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Journal articleIsichei R, Magueijo J, 2024,
Unimodular proca theory: breaking the U(1) gauge symmetry of unimodular gravity via a mass term
, European Physical Journal C: Particles and Fields, Vol: 84, ISSN: 1124-1861We study the Hamiltonian structure ofunimodular-like theories, where the cosmological constant(or other supposed constants of nature) are demoted fromfixed parameters to classical constants of motion. No newlocal degrees of freedom are present as a result of a U(1)gauge invariance of the theory. Hamiltonian analysis of theaction reveals that the only possible gauge fixing that canbe enforced is setting the spatial components of the fourvolume time vector T i ≈ 0. As a consequence of this, thegauge-fixed unimodular path integral is equivalent to the minisuperspace unimodular path integral. However, should webreak the U(1) gauge invariance, two things happen: a massless propagating degree of freedom appears, and the (gaugeinvariant) zero-mode receives modified dynamics. The implications are investigated, with the phenomenology dependingcrucially on the target “constant”.
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Journal articleBeccaria M, Tseytlin AA, 2024,
Large N expansion of superconformal index of k=1 ABJM theory and semiclassical M5 brane partition function
, NUCLEAR PHYSICS B, Vol: 1001, ISSN: 0550-3213 -
Journal articleKarapetyan M, Manvelyan R, Mkrtchyan K, 2024,
On correlation functions of higher-spin currents in arbitrary dimensions <i>d</i> > 3
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleChester SM, Su N, 2024,
Bootstrapping Deconfined Quantum Tricriticality
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleSkrzypek T, Tseytlin AA, 2024,
On AdS/CFT duality in the twisted sector of string theory on <i>AdS</i><sub>5</sub> x <i>S</i><SUP>5</SUP><i>/</i>Z<sub>2</sub> orbifold background
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleHulik O, Malek E, Valach F, et al., 2024,
Y-algebroids and <i>E</i><sub>7(7)</sub> x R<SUP>+</SUP>-generalised geometry
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleEvnin O, Joung E, Mkrtchyan K, 2024,
Democratic Lagrangians from topological bulk
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleAggarwal D, He Y-H, Heyes E, et al., 2024,
Machine learning Sasakian and G2 topology on contact Calabi-Yau 7-manifolds
, Physics Letters B, Vol: 850, Pages: 138517-138517, ISSN: 0370-2693 -
Journal articleBerglund P, He Y-H, Heyes E, et al., 2024,
New Calabi–Yau manifolds from genetic algorithms
, Physics Letters B, Vol: 850, Pages: 138504-138504, ISSN: 0370-2693 -
Journal articleCable A, Rajantie A, 2024,
Stochastic parameters for scalar fields in de Sitter spacetime
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleMagueijo J, 2024,
Black holes and foliation-dependent physics
, Physical Review D, Vol: 109, ISSN: 2470-0010In theories where physics depends on a global foliation of space-time, a black hole’s horizon is surrounded by an “eternity skin”: a pile-up of spacelike leaves that in the far-out region cover all times from the start of collapse to future eternity. Any future foliation-dependent change in the laws of physics would be enacted in this region and affect the last stages of collapse toward black hole formation. We show how in some cases the black hole never forms but, rather, bounces into an explosive event. There is also a nonlocal transfer of energy between the asymptotic Universe and the formed black hole precursor, so that the back hole (if formed) or the exploding star (otherwise) will have a different mass from what was initially thrown in. These last matters are generic to nonlocal theories and can be traced to the breakdown of the local Hamiltonian constraint.
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Journal articleBehan C, Chester SM, Ferrero P, 2024,
Gluon scattering in AdS at finite string coupling from localization
, Journal of High Energy Physics, Vol: 2024<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>We consider gluons scattering in Type IIB string theory on AdS<jats:sub>5</jats:sub> × <jats:italic>S</jats:italic> <jats:sup>5</jats:sup> <jats:italic>/</jats:italic>ℤ<jats:sub>2</jats:sub> in the presence of D7 branes, which is dual to the flavor multiplet correlator in a certain 4d <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 USp(2<jats:italic>N</jats:italic>) gauge theory with SO(8) flavor symmetry and complexified coupling <jats:italic>τ</jats:italic>. We compute this holographic correlator in the large <jats:italic>N</jats:italic> and finite <jats:italic>τ</jats:italic> expansion using constraints from derivatives of the mass deformed sphere free energy, which we compute to all orders in 1<jats:italic>/N</jats:italic> and finite <jats:italic>τ</jats:italic> using supersymmetric localization. In particular, we fix the <jats:italic>F</jats:italic> <jats:sup>4</jats:sup> higher derivative correction to gluon scattering on AdS at finite string coupling <jats:italic>τ</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub> = <jats:italic>τ</jats:italic> in terms of Jacobi theta functions, which feature the expected relations between the SL(2<jats:italic>,</jats:italic> ℤ) duality and the SO(8) tria
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Journal articleGenolini PB, Gauntlett JP, Sparks J, 2024,
Equivariant localization for AdS/CFT
, The Journal of High Energy Physics, Vol: 2024, ISSN: 1029-8479We explain how equivariant localization may be applied to AdS/CFT to compute various BPS observables in gravity, such as central charges and conformal dimensions of chiral primary operators, without solving the supergravity equations. The key ingredient is that supersymmetric AdS solutions with an R-symmetry are equipped with a set of equivariantly closed forms. These may in turn be used to impose flux quantization and compute observables for supergravity solutions, using only topological information and the Berline-Vergne-Atiyah-Bott fixed point formula. We illustrate the formalism by considering AdS5 × M6 and AdS3 × M8 solutions of D = 11 supergravity. As well as recovering results for many classes of well-known supergravity solutions, without using any knowledge of their explicit form, we also compute central charges for which explicit supergravity solutions have not been constructed.
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Journal articleAlexandre B, Gielen S, Magueijo J, 2024,
Overall signature of the metric and the cosmological constant
, Journal of Cosmology and Astroparticle Physics, Vol: 2024, ISSN: 1475-7516We consider a little known aspect of signature change, where the overall sign of the metric is allowed to change, with physical implications. We show how, in different formulations of general relativity, this type of classical signature change across boundaries with a degenerate metric can be made consistent with a change in sign (and value) of the cosmological constant Λ. In particular, the separate "mostly plus" and "mostly minus" signature sectors of Lorentzian gravity are most naturally associated with different signs of Λ. We show how this general phenomenon allows for classical solutions where the open dS patch can arise from a portion of AdS space time. These can be interpreted as classical "imaginary space" extensions of the usual Lorentzian theory, with a2 < 0.
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Journal articleRoberts MM, Wiseman T, 2024,
Analog gravity and continuum effective theory of the graphene tight-binding lattice model
, PHYSICAL REVIEW B, Vol: 109, ISSN: 2469-9950 -
Journal articleHo M, Price HCW, Evans TS, et al., 2024,
Dynamics of technology emergence in innovation networks
, Scientific Reports, Vol: 14, ISSN: 2045-2322To create the next innovative product, participants in science need to understand which existing technologies can be combined, what new science must be discovered, and what new technologies must be invented. Knowledge of these often arrives by means of expert consensus or popularity metrics, masking key information on how intellectual efforts accumulate into technological progress. To address this shortcoming, we first present a method to establish a mathematical link between technological evolution and complex networks: a path of events that narrates innovation bottlenecks. Next, we quantify the position and proximity of documents to these innovation paths. The result is an innovation network that more exhaustively captures deterministic knowledge flows with respect to a marketed innovative product. Our dataset, containing over three million biomedical citations, demonstrates the possibility of quantifying the accumulation, speed, and division of labour in innovation over a sixty-year time horizon. The significance of this study includes the (i) use of a purpose-generated dataset showing causal paths from research to development to product; (ii) analysis of the innovation process as a directed acyclic graph; (iii) comparison between calendar time and network time; (iv) ordering of science funders along technology lifecycles; (v) quantification of innovative activities' importance to an innovative outcome; and (vi) integration of publication, patent, clinical trial, regulatory data to study innovation holistically.
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Journal articleBassani PM, Magueijo J, 2024,
Unimodular-like times, evolution and Brans–Dicke gravity
, International Journal of Modern Physics D: Gravitation, Astrophysics and Cosmology, Vol: 33, ISSN: 0218-2718In unimodular-like theories, the constants of nature are demoted from pre-given parameters to phase space variables. Their canonical duals provide physical time variables. We investigate how this interacts with an alternative approach to varying constants, where they are replaced by dynamical scalar fields. Specifically, we investigate the Brans–Dicke theory of gravity and its interaction with clocks dual to the cosmological constant, the Planck mass, etc. We crucially distinguish between the different role of Newton’s G in this process, leading to the possibility of local Lorentz invariance violation. A large number of possible theories emerge, for example where the Brans–Dicke coupling, ω, depends on unimodular-like times (in a generalization of scalar-tensor theories), or even become the dual variable to unimodular-like clocks ticking variations in other demoted constants, such as the cosmological constant. We scan the space of possible theories and select those most interesting regarding the joint variations of the Brans–Dicke ω and other parameters, (such as the cosmological constant); and also regarding their energy conservation violation properties. This ground work is meant to provide the formalism for further developments, namely regarding cosmology, black holes and the cosmological constant problem.
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Conference paperRedmond SF, Benton SJ, Damaren CJ, et al., 2024,
To the stratosphere and beyond! Super-pressure balloon flight overview for the Super-pressure Balloon-borne Imaging Telescope (SuperBIT)
, ISSN: 0277-786XThe Super-pressure Balloon-borne Imaging Telescope (SuperBIT) was a diffraction limited 0.5 m optical-to-near-UV telescope that was designed to study dark matter via cluster weak lensing. SuperBIT launched from Wanaka, New Zealand via NASA's super-pressure balloon (SPB) technology on April 16, 2023 and remained in the stratosphere for 40 days. During the flight, SuperBIT obtained multi-band images for 30 science targets; data analysis to produce shear measurements for each target is ongoing. SuperBIT's pointing system comprised three nested frames that stablized the entire telescope within 0.34 arcseconds rms, plus a back-end tip-tilt mirror that achieved focal plane image stability of 0.055 arcseconds rms during 300 second exposures. The power system reached full charge every day and never dropped below 30% at night. All components remained within their temperature limits, and actively controlled components remained within a standard deviation of ∼0.1 K of their set point. In this paper we provide an overview of the flight trajectory behaviour and flight operations. The first two days of the flight were used for payload characterization and telescope alignment after which all night time was dedicated to science observations. Target scheduling was performed by an on-board “Autopilot” system which tracked available targets and prioritized completing targets over starting new targets. SuperBIT was the first balloon telescope to fly a Starlink dish to enable high-bandwidth communications with the payload. Prior to flight termination, two Data Retrieval System modules were deployed to provide a redundant data recovery method.
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Bookde Rham C, 2024,
The Beauty of Falling: A Life in Pursuit of Gravity
Claudia de Rham has been playing with gravity her entire life. As a diver, experimenting with her body's buoyancy in the Indian Ocean. As a pilot, soaring over Canadian waterfalls on dark mornings before beginning her daily scientific research. As an astronaut candidate, dreaming of the experience of flying free from Earth's pull. And as a physicist, discovering new sides to gravity's irresistible personality by exploring the limits of Einstein's general theory of relativity. In The Beauty of Falling, de Rham shares captivating stories about her quest to gain intimacy with gravity, to understand both its feeling and fundamental nature. Her life's pursuit led her from a twist of fate that snatched away her dream of becoming an astronaut to an exhilarating breakthrough at the very frontiers of gravitational physics. While many of us presume to know gravity quite well, the brightest scientists in history have yet to fully answer the simple question: what exactly is gravity? De Rham reveals how great minds-from Newton and Einstein to Stephen Hawking, Andrea Ghez, and Roger Penrose-led her to the edge of knowledge about this fundamental force. She found hints of a hidden side to gravity at the particle level where Einstein's theory breaks down, leading her to develop a new theory of "massive gravity." De Rham shares how her life's path turned from a precipitous fall to an exquisite flight toward the discovery of something entirely new about our surprising, gravity-driven universe.
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Conference paperVoyer P, Benton SJ, Damaren CJ, et al., 2024,
From SuperBIT to GigaBIT: Informing next-generation balloon-borne telescope design with Fine Guidance System flight data
, ISSN: 0277-786XThe Super-pressure Balloon-borne Imaging Telescope (SuperBIT) is a near-diffraction-limited 0.5 m telescope that launched via NASA's super-pressure balloon technology on April 16, 2023. SuperBIT achieved precise pointing control through the use of three nested frames in conjunction with an optical Fine Guidance System (FGS), resulting in an average image stability of 0.055” over 300-second exposures. The SuperBIT FGS includes a tip-tilt fast-steering mirror that corrects for jitter on a pair of focal plane star cameras. In this paper, we leverage the empirical data from SuperBIT's successful 45-night stratospheric mission to inform the FGS design for the next-generation balloon-borne telescope. The Gigapixel Balloon-borne Imaging Telescope (GigaBIT) is designed to be a 1.35m wide-field, high resolution imaging telescope, with specifications to extend the scale and capabilities beyond those of its predecessor SuperBIT. A description and analysis of the SuperBIT FGS will be presented along with methodologies for extrapolating this data to enhance GigaBIT's FGS design and fine pointing control algorithm. We employ a systems engineering approach to outline and formalize the design constraints and specifications for GigaBIT's FGS. GigaBIT, building on the SuperBIT legacy, is set to enhance high-resolution astronomical imaging, marking a significant advancement in the field of balloon-borne telescopes.
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Journal articleBeccaria M, Giombi S, Tseytlin AA, 2024,
(2,0) theory on S5 x S1 and quantum M2 branes
, NUCLEAR PHYSICS B, Vol: 998, ISSN: 0550-3213 -
Conference paperShaw EC, Ade PAR, Akers S, et al., 2024,
In-Flight Performance of SPIDER's 280 GHz Receivers
, Conference on Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XII, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X -
Journal articleButterfield J, Dowker F, 2024,
Recovering general relativity from a Planck scale discrete theory of quantum gravity
, Philosophy of Physics, Vol: 2, ISSN: 2753-5908An argument is presented that if a theory of quantum gravity is physically discrete at the Planck scale and the theory recovers General Relativity as an approximation, then, at the current stage of our knowledge, causal sets must arise within the theory, even if they are not its basis.We lay out this argument in two claims. Roughly speaking, the first claim is that causal sets can recover continuum Lorentzian manifolds; and the second claim is that no other proposal for a set of discrete data that conforms to our sense of “fundamental discreteness at the Planck scale” is known to be able to recover continuum Lorentzian manifolds. To support this second claim, we show, in particular, that an apparent alternative discrete data set to causal sets, viz., a certain sort of combinatorial Lorentzian simplicial complex, cannot recover General Relativistic spacetimes in the appropriately unique way; for it cannot discriminate between Minkowski spacetime and a spacetime with a certain sort of gravitational wave burst.
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Journal articleChester SM, 2023,
Weizmann lectures on the numerical conformal bootstrap
, Physics Reports, Vol: 1045, Pages: 1-44, ISSN: 0370-1573These lectures were given at the Weizmann Institute in the spring of 2019. They are intended to familiarize students with the nuts and bolts of the numerical bootstrap as efficiently as possible. After a brief review of the basics of conformal field theory in d>2 spacetime dimensions, we discuss how to compute conformal blocks, formulate the crossing equations as a semi-definite programming problem, solve this problem using SDPB on a personal computer, and interpret the results. We include worked examples for all steps, including bounds for 3d CFTs with Z<inf>2</inf> or O(N) global symmetries. Each lecture includes a problem set, which culminate in a precise computation of the 3d Ising model critical exponents using the mixed correlator Z<inf>2</inf> bootstrap. A Mathematica file is included that transforms crossing equations into the proper input form for SDPB.
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Journal articleJazayeri S, Renaux-Petel S, Tong X, et al., 2023,
Parity violation from emergent nonlocality during inflation
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 108, ISSN: 1550-2368Parity violation in the early Universe holds great promise for uncovering new physics. In particular, the primordial scalar four-point correlation function is allowed to develop a parity-violating component when massive spinning particles coupled to a helical chemical potential are present during inflation. In this paper, we explore the rich physics of such a parity-violating trispectrum in the presence of a reduced speed of sound for the Goldstone boson of broken time translations. We show that this signal can be significantly large while remaining under perturbative control, offering promising observational prospects for future cosmological surveys. In the limit of a reduced sound speed, the dynamics admits an effective nonlocal description organized as a time-derivative expansion. This reveals that parity violation arises due to emergent nonlocality in the single-field effective theory. At leading order, this effective theory yields a compact trispectrum template, written in terms of elementary functions. We then conduct a comprehensive analysis of the kinematic dependence of this parity-violating trispectrum and reveal new features. In addition to the low-speed collider resonance, we find a new class of signals lying in the internal soft-limit of the correlator. This signal is characterized by an oscillatory pattern periodic in the momentum ratio, with a frequency determined by the speed of sound and the chemical potential, making it drastically distinct from the conventional cosmological collider signal.
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Conference paperGheorghiade P, Price H, Rivers R, 2023,
The importance of geography to the networked Late Bronze Age Aegean
, Socio-Environmental Dynamics over tha last 15,000 years: The Creation of Landscapes VI, ISSN: 2590-1222 -
Journal articleDowker F, Sorkin RD, 2023,
An intrinsic causality principle in histories-based quantum theory: a proposal
, Journal of Physics A: Mathematical and Theoretical, Vol: 56, ISSN: 1751-8113Relativistic causality (RC) is the principle that no cause can act outside its future light cone, but any attempt to formulate this principle more precisely will depend on the foundational framework that one adopts for quantum theory. Adopting a histories-based (or 'path integral') framework, we relate RC to a condition we term 'Persistence of Zero' (PoZ), according to which an event E of measure zero remains forbidden if one forms its conjunction with any other event associated to a spacetime region that is later than or spacelike to that of E. We also relate PoZ to the Bell inequalities by showing that, in combination with a second, more technical condition it leads to the quantal counterpart of Fine's patching theorem in much the same way as Bell's condition of local causality leads to Fine's original theorem. We then argue that RC per se has very little to say on the matter of which correlations can occur in nature and which cannot. From the point of view we arrive at, histories-based quantum theories are nonlocal in spacetime, and fully in compliance with RC.
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Journal articleMentasti G, Contaldi CR, Peloso M, 2023,
Intrinsic limits on the detection of the anisotropies of the stochastic gravitational wave background
, Physical Review Letters, Vol: 131, ISSN: 0031-9007For any given network of detectors, and for any given integration time, even in the idealized limit of negligible instrumental noise, the intrinsic time variation of the isotropic component of the stochastic gravitational wave background (SGWB) induces a limit on how accurately the anisotropies in the SGWB can be measured. We show here how this sample limit can be calculated and apply this to three separate configurations of ground-based detectors placed at existing and planned sites. Our results show that in the idealized, best-case scenario, individual multipoles of the anisotropies at ℓ≤8 can only be measured to ∼10^{-5}-10^{-4} level over five years of observation as a fraction of the isotropic component. As the sensitivity improves as the square root of the observation time, this poses a very serious challenge for measuring the anisotropies of SGWB of cosmological origin, even in the case of idealized detectors with arbitrarily low instrumental noise.
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Journal articleSeibold FK, Tseytlin AA, 2023,
S-matrix on effective string and compactified membrane
, JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, Vol: 56, ISSN: 1751-8113 -
Journal articleJazayeri S, Renaux-Petel S, Werth D, 2023,
Shapes of the cosmological low-speed collider
, Journal of Cosmology and Astroparticle Physics, Vol: dec 2023, ISSN: 1475-7516Massive particles produced during inflation leave specific signatures in soft limits of correlation functions of primordial fluctuations. When the Goldstone boson of broken time translations acquires a reduced speed of sound, implying that de Sitter boosts are strongly broken, we introduce a novel discovery channel to detect new physics during inflation, called the cosmological low-speed collider signal. This signal is characterised by a distinctive resonance lying in mildly-soft kinematic configurations of cosmological correlators, indicating the presence of a heavy particle, whose position enables to reconstruct its mass. We show that this resonance can be understood in terms of a non-local single-field effective field theory, in which the heavy field becomes effectively non-dynamical. This theory accurately describes the full dynamics of the Goldstone boson and captures all multi-field physical effects distinct from the non-perturbative particle production leading to the conventional cosmological collider signal. As such, this theory provides a systematic and tractable way to study the imprint of massive fields on cosmological correlators. We conduct a thorough study of the low-speed collider phenomenology in the scalar bispectrum, showing that large non-Gaussianities with new shapes can be generated, in particular beyond weak mixing. We also provide a low-speed collider template for future cosmological surveys.
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