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  • Journal article
    Alday LF, Chester SM, 2022,

    Pure Anti-de Sitter Supergravity and the Conformal Bootstrap.

    , Phys Rev Lett, Vol: 129

    We consider graviton scattering in maximal supergravity on anti-de Sitter space (AdS) in d+1 dimensions for d=3, 4, and 6 with no extra compact spacetime factor. Holography suggests that this theory is dual to an exotic maximally supersymmetric conformal field theory (CFT) in d dimensions whose only light single trace operator is the stress tensor. This contrasts with more standard cases like type IIB string theory on AdS_{5}×S^{5} dual to N=4 super-Yang-Mills, where the CFT has light single trace operators for each Kaluza-Klein mode on S^{5}. We compute the one-loop correction to the pure AdS_{d+1} theory in a small Planck length expansion, which is dual to the large central charge expansion in the CFT. We find that this correction saturates the most general nonperturbative conformal bootstrap bounds on this correlator in the large central charge regime for d=3, 4, 6, while the one-loop correction to CFTs with string and M-theory duals all lie inside the allowed region.
  • Journal article
    Albertini E, Alexander S, Herczeg G, Magueijo Jet al., 2022,

    Torsion and the probability of inflation

    , Journal of Cosmology and Astroparticle Physics, Vol: 2022, Pages: 1-14, ISSN: 1475-7516

    We revisit the problem of the "probability of inflation" from the point of view of the Einstein-Cartan theory, where torsion can be present off-shell even in the absence of spinorial currents. An informal estimate suggests that the barrier for tunneling from "nothing" into a classical universe becomes thinner and lower, should torsion be present, even if only off-shell. We perform a detailed calculation that supports this informal estimate for the case of torsion eigenstates. Finally, we impose a quantum mechanical analog of the zero-torsion condition by restricting to states for which the expectation value of the torsion vanishes. An explicit family of such states is obtained by building wave-packets from linear superpositions of torsion eigenstates with Gaussian weights centered around zero torsion. The tunneling probability for these wave packets is maximized when the variance of the torsion goes to zero. Hence, by considering these wave-packets as the physical states, we recover a sensible model of quantum cosmology that incorporates quantum fluctuations in the torsion, despite the apparently unacceptable conclusions one draws from naïvely considering the tunneling probabilities for the torsion eigenstates.
  • Journal article
    Alday LF, Chester SM, Raj H, 2022,

    M-theory on AdS4 × S7 at 1-loop and beyond

    , Journal of High Energy Physics, Vol: 2022

    <jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We study graviton scattering on <jats:italic>AdS</jats:italic><jats:sub>4</jats:sub><jats:italic>× S</jats:italic><jats:sup>7</jats:sup>, which is dual to the stress tensor multiplet four-point function in the maximally supersymmetric 3d U(<jats:italic>N</jats:italic>)<jats:sub>1</jats:sub><jats:italic>×</jats:italic> U(<jats:italic>N</jats:italic>)<jats:sub><jats:italic>−</jats:italic>1</jats:sub> ABJM theory. We compute 1-loop corrections to this holographic correlator coming from Witten diagrams with supergravity <jats:italic>R</jats:italic> and higher derivative <jats:italic>R</jats:italic><jats:sup>4</jats:sup> vertices, up to contact term ambiguities, and find that the flat space limit matches the corresponding terms in the 11d M-theory S-matrix. We then use supersymmetric localization to show that all the 1-loop contact terms vanish, as was previously observed for the <jats:italic>AdS</jats:italic><jats:sub>4</jats:sub><jats:italic>× S</jats:italic><jats:sup>7</jats:sup><jats:italic>/</jats:italic>ℤ<jats:sub>2</jats:sub> theory dual to U(<jats:italic>N</jats:italic>)<jats:sub>2</jats:sub><jats:italic>×</jats:italic> U(<jats:italic>N</jats:italic>)<jats:sub><jats:italic>−</jats:italic>2</jats:sub> ABJM. Finally, we use the recent localization results of Gaiotto and Abajian, as inspired by twisted M-theory, to compute all the short OPE coefficients in correlators of the stress tensor multiplet and the next lowest half-BPS operator, which we find saturate the bootstrap bounds on these mixed correlators for all <jats:ital
  • Journal article
    Hanany A, Sperling M, 2022,

    Magnetic quivers and negatively charged branes

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Journal article
    Bartolo N, Bertacca D, Caldwell R, Contaldi CR, Cusin G, De Luca V, Dimastrogiovanni E, Fasiello M, Figueroa DG, Franciolini G, Jenkins AC, Peloso M, Pieroni M, Renzini A, Ricciardone A, Riotto A, Sakellariadou M, Sorbo L, Tasinato G, Torrado J, Clesse S, Kuroyanagi Set al., 2022,

    Probing anisotropies of the Stochastic Gravitational Wave Background with LISA

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

    We investigate the sensitivity of the Laser Interferometer Space Antenna (LISA) to the anisotropies of the Stochastic Gravitational Wave Background (SGWB). We first discuss the main astrophysical and cosmological sources of SGWB which are characterized by anisotropies in the GW energy density, and we build a Signal-to-Noise estimator to quantify the sensitivity of LISA to different multipoles. We then perform a Fisher matrix analysis of the prospects of detectability of anisotropic features with LISA for individual multipoles, focusing on a SGWB with a power-law frequency profile. We compute the noise angular spectrum taking into account the specific scan strategy of the LISA detector. We analyze the case of the kinematic dipole and quadrupole generated by Doppler boosting an isotropic SGWB. We find that β ΩGW ∼ 2 × 10-11 is required to observe a dipolar signal with LISA. The detector response to the quadrupole has a factor ∼ 103 β relative to that of the dipole. The characterization of the anisotropies, both from a theoretical perspective and from a map-making point of view, allows us to extract information that can be used to understand the origin of the SGWB, and to discriminate among distinct superimposed SGWB sources.
  • Journal article
    Filippini JP, Gambrel AE, Rahlin AS, Young EY, Ade PAR, Amiri M, Benton SJ, Bergman AS, Bihary R, Bock JJ, Bond JR, Bonetti JA, Bryan SA, Chiang HC, Contaldi CR, Dore O, Duivenvoorden AJ, Eriksen HK, Farhang M, Fraisse AA, Freese K, Galloway M, Gandilo NN, Ganga K, Gualtieri R, Gudmundsson JE, Halpern M, Hartley J, Hasselfield M, Hilton G, Holmes W, Hristov VV, Huang Z, Irwin KD, Jones WC, Karakci A, Kuo CL, Kermish ZD, Leung JS-Y, Li S, Mak DSY, Mason P, Megerian K, Moncelsi L, Morford TA, Nagy JM, Netterfield CB, Nolta M, O'Brient R, Osherson B, Padilla IL, Racine B, Reintsema C, Ruhl JE, Runyan MC, Ruud TM, Shariff JA, Shaw EC, Shiu C, Soler JD, Song X, Trangsrud A, Tucker C, Tucker RS, Turner AD, van der List JF, Weber AC, Wehus IK, Wen S, Wiebe Det al., 2022,

    In-Flight Gain Monitoring of SPIDER's Transition-Edge Sensor Arrays

    , JOURNAL OF LOW TEMPERATURE PHYSICS, Vol: 209, Pages: 649-657, ISSN: 0022-2291
  • Journal article
    Hull C, 2022,

    Gravity, duality and conformal symmetry

    , PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 478, ISSN: 1364-5021
  • Journal article
    Roberts MM, Wiseman T, 2022,

    Reply to"Comment on 'Curved-space Dirac description of elastically deformed monolayer graphene is generally incorrect'"

    , PHYSICAL REVIEW B, Vol: 106, ISSN: 2469-9950
  • Journal article
    Kurlyand SA, Tseytlin AA, 2022,

    Type IIB supergravity action on M5 x X5 solutions

    , Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 106, ISSN: 1550-2368

    While the ten-dimensional type IIB supergravity action evaluated on AdS5×𝑆5 solution vanishes, the five-dimensional effective action reconstructed from equations of motion using the 𝑀5 ×𝑆5 compactification ansatz is proportional to the AdS5 volume. The latter is consistent with the conformal anomaly interpretation in AdS/CFT context. We show that this paradox can be resolved if, in the case of 𝑀5 ×𝑋5 topology, the ten-dimensional action contains an additional 5-form-dependent “topological” term ∫𝐹5⁢𝑀 ∧𝐹5⁢𝑋. The presence of this term is suggested also by gauge-invariance considerations in the Pasti-Sorokin-Tonin formulation of type IIB supergravity action. We show that this term contributes to the ten-dimensional action evaluated on the D3-brane solution.
  • Journal article
    Magueijo J, 2022,

    Connection between cosmological time and the constants of nature

    , PHYSICAL REVIEW D, Vol: 106, Pages: 1-16, ISSN: 2470-0010

    We examine in greater detail the proposal that time is the conjugate of the constants of nature. Fundamentally distinct times are associated with different constants, a situation often found in “relational time” settings. We show how in regions dominated by a single constant the Hamiltonian constraint can be reframed as a Schrödinger equation in the corresponding time, solved in the connection representation by outgoing-only monochromatic plane waves moving in a “space” that generalizes the Chern-Simons functional (valid for the equation of state w=−1) for other w. We pay special attention to the issues of unitarity and the measure employed for the inner product. Normalizable superpositions can be built, including solitons, “light-rays” and coherent/squeezed states saturating a Heisenberg uncertainty relation between constants and their times. A healthy classical limit is obtained for factorizable coherent states, both in monofluid and multifluid situations. For the latter, we show how to deal with transition regions, where one is passing on the baton from one time to another, and investigate the fate of the subdominant clock. For this purpose minisuperspace is best seen as a dispersive medium, with packets moving with a group speed distinct from the phase speed. We show that the motion of the packets’ peaks reproduces the classical limit even during the transition periods, and for subdominant clocks once the transition is over. Deviations from the coherent/semiclassical limit are expected in these cases, however. The fact that we have recently transitioned from a decelerating to an accelerating Universe renders this proposal potentially testable, as explored elsewhere.
  • Journal article
    Arav I, Gauntlett JP, Roberts MM, Rosen Cet al., 2022,

    Leigh-Strassler compactified on a spindle

    , The Journal of High Energy Physics, Vol: 2022, Pages: 1-47, ISSN: 1029-8479

    We construct a new class of supersymmetric AdS3 × Y7 solutions of type IIB supergravity, where Y7 is an S5 fibration over a spindle, which are dual to d = 2, N = (0, 2) SCFTs. The solutions are constructed in a sub-truncation of D = 5, SO(6) maximal gauged supergravity and they all lie within the anti-twist class. We show that the central charge computed from the gravity solutions agrees with an anomaly polynomial calculation associated with compactifying the N = 1, d = 4 Leigh-Strassler SCFT on a spindle.
  • Journal article
    Bertolini M, Mignosa F, van Muiden J, 2022,

    On non-supersymmetric fixed points in five dimensions

    , Journal of High Energy Physics, Vol: 2022

    <jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We generalize recent results regarding the phase space of the mass deformed <jats:italic>E</jats:italic><jats:sub>1</jats:sub> fixed point to a full class of five-dimensional superconformal field theories, known as <jats:italic>X</jats:italic><jats:sub>1,<jats:italic>N</jats:italic></jats:sub>. As in the <jats:italic>E</jats:italic><jats:sub>1</jats:sub> case, a phase transition occurs as a supersymmetry preserving and a supersymmetry breaking mass deformations are appropriately tuned. The order of such phase transition could not be unequivocally determined in the <jats:italic>E</jats:italic><jats:sub>1</jats:sub> case. For <jats:italic>X</jats:italic><jats:sub>1,<jats:italic>N</jats:italic></jats:sub>, instead, we can show that at large <jats:italic>N</jats:italic> there exists a regime where the phase transition is second order. Our findings give supporting evidence for the existence of non-supersymmetric fixed points in five dimensions.</jats:p>
  • Journal article
    Mantziris A, Markkanen T, Rajantie A, 2022,

    The effective Higgs potential and vacuum decay in Starobinsky inflation

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

    Based on the current experimental data, the Standard Model predicts that the current vacuum state of the Universe is metastable, leading to a non-zero rate of vacuum decay through nucleation of bubbles of true vacuum. Our existence implies that there cannot have been any such bubble nucleation events anywhere in our whole past lightcone. We consider a minimal scenario of the Standard Model together with Starobinsky inflation, using three-loop renormalization group improved Higgs effective potential with one-loop curvature corrections. We show that the survival of the vacuum state through inflation places a lower bound ξ ≳ 0.1 on the non-minimal Higgs curvature coupling, the last unknown parameter of the Standard Model. This bound is significantly stronger than in single field inflation models with no Higgs-inflaton coupling. It is also sensitive to the details of the dynamics at the end of inflation, and therefore it can be improved with a more detailed study of that period.
  • Journal article
    Beccaria M, Korchemsky GP, Tseytlin A, 2022,

    Strong coupling expansion in <i>N</i>=2 superconformal theories and the Bessel kernel

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

    We consider strong ’t Hooft coupling expansion in special four-dimensional 𝒩 = 2 superconformal models that are planar-equivalent to 𝒩 = 4 super Yang-Mills theory. Various observables in these models that admit localization matrix model representation can be expressed at large N in terms of a Fredholm determinant of a Bessel operator. The latter previously appeared in the study of level spacing distributions in matrix models and, more recently, in four-point correlation functions of infinitely heavy half-BPS operators in planar 𝒩 = 4 SYM. We use this relation and a suitably generalized Szegő-Akhiezer-Kac formula to derive the strong ’t Hooft coupling expansion of the leading corrections to free energy, half-BPS circular Wilson loop, and certain correlators of chiral primaries operators in the 𝒩 = 2 models. This substantially generalizes partial results in the literature and represents a challenge for dual string theory calculations in AdS/CFT context. We also demonstrate that the resulting strong-coupling expansions suffer from Borel singularities and require adding non-perturbative, exponentially suppressed corrections. As a byproduct of our analysis, we determine the non-perturbative correction to the above mentioned four-point correlator in planar 𝒩 = 4 SYM.
  • Journal article
    Alexandre B, Magueijo J, 2022,

    Possible quantum effects at the transition from cosmological deceleration to acceleration

    , Physical Review D, Vol: 106, Pages: 1-13, ISSN: 2470-0010

    The recent transition from decelerated to accelerated expansion can be seen as a reflection (or “bounce”) in the connection variable, defined by the inverse comoving Hubble length (b=˙a, on shell). We study the quantum cosmology of this process. We use a formalism for obtaining relational time variables either through the demotion of the constants of nature to integration constants, or by identifying fluid constants of motion. We extend its previous application to a toy model (radiation and Λ) to the realistic setting of a transition from dust matter to Λ domination. In the dust and Λ model two time variables may be defined, conjugate to Λ and to the dust constant of motion, and we work out the monochromatic solutions to the Schrödinger equation representing the Hamiltonian constraint. As for their radiation and Λ counterparts, these solutions exhibit “ringing,” whereby the incident and reflected waves interfere, leading to oscillations in the amplitude. In the semiclassical approximation we find that, close to the bounce, the probability distribution becomes double peaked, one peak following a trajectory close to the classical limit but with a Hubble parameter slightly shifted downwards, the other with a value of b stuck at its minimum b=b⋆. Still closer to the transition, the distribution is better approximated by an exponential distribution, with a single peak at b=b⋆, and a (more representative) average b biased towards a value higher than the classical trajectory. Thus, we obtain a distinctive prediction for the average Hubble parameter with redshift: slightly lower than its classical value when z≈0, but potentially much higher than the classical prediction around z∼0.64, where the bounce most likely occurred. The implications for the “Hubble tension” have not escaped us.
  • Journal article
    Mkrtchyan K, Svazas M, 2022,

    Solutions in Nonlinear Electrodynamics and their double copy regular black holes

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Journal article
    Hoare B, Seibold FK, Tseytlin AA, 2022,

    Integrable supersymmetric deformations of AdS(3)x S(3)x T-4

    , The Journal of High Energy Physics, Vol: 2022, Pages: 1-39, ISSN: 1029-8479

    We construct a family of type IIB string backgrounds that are deformations of AdS3 × S3 × T4 with a “squashed” AdS3 × S3 metric supported by a combination of NSNS and RR fluxes. They have global SU(1, 1) × SU(2) symmetry, regular curvature, constant dilaton and preserve 8 supercharges. Upon compactification to 4 dimensions they reduce to N = 2 supersymmetric AdS2 × S2 solutions with electric and magnetic Maxwell fluxes. These type IIB supergravity solutions can be found from the undeformed AdS3 × S3 × T4 background by a combination of T-dualities and S-duality. In contrast to T-duality, S-duality transformations of a type IIB supergravity background do not generally preserve the classical integrability of the corresponding Green-Schwarz superstring sigma model. Nevertheless, we show that integrability is preserved in the present case. Indeed, we find that these backgrounds can be obtained, up to T-dualities, from an integrable inhomogeneous Yang-Baxter deformation (with unimodular Drinfel’d-Jimbo R-matrix) of the original AdS3 × S3 supercoset model.
  • Journal article
    Bourget A, Grimminger JF, Hanany A, Zhong Zet al., 2022,

    The Hasse diagram of the moduli space of instantons

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Journal article
    Gerhardinger M, Giblin JTJJ, Tolley AJ, Trodden Met al., 2022,

    Well-posed UV completion for simulating scalar Galileons

    , Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 106, Pages: 1-10, ISSN: 1550-2368

    The Galileon scalar field theory is a prototypical example of an effective field theory that exhibits the Vainshtein screening mechanism, which is incorporated into many extensions to Einstein gravity. The Galileon describes the helicity-zero mode of gravitational radiation, the presence of which has significant implications for predictions of gravitational waves from orbiting objects and for tests of gravity sensitive to additional polarizations. Because of the derivative nature of their interactions, Galileons are superficially not well posed as effective field theories. Although this property is properly understood merely as an artifact of the effective field theory truncation, and is not theoretically worrisome, at the practical level it nevertheless renders numerical simulation highly problematic. Notwithstanding, previous numerical approaches have successfully evolved the system for reasonable initial data by slowly turning on the interactions. We present here two alternative approaches to improving numerical stability in Galileon numerical simulations. One of these is a minor modification of previous approaches, which introduces a low-pass filter that amounts to imposing a UV cutoff together with a relaxation method of turning on interactions. The second approach amounts to constructing a (numerical) UV completion for which the dynamics of the high momentum modes is under control and for which it is unnecessary to slowly turn on nonlinear interactions. We show that numerical simulations of the UV theory successfully reproduce the correct Galileon dynamics at low energies, consistent with the low-pass filter method and with previous numerical simulations.
  • Journal article
    Acharya B, Alexandre J, Benes P, Bergmann B, Bertolucci S, Bevan A, Bhattacharyya R, Branzas H, Burian P, Campbell M, Cecchini S, Cho YM, de Montigny M, De Roeck A, Ellis JR, ElSawy M, Fairbairn M, Felea D, Frank M, Hays J, Hirt AM, Hung PQ, Janecek J, Kalliokoski M, Korzenev A, Lacarrere DH, Leroy C, Levi G, Lionti A, Margiotta A, Maselek R, Maulik A, Mauri N, Mavromatos NE, Musumeci E, 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, de Austri RR, Sahnoun Z, Sakellariadou M, Sakurai K, Santra A, Sarkar S, Semenoff G, Shaa A, Sirri G, Sliwa K, Soluk R, Spurio M, Staelens M, Suk M, Tenti M, Togo V, Upreti A, Vento V, Vives Oet al., 2022,

    Search for highly-ionizing particles in 𝑝⁢𝑝 collisions at the LHC's Run-1 using the prototype MoEDAL detector

    , European Physical Journal C, Vol: 82, ISSN: 1434-6044

    A search for highly electrically charged objects(HECOs) and magnetic monopoles is presented using 2.2 fb⁻¹ of p− p collision data taken at a centre of mass energy (ECM) of 8 TeV by the MoEDAL detector during LHC’s Run-1. The data were collected using MoEDAL’s prototype Nuclear Track Detectord array and the Trapping Detectorarray. The results are interpreted in terms of Drell–Yan pairproduction of stable HECO and monopole pairs with threespin hypotheses (0, 1/2 and 1). The search provides constraints on the direct production of magnetic monopoles carrying one to four Dirac magnetic charges and with mass limits ranging from 590 GeV/c² to 1TeV/c². Additionally, mass limits are placed on HECOs with charge in the range 10e to 180e, where e is the charge of an electron, for masses between 30 GeV/c² and 1 TeV/c².
  • Journal article
    Avetisyan Z, Evnin O, Mkrtchyan K, 2022,

    Nonlinear (chiral) <i>p</i>-form electrodynamics

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Working paper
    Cheung KCM, Fry JHT, Gauntlett JP, Sparks Jet al., 2022,

    M5-branes wrapped on four-dimensional orbifolds

    , Publisher: ArXiv

    We construct supersymmetric $AdS_3$ solutions of $D=11$ supergravity, dual to$d=2$, $\mathcal{N}=(0,2)$ SCFTs, that are associated with M5-branes wrappingtwo different four-dimensional orbifolds. In one case the orbifold is a spindlefibred over another spindle, while in the other it is a spindle fibred over aRiemann surface with genus $g>1$. We show that the central charges of the $d=2$SCFTs calculated from the gravity solutions agree with field theorycomputations using anomaly polynomials. The new $D=11$ solutions are obtainedafter constructing a new consistent Kaluza-Klein truncation of maximal $D=7$gauged supergravity reduced on a spindle down to $D=5$ minimal gaugedsupergravity.
  • Journal article
    Bourget A, Grimminger JF, Hanany A, Kalveks R, Zhong Zet al., 2022,

    Higgs branches of U/SU quivers via brane locking

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Journal article
    Kaplan DE, Mitridate A, Trickle T, 2022,

    Constraining fundamental constant variations from ultralight dark matter with pulsar timing arrays

    , Physical Review D, Vol: 106, ISSN: 2470-0010

    Pulsar timing arrays (PTAs) are exceptionally sensitive detectors in the frequency band nHz f μHz. Ultralight dark matter (ULDM), with mass in the range 10-23 eV mφ 10-20 eV, is one class of DM models known to generate signals in this frequency window. While purely gravitational signatures of ULDM have been studied previously, in this work we consider two signals in PTAs which arise in the presence of direct couplings between ULDM and ordinary matter. These couplings induce variations in fundamental constants, i.e., particle masses and couplings. These variations can alter the moment of inertia of pulsars, inducing pulsar spin fluctuations via conservation of angular momentum, or induce apparent timing residuals due to reference clock shifts. By using mock data mimicking current PTA datasets, we show that PTA experiments outperform torsion balance and atomic clock constraints for ULDM coupled to electrons, muons, or gluons. In the case of coupling to quarks or photons, we find that PTAs and atomic clocks set similar constraints. Additionally, we discuss how future PTAs can further improve these constraints, and detail the unique properties of these signals relative to the previously studied effects of ULDM on PTAs.
  • Journal article
    Faraoni V, Giusti A, Jose S, Giardino Set al., 2022,

    Peculiar thermal states in the first-order thermodynamics of gravity

    , Physical Review D, Vol: 106, ISSN: 2470-0010

    In the context of the recently proposed first-order thermodynamics of scalar-tensor gravity, we discuss the possibility of zero-temperature states of equilibrium other than Einstein gravity, including pathological Brans-Dicke theory, Palatini f(R) gravity, and cuscuton gravity, all with nondynamical scalar fields. The formalism is extended to Nordström gravity, which contains only a scalar degree of freedom and has negative temperature relative to general relativity.
  • Journal article
    Bourget A, Dancer A, Grimminger JF, Hanany A, Zhong Zet al., 2022,

    Partial implosions and quivers

    , JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
  • Journal article
    Mylova M, Moschou M, Afshordi N, Magueijo Jet al., 2022,

    Non-gaussian signatures of a thermal big bang

    , Journal of Cosmology and Astroparticle Physics, Vol: 2022, Pages: 1-25, ISSN: 1475-7516

    What if Big Bang was hot from its very inception? This is possible in a bimetric theory where the source of fluctuations is thermal, requiring the model to live on a critical boundary in the space of parameters and can be realized when an anti-DBI brane moves within an EAdS2 ×E3 geometry. This setup renders the model unique, with sharp predictions for the scalar spectral index and its running. We investigate the non-Gaussian signatures of this thermal bimetric model, or "bi-thermal" for short. We adapt the standard calculation of non-Gaussianities for P(X,ϕ) models to the thermal nature of the model, emphasising how the bi-thermal peculiarities affect the calculation and alter results. This leads to precise predictions for the shape and amplitude of the three-point function of the bi-thermal model (at tree-level): flocalNL = -3/2 and fequilNL = -2 + 4 √(3)π/9 ≃ 0.4. We also discover a new shape of flattened non-gaussianity ∝ (k1 + k2 - k3)-3/2 + permutations, which is expected due to the excited thermal initial conditions. These results, along with our earlier predictions for the scalar power spectrum, provide sharp targets for the future generation of cosmological surveys.
  • Journal article
    Chen HY, Mitridate A, Trickle T, Zhang Z, Bernardi M, Zurek KMet al., 2022,

    Dark matter direct detection in materials with spin-orbit coupling

    , Physical Review D, Vol: 106, ISSN: 2470-0010

    Semiconductors with O(meV) band gaps have been shown to be promising targets to search for sub-MeV mass dark matter (DM). In this paper we focus on a class of materials where such narrow band gaps arise naturally as a consequence of spin-orbit coupling (SOC). Specifically, we are interested in computing DM-electron scattering and absorption rates in these materials using state-of-the-art density functional theory techniques. To do this, we extend the DM interaction rate calculation to include SOC effects which necessitates a generalization to spin-dependent wave functions. We apply our new formalism to calculate limits for several DM benchmark models using an example ZrTe5 target and show that the inclusion of SOC can substantially alter projected constraints.
  • Journal article
    Evans TS, Chen B, 2022,

    Linking the network centrality measures closeness and degree

    , Communications Physics, Vol: 5, Pages: 1-11, ISSN: 2399-3650

    We propose a non-linear relationship between two of the most importantmeasures of centrality in a network: degree and closeness. Based on ashortest-path tree approximation, we give an analytic derivation that shows theinverse of closeness is linearly dependent on the logarithm of degree. We showthat our hypothesis works well for a range of networks produced from stochasticnetwork models including the Erdos-Reyni and Barabasi-Albert models. We thentest our relation on networks derived from a wide range of real-world dataincluding social networks, communication networks, citation networks, co-authornetworks, and hyperlink networks. We find our relationship holds true within afew percent in most, but not all, cases. We suggest some ways that thisrelationship can be used to enhance network analysis.
  • Journal article
    Adam A, Figueras P, Jacobson T, Wiseman Tet al., 2022,

    Rotating black holes in Einstein-aether theory

    , CLASSICAL AND QUANTUM GRAVITY, Vol: 39, ISSN: 0264-9381

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  5. Now check the box of any publication you want to add to that group. You can use the filters to find what you want and select multiple publications if necessary. 
  6. Scroll to the bottom and click the blue ‘Create new link’ button to link them.
  7. The publications will be added to the group, and will be displayed on the group publications feed within 24 hours (it is not immediate).

Any problems, talk to Tim Evans or the Faculty Web Team.