Publications

Journal article

Ho DL-J, Rajantie A, 2021,

Instanton solution for Schwinger production of 't Hooft-Polyakov monopoles

, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 103, Pages: 1-9, ISSN: 1550-2368

We present the results of an explicit numerical computation of a novel instanton in Georgi-Glashow SU(2) theory. The instanton is physically relevant as a mediator of Schwinger production of ’t Hooft–Polyakov magnetic monopoles from strong magnetic fields. In weak fields, the pair production rate has previously been computed using the worldline approximation, which breaks down in strong fields due to the effects of finite monopole size. Using lattice field theory we have overcome this limit, including finite monopole size effects to all orders. We demonstrate that a full consideration of the internal monopole structure results in an enhancement to the pair production rate, and confirm earlier results that monopole production becomes classical at the Ambjørn-Olesen critical field strength.

Journal article

Alberte L, de Rham C, Jaitly S, Tolley AJet al., 2021,

QED positivity bounds

, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 103, Pages: 1-26, ISSN: 1550-2368

We apply positivity bounds directly to a U(1) gauge theory with charged scalars and charged fermions, i.e., QED, minimally coupled to gravity. Assuming that the massless t-channel pole may be discarded, we show that the improved positivity bounds are violated unless new physics is introduced at the parametrically low scale Λnew∼(emMPl)1/2, consistent with similar results for scalar field theories, far lower than the scale implied by the weak gravity conjecture. This is sharply contrasted with previous treatments which focus on the application of positivity bounds to the low energy gravitational Euler-Heisenberg effective theory only. We emphasize that the low cutoff is a consequence of applying the positivity bounds under the assumption that the pole may be discarded. We conjecture an alternative resolution that a small amount of negativity, consistent with decoupling limits, is allowed and is not in conflict with standard UV completions, including weakly coupled ones.

Journal article

Xie Y, Zhang J, Silva HO, de Rham C, Witek H, Yunes Net al., 2021,

Square peg in a circular hole: choosing the right ansatz for isolated black holes in generic gravitational theories

, Physical Review Letters, Vol: 126, Pages: 1-7, ISSN: 0031-9007

The metric of a spacetime can be greatly simplified if the spacetime is circular. We prove that in generic effective theories of gravity, the spacetime of a stationary, axisymmetric, and asymptotically flat solution must be circular if the solution can be obtained perturbatively from a solution in the general relativity limit. This result applies to a broad class of gravitational theories that include arbitrary scalars and vectors in their light sector, so long as their nonstandard kinetic terms and nonmininal couplings to gravity are treated perturbatively.

Journal article

Tolley AJ, Wang Z-Y, Zhou S-Y, 2021,

New positivity bounds from full crossing symmetry

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

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Citations: 72

Journal article

Cheamsawat K, Fischetti S, Wallis L, Wiseman Tet al., 2021,

A surprising similarity between holographic CFTs and a free fermion in (2+1) dimensions

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

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Citations: 3

Journal article

Arav I, Cheung KCM, Gauntlett JP, Roberts MM, Rosen Cet al., 2021,

A new family of AdS4 S-folds in type IIB string theory

, The Journal of High Energy Physics, Vol: 2021, Pages: 1-49, ISSN: 1029-8479

We construct infinite new classes of AdS4 × S1 × S5 solutions of type IIB string theory which have non-trivial SL(2, ℤ) monodromy along the S1 direction. The solutions are supersymmetric and holographically dual, generically, to N = 1 SCFTs in d = 3. The solutions are first constructed as AdS4 × ℝ solutions in D = 5 SO(6) gauged supergravity and then uplifted to D = 10. Unlike the known AdS4 × ℝ S-fold solutions, there is no continuous symmetry associated with the ℝ direction. The solutions all arise as limiting cases of Janus solutions of d = 4, N = 4 SYM theory which are supported both by a different value of the coupling constant on either side of the interface, as well as by fermion and boson mass deformations. As special cases, the construction recovers three known S-fold constructions, preserving N = 1, 2 and 4 supersymmetry, as well as a recently constructed N = 1 AdS4 × S1 × S5 solution (not S-folded). We also present some novel “one-sided Janus” solutions that are non-singular.

Journal article

Jones H, 2021,

Comment on 'Solvable model of bound states in the continuum (BIC) in on dimension' (Physica Scripta (2019) 94 105214)

, Physica Scripta: an international journal for experimental and theoretical physics, Vol: 96, Pages: 1-4, ISSN: 0031-8949

We elucidate the status of the special scattering states found in this paper and explore further the relationships between scattering states and bound states of different non-analytic segments (depending on midxmid) of the exponential potential.

Journal article

Athron P, Balazs C, Beniwal A, Camargo-Molina JE, Fowlie A, Gonzalo TE, Hoof S, Kahlhoefer F, Marsh DJE, Prim MT, Scaffidi A, Scott P, Su W, White M, Wu L, Zhang Yet al., 2021,

Global fits of axion-like particles to XENON1T and astrophysical data

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

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Citations: 22

Journal article

Levine N, Tseytlin AA, 2021,

Integrability vs. RG flow in G x G and G x G/H sigma models

, The Journal of High Energy Physics, Vol: 2021, Pages: 1-32, ISSN: 1029-8479

We consider a class of 2d σ-models on products of group spaces that provide new examples of a close connection between integrability and stability under the RG flow. We first study the integrable G × G model derived from the affine Gaudin construction (for which the 1-loop β-functions were found in arXiv:2010.07879) and show that its condition of integrability is preserved also by the 2-loop RG flow. We then investigate the RG flow in the gauged G × G/H model, in particular the integrable T1,1 model found in arXiv:2010.05573. We also construct a new class of integrable G × G/H models in the case when the subgroup H is abelian. In the simplest case of G = SU2, H = U1 this leads to an integrable σ-model on the T1,q space (with a particular B-field). This model is also shown to be stable under the 2-loop RG flow, and we relate this property to its invariance under T-duality in an isometric U1 direction. This T1,q model may be interpreted as an integrable deformation of the GMM model (of two coupled WZW theories with generic levels) away from the conformal point.

Journal article

Magueijo J, Zlosnik T, 2021,

Quantum torsion and a Hartle-Hawking beam

, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 103, Pages: 1-11, ISSN: 1550-2368

In the Einstein-Cartan framework the torsion-free conditions arise within the Hamiltonian treatment as second-class constraints. The standard strategy is to solve these constraints, eliminating the torsion from the classical theory, before quantization. Here we advocate leaving the torsion inside the other constraints before quantization, leading at first to wave functions that can be called “kinematical” with regards to the torsion, but not the other constraints. The torsion-free condition can then be imposed as a condition upon the physical wave packets one constructs, satisfying the usual uncertainty relations, and so with room for quantum fluctuations in the torsion. This alternative strategy has the surprising effect of clarifying the sense in which the wave functions solving an explicitly real theory are “delta-function normalizable.” Such solutions with zero (or any fixed) torsion, should be interpreted as plane waves in torsion space. Properly constructed wave packets are therefore normalizable in the standard sense. Given that they are canonical duals, this statement applies equally well to the Chern-Simons state (connection representation) and the Hartle-Hawking wave function (metric representation). We show how, when torsion is taken into account, the Hartle-Hawking wave function is replaced by a Gauss-Airy function, with finite norm, which we call the Hartle-Hawking beam. The Chern-Simons state, instead, becomes a packet with a Gaussian probability distribution in connection space. We conclude the paper with two sections explaining how to generalize these results beyond minisuperspace.

Journal article

Alexander S, Herczeg G, Magueijo J, 2021,

A generalized Hartle-Hawking wave function

, Classical and Quantum Gravity, Vol: 38, Pages: 1-15, ISSN: 0264-9381

The Hartle–Hawking wave function is known to be the Fourier dual of the Chern–Simons or Kodama state reduced to mini-superspace, using an integration contour covering the whole real line. But since the Chern–Simons state is a solution of the Hamiltonian constraint (with a given ordering), its Fourier dual should provide a solution (i.e. beyond mini-superspace) of the Wheeler DeWitt equation representing the Hamiltonian constraint in the metric representation. We write down a formal expression for such a wave function, to be seen as the generalization beyond mini-superspace of the Hartle–Hawking wave function. Its explicit evaluation (or simplification) depends only on the symmetries of the problem, and we illustrate the procedure with anisotropic Bianchi models and with the Kantowski–Sachs model. A significant difference of this approach is that we may leave the torsion inside the wave functions when we set up the ansatz for the connection, rather than setting it to zero before quantization. This allows for quantum fluctuations in the torsion, with far reaching consequences.

Journal article

Bugden M, Hulik O, Valach F, Waldram Det al., 2021,

G-Algebroids: a unified framework for exceptional and generalised geometry, and poisson-lie duality

, Fortschritte Der Physik/Progress of Physics, Vol: 69, Pages: 1-11, ISSN: 0015-8208

We introduce the notion of urn:x-wiley:00158208:media:prop202100028:prop202100028-math-0001-algebroid, generalising both Lie and Courant algebroids, as well as the algebroids used in urn:x-wiley:00158208:media:prop202100028:prop202100028-math-0002 exceptional generalised geometry for urn:x-wiley:00158208:media:prop202100028:prop202100028-math-0003. Focusing on the exceptional case, we prove a classification of “exact” algebroids and translate the related classification of Leibniz parallelisable spaces into a tractable algebraic problem. After discussing the general notion of Poisson–Lie duality, we show that the Poisson–Lie U-duality is compatible with the equations of motion of supergravity.

Journal article

Binder DJ, Chester SM, Jerdee M, Pufu SSet al., 2021,

The 3d $$ \mathcal{N} $$ = 6 bootstrap: from higher spins to strings to membranes

, Journal of High Energy Physics, Vol: 2021

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We study the space of 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> = 6 SCFTs by combining numerical bootstrap techniques with exact results derived using supersymmetric localization. First we derive the superconformal block decomposition of the four-point function of the stress tensor multiplet superconformal primary. We then use supersymmetric localization results for 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> = 6 U(<jats:italic>N</jats:italic>)<jats:sub><jats:italic>k</jats:italic></jats:sub> × U(<jats:italic>N</jats:italic> + <jats:italic>M</jats:italic>)<jats:sub><jats:italic>−k</jats:italic></jats:sub> Chern-Simons-matter theories to determine two protected OPE coefficients for many values of <jats:italic>N, M, k</jats:italic>. These two exact inputs are combined with the numerical bootstrap to compute precise rigorous islands for a wide range of <jats:italic>N, k</jats:italic> at <jats:italic>M</jats:italic> = 0, so that we can non-perturbatively interpolate between SCFTs with M-theory duals at small <jats:italic>k</jats:italic> and string theory duals at large <jats:italic>k</jats:italic>. We also present evidence that the localization results for

Journal article

Beccaria M, Tseytlin AA, 2021,

1/N expansion of circular Wilson loop in N=2 superconformal SU(N) x SU(N) quiver

, The Journal of High Energy Physics, Vol: 2021, Pages: 1-33, ISSN: 1029-8479

Localization approach to N = 2 superconformal SU(N) × SU(N) quiver theory leads to a non-Gaussian two-matrix model representation for the expectation value of BPS circular SU(N) Wilson loop ⟨W⟩. We study the subleading 1/N2 term in the large N expansion of ⟨W⟩ at weak and strong coupling. We concentrate on the case of the symmetric quiver with equal gauge couplings which is equivalent to the ℤ2 orbifold of the SU(2N) N = 4 SYM theory. This orbifold gauge theory should be dual to type IIB superstring in AdS5 × (S5/ℤ2). We present a string theory argument suggesting that the 1/N2 term in ⟨W⟩ in the orbifold theory should have the same strong-coupling asymptotics λ3/2 as in the N = 4 SYM case. We support this prediction on the gauge theory side by a numerical study of the localization matrix model. We also find a relation between the 1/N2 term in the Wilson loop expectation value and the derivative of the free energy of the orbifold gauge theory on 4-sphere.

Journal article

Chester SM, Green MB, Pufu SS, Wang Y, Wen Cet al., 2021,

New modular invariants in $$ \mathcal{N} $$ = 4 Super-Yang-Mills theory

, Journal of High Energy Physics, Vol: 2021

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We study modular invariants arising in the four-point functions of the stress tensor multiplet operators of 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, in the limit where <jats:italic>N</jats:italic> is taken to be large while the complexified Yang-Mills coupling <jats:italic>τ</jats:italic> is held fixed. The specific four-point functions we consider are integrated correlators obtained by taking various combinations of four derivatives of the squashed sphere partition function of 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> = 2<jats:sup><jats:italic>∗</jats:italic></jats:sup> theory with respect to the squashing parameter <jats:italic>b</jats:italic> and mass parameter <jats:italic>m</jats:italic>, evaluated at the values <jats:italic>b</jats:italic> = 1 and <jats:italic>m</jats:italic> = 0 that correspond to 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>

Conference paper

Acharya B, Alexandre J, Beneš P, Bergmann B, Bevan A, Billoud T, Branzas H, Burian P, Campbell M, Cecchini S, Cho YM, de Montigny M, de Roeck A, Ellis JR, El Sawy MMH, Fairbairn M, Felea D, Frank M, Garvey D, Hays J, Hirt AM, Janecek J, Kalliokoski M, Korzenev A, Lacarrère DH, Leroy C, Levi G, Lionti A, Mánek P, Maulik A, Margiotta A, Mauri N, Mavromatos NE, Meduna L, Mermod P, Millward L, Mitsou VA, Ostrovskiy I, Ouimet PP, Papavassiliou J, Parker B, Patrizii L, Pavalas GE, Pinfold JL, Popa LA, Popa V, Pozzato M, Pospíšil S, Rajantie A, de Austri RR, Sahnoun Z, Sakellariadou M, Santra A, Sarkar S, Semenoff G, Shaa A, Sirri G, Sliwa K, Smolyanskiy P, Soluk R, Spurio M, Staelens M, Suk M, Tenti M, Togo V, Tuszynski JA, Upreti A, Vento V, Vives O, Wall A, White Eet al., 2021,

Timepix3 as a solid-state time-projection chamber in particle and nuclear physics

Timepix3 devices are hybrid pixel detectors developed within the Medipix3 collaboration at CERN providing a simultaneous measurement of energy (ToT) and time of arrival (ToA) in each of its 256 × 256 pixels (pixel pitch: 55 µm). The timestamp resolution below 2 ns allows a measurement of charge carrier drift times, so that particle trajectories can be reconstructed in 3D on a microscopic level (z-resolution: 30-60 µm). The 3D trajectory reconstruction methodology developed elsewhere is validated against simulated data providing ground truth information of the incident angles. The detector response functions and the achievable track angular resolutions are determined. For the first time, data taken with Timepix3 in the MoEDAL experiment are presented. After extracting singly charged minimum ionizing particle (MIP) tracks from the mixed radiation field using characteristic track features, their impact angles are evaluated. The directionality of the MIP radiation field is shown in elevation angle (?) versus azimuthal angle (?) maps, “unfolded” using the simulated detector responses to an omnidirectional radiation field.

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Citations: 2

Journal article

Chester SM, Kalloor RR, Sharon A, 2021,

Squashing, mass, and holography for 3d sphere free energy

, Journal of High Energy Physics, Vol: 2021

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We consider the sphere free energy <jats:italic>F</jats:italic>(<jats:italic>b</jats:italic>; <jats:italic>m</jats:italic><jats:sub><jats:italic>I</jats:italic></jats:sub>) 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> = 6 ABJ(M) theory deformed by both three real masses <jats:italic>m</jats:italic><jats:sub><jats:italic>I</jats:italic></jats:sub> and the squashing parameter <jats:italic>b</jats:italic>, which has been computed in terms of an <jats:italic>N</jats:italic> dimensional matrix model integral using supersymmetric localization. We show that setting <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {m}_3=i\frac{b-{b}^{-1}}{2} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>m</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:mo>=</mml:mo> <mml:mi>i</mml:mi> <mml:mfrac> <mml:mrow> <mml:mi>b</mml:mi> <mml:mo>−</mml:mo> <mml:msup> <mml:mi>b</mml:mi> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> <

Journal article

Binder DJ, Chester SM, Jerdee M, 2021,

ABJ correlators with weakly broken higher spin symmetry

, Journal of High Energy Physics, Vol: 2021

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We consider four-point functions of operators in the stress tensor multiplet of the 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> = 6 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:italic>M</jats:italic>)<jats:sub><jats:italic>−k</jats:italic></jats:sub> or SO(2)<jats:sub>2<jats:italic>k</jats:italic></jats:sub><jats:italic>×</jats:italic> USp(2 + 2<jats:italic>M</jats:italic>)<jats:sub><jats:italic>−k</jats:italic></jats:sub> ABJ theories in the limit where <jats:italic>M</jats:italic> and <jats:italic>k</jats:italic> are taken to infinity while <jats:italic>N</jats:italic> and <jats:italic>λ</jats:italic> ∼ <jats:italic>M/k</jats:italic> are held fixed. In this limit, these theories have weakly broken higher spin symmetry and are holographically dual to <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> = 6 higher spin gravity on <jats:italic>AdS</jats:italic><jats:sub>4</jats:sub>, where <jats:italic>λ</jats:italic> i

Journal article

Bansal S, Evnin O, Mkrtchyan K, 2021,

Polynomial duality-symmetric lagrangians for free <i>p</i>-forms

, EUROPEAN PHYSICAL JOURNAL C, Vol: 81, ISSN: 1434-6044

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Journal article

Aharony O, Chester SM, Urbach EY, 2021,

A derivation of AdS/CFT for vector models

, Journal of High Energy Physics, Vol: 2021

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We explicitly rewrite the path integral for the free or critical <jats:italic>O</jats:italic>(<jats:italic>N</jats:italic>) (or U(<jats:italic>N</jats:italic>)) bosonic vector models in <jats:italic>d</jats:italic> space-time dimensions as a path integral over fields (including massless high-spin fields) living on (<jats:italic>d</jats:italic> + 1)-dimensional anti-de Sitter space. Inspired by de Mello Koch, Jevicki, Suzuki and Yoon and earlier work, we first rewrite the vector models in terms of bi-local fields, then expand these fields in eigenmodes of the conformal group, and finally map these eigenmodes to those of fields on anti-de Sitter space. Our results provide an explicit (non-local) action for a high-spin theory on anti-de Sitter space, which is presumably equivalent in the large <jats:italic>N</jats:italic> limit to Vasiliev’s classical high-spin gravity theory (with some specific gauge-fixing to a fixed background), but which can be used also for loop computations. Our mapping is explicit within the 1<jats:italic>/N</jats:italic> expansion, but in principle can be extended also to finite <jats:italic>N</jats:italic> theories, where extra constraints on products of bulk fields need to be taken into account.</jats:p>

Journal article

Ferrero P, Gauntlett JP, Ipiña JMP, Martelli D, Sparks Jet al., 2021,

D3-branes wrapped on a spindle

, Physical Review Letters, Vol: 126, ISSN: 0031-9007

We construct supersymmetric AdS_{3}×Σ solutions of minimal gauged supergravity in D=5, where Σ is a two-dimensional orbifold known as a spindle. Remarkably, these uplift on S^{5}, or more generally on any regular Sasaki-Einstein manifold, to smooth solutions of type IIB supergravity. The solutions are dual to d=2, N=(0,2) SCFTs and we show that the central charge for the gravity solution agrees with a field theory calculation associated with D3-branes wrapped on Σ.

Journal article

Dowker F, 2021,

Boundary contributions in the causal set action

, Classical and Quantum Gravity, Vol: 38, ISSN: 0264-9381

Evidence is provided for a conjecture that, in the continuum limit, the mean of the causal set action of a causal set sprinkled into a globally hyperbolic Lorentzian spacetime, M, of finite volume equals the Einstein Hilbert action of M plus the volume of the co-dimension 2 intersection of the future boundary with the past boundary. We give the heuristic argument for this conjecture and analyse some examples in 2 dimensions and one example in 4 dimensions.

Journal article

Mantziris A, Markkanen T, Rajantie A, 2021,

Vacuum decay constraints on the Higgs curvature coupling from inflation

, Journal of Cosmology and Astroparticle Physics, Vol: 2021, Pages: 1-22, ISSN: 1475-7516

We derive lower bounds for the Higgs-curvature coupling from vacuum stability during inflation in three inflationary models: quadratic and quartic chaotic inflation, and Starobinsky-like power-law inflation. In contrast to most previous studies we take the time-dependence of the Hubble rate into account both in the geometry of our past light-cone and in the Higgs effective potential, which is approximated with three-loop renormalisation group improvement supplemented with one-loop curvature corrections. We find that in all three models, the lower bound is ξ≳ 0.051... 0.066 depending on the top quark mass. We also demonstrate that vacuum decay is most likely to happen a few e-foldings before the end of inflation.

Journal article

Orlando G, Pieroni M, Ricciardone A, 2021,

Measuring parity violation in the Stochastic Gravitational Wave Background with the LISA-Taiji network

, JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, ISSN: 1475-7516

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Citations: 25

Journal article

Cassani D, Josse G, Petrini M, Waldram Det al., 2021,

N=2 consistent truncations from wrapped M5-branes

, The Journal of High Energy Physics, Vol: 2021, Pages: 1-69, ISSN: 1029-8479

We discuss consistent truncations of eleven-dimensional supergravity on a six-dimensional manifold M, preserving minimal N = 2 supersymmetry in five dimensions. These are based on GS ⊆ USp(6) structures for the generalised E6(6) tangent bundle on M, such that the intrinsic torsion is a constant GS singlet. We spell out the algorithm defining the full bosonic truncation ansatz and then apply this formalism to consistent truncations that contain warped AdS5 ×w M solutions arising from M5-branes wrapped on a Riemann surface. The generalised U(1) structure associated with the N = 2 solution of Maldacena-Nuñez leads to five-dimensional supergravity with four vector multiplets, one hypermultiplet and SO(3) × U(1) × ℝ gauge group. The generalised structure associated with “BBBW” solutions yields two vector multiplets, one hypermultiplet and an abelian gauging. We argue that these are the most general consistent truncations on such backgrounds.

Journal article

Barrow JD, Magueijo J, 2021,

A contextual Planck parameter and the classical limit in quantum cosmology

, Foundations of Physics: an international journal devoted to the conceptual and fundamental theories of modern physics, biophysics, and cosmology, Vol: 51, ISSN: 0015-9018

We propose that whatever quantity controls the Heisenberg uncertainty relations (for a given complementary pair of observables) it should be identified with an effective Planck parameter. With this definition it is not difficult to find examples where the Planck parameter depends on the region under study, varies in time, and even depends on which pair of observables one focuses on. In quantum cosmology the effective Planck parameter depends on the size of the comoving region under study, and so depends on that chosen region and on time. With this criterion, the classical limit is expected, not for regions larger than the Planck length, lP, but for those larger than lQ=(l2PH−1)1/3, where H is the Hubble parameter. In theories where the cosmological constant is dynamical, it is possible for the latter to remain quantum even in contexts where everything else is deemed classical. These results are derived from standard quantization methods, but we also include more speculative cases where ad hoc Planck parameters scale differently with the length scale under observation. Even more speculatively, we examine the possibility that similar complementary concepts affect thermodynamical variables, such as the temperature and the entropy of a black hole.

Journal article

Acharya B, Alexandre J, Benes P, Bergmann B, Bernabeu J, Bevan A, Branzas H, Burian P, Campbell M, Cecchini S, Cho YM, de Montigny M, De Roeck A, Ellis JR, El Sawy M, Fairbairn M, Felea D, Frank M, Hays J, Hirt AM, Janecek J, Kalliokoski M, Korzenev A, Lacarrere DH, Leroy C, Levi G, Lionti A, Mamuzic J, Maulik A, Margiotta A, Mauri N, Mavromatos NE, Mermod P, Mieskolainen M, Millward L, Mitsou VA, Orava R, 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, Ruiz de Austri R, 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, Tuszynski JA, Upreti A, Vento V, Vives O, Wall Aet al., 2021,

First Search for dyons with the full MoEDAL trapping detector in 13 TeV pp collisions

, Physical Review Letters, Vol: 126, ISSN: 0031-9007

The MoEDAL trapping detector consists of approximately 800 kg of aluminum volumes. It was exposed during run 2 of the LHC program to 6.46 fb−1 of 13 TeV proton-proton collisions at the LHCb interaction point. Evidence for dyons (particles with electric and magnetic charge) captured in the trapping detector was sought by passing the aluminum volumes comprising the detector through a superconducting quantum interference device (SQUID) magnetometer. The presence of a trapped dyon would be signaled by a persistent current induced in the SQUID magnetometer. On the basis of a Drell-Yan production model, we exclude dyons with a magnetic charge ranging up to five Dirac charges (5gD) and an electric charge up to 200 times the fundamental electric charge for mass limits in the range 870–3120 GeV and also monopoles with magnetic charge up to and including 5gD with mass limits in the range 870–2040 GeV.

Journal article

Bourget A, Giacomelli S, Grimminger JF, Hanany A, Sperling M, Zhong Zet al., 2021,

S-fold magnetic quivers

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

Cite
Citations: 23

Journal article

Ashmore A, Strickland-Constable C, Tennyson D, Waldram Det al., 2021,

Generalising G₂ geometry: involutivity, moment maps and moduli

, The Journal of High Energy Physics, Vol: 2021, Pages: 1-66, ISSN: 1029-8479

We 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.

Journal article

Beccaria 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: 1029-8479

Starting 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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Timepix3 as a solid-state time-projection chamber in particle and nuclear physics

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