology, and a universal prefactorproportional to the square root of the string tension $T$, both the SYM andABJM results precisely match the string theory prediction. We provide anexplanation of the origin of the $\sqrt T$ prefactor based on special featuresof the combination of one-loop determinants appearing in the string partitionfunction. The latter also implies a natural generalization $Z_\chi \sim (\sqrtT/g_{\rm s})^\chi$ to higher genus contributions with the Euler number $\chi$,which is consistent with the structure of the $1/N$ corrections found on thegauge theory side.
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Journal articleHilton B, Sood AP, Evans TS, 2020,
Predictive limitations of spatial interaction models: a non-Gaussian analysis
, Scientific Reports, ISSN: 2045-2322We present a method to compare spatial interaction models against data basedon well known statistical measures which are appropriate for such models anddata. We illustrate our approach using a widely used example: commuting data,specifically from the US Census 2000. We find that the radiation model performssignificantly worse than an appropriately chosen simple gravity model. Variousconclusions are made regarding the development and use of spatial interactionmodels, including: that spatial interaction models fit badly to data in anabsolute sense, that therefore the risk of over-fitting is small and addingadditional fitted parameters improves the predictive power of models, and thatappropriate choices of input data can improve model fit.
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Journal articleLee D-S, Lin C-Y, Rivers RJ, 2020,
Large phonon time-of-flight fluctuations in expanding flat condensates of cold Fermi gases
, JOURNAL OF PHYSICS-CONDENSED MATTER, Vol: 32, ISSN: 0953-8984- Author Web Link
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- Citations: 1
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Journal articleFischetti S, Wallis L, Wiseman T, 2020,
Does the round sphere maximize the free energy of (2+1)-dimensional QFTs?
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Author Web Link
- Cite
- Citations: 4
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Journal articlede Rham C, Pozsgay V, 2020,
New class of Proca interactions
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 102, Pages: 1-18, ISSN: 1550-2368We propose a new class of Proca interactions that enjoy a nontrivial constraint and hence propagates the correct number of degrees of freedom for a healthy massive spin-1 field. We show that the scattering amplitudes always differ from those of the Generalized Proca. This implies that the new class of interactions proposed here are genuinely different from the Generalized Proca and there can be no local field redefinitions between the two. In curved spacetime, massive gravity is the natural covariantization, but we show how other classes of covariantizations can be considered.
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Journal articleMargalit A, Contaldi CR, Pieroni M, 2020,
Phase decoherence of gravitational wave backgrounds
, Physical Reveiw DMetric perturbations affect the phase of gravitational waves as theypropagate through the inhomogeneous universe. This effect causes StochasticGravitational Wave Backgrounds (SGWBs) to lose any phase coherence that mayhave been present at emission or horizon entry. We show that, for a standardcosmological model, this implies complete loss of coherence above frequencies$f \sim 10^{-12}$ Hz. The result is that any attempts to map SGWBs usingphase-coherent methods have no foreseeable applications. Incoherent methodsthat solve directly for the intensity of the SGWBs are the only methods thatcan reconstruct the angular dependence of any SGWB.
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Journal articleErickson CW, Harrold AD, Leung R, et al., 2020,
Covert symmetry breaking
, The Journal of High Energy Physics, Vol: 2020, Pages: 1-26, ISSN: 1029-8479Reduction from a higher-dimensional to a lower-dimensional field theory can display special features when the zero-level ground state has nontrivial dependence on the reduction coordinates. In particular, a delayed ‘covert’ form of spontaneous symmetry breaking can occur, revealing itself only at fourth order in the lower-dimensional effective field theory action. This phenomenon is explored in a simple model of (d + 1)-dimensional scalar QED with one dimension restricted to an interval with Dirichlet/Robin boundary conditions on opposing ends. This produces an effective d-dimensional theory with Maxwellian dynamics at the free theory level, but with unusual symmetry breaking appearing in the quartic vector-scalar interaction terms. This simple model is chosen to illuminate the mechanism of effects which are also noted in gravitational braneworld scenarios.
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Journal articleHanany A, Zajac A, 2020,
Ungauging schemes and Coulomb branches of non-simply laced quiver theories
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Author Web Link
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- Citations: 10
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