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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 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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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 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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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 articleTseytlin AA, 2023,
Comments on a 4-derivative scalar theory in 4 dimensions
, Theoretical and Mathematical Physics, Vol: 217, Pages: 1969-1986, ISSN: 0040-5779We review and elaborate on some aspects of the classically scale-invariant renormalizable 4-derivative scalartheory L = φ ∂4φ + g(∂φ)4. Similar models appear, e.g., in the context of conformal supergravity or inthe description of the crystalline phase of membranes. Considering this theory in Minkowski signature, wesuggest how to define Poincar´e-invariant scattering amplitudes by assuming that only massless oscillating(nongrowing) modes appear as external states. In such shift-symmetric interacting theory, there are no IRdivergences despite the presence of 1/q4 internal propagators. We discuss how nonunitarity of this theorymanifests itself at the level of the one-loop massless scattering amplitude.
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Journal articleTseytlin AA, 2023,
Quantum supermembranes and AdS/CFT duality
, Journal of Experimental and Theoretical Physics, Vol: 137, Pages: 846-863, ISSN: 1063-7761We review and extend some recent work on testing AdS/CFT correspondence between U(N)k × U(N)–k Chern-Simons-matter 3d gauge theory and M-theory in AdS4 × S7/Zk background. We demonstrate that 1-loop term in the quantum M2 brane partition function expanded near a classical solution correctly matches localization predictions on the gauge theory side in the case of BPS Wilson loop expectation value and instanton corrections to free energy.
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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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Journal articleJazayeri S, Renaux-Petel S, 2023,
Cosmological bootstrap in slow motion
, The Journal of High Energy Physics, Vol: 2022, ISSN: 1029-8479Speed matters. How the masses and spins of new particles active during inflation can be read off from the statistical properties of primordial density fluctuations is well understood. However, not when the propagation speeds of the new degrees of freedom and of the curvature perturbation differ, which is the generic situation in the effective field theory of inflationary fluctuations. Here we use bootstrap techniques to find exact analytical solutions for primordial 2-,3- and 4-point correlators in this context. We focus on the imprints of a heavy relativistic scalar coupled to the curvature perturbation that propagates with a reduced speed of sound cs, hence strongly breaking de Sitter boosts. We show that akin to the de Sitter invariant setup, primordial correlation functions can be deduced by acting with suitable weight-shifting operators on the four-point function of a conformally coupled field induced by the exchange of the massive scalar. However, this procedure requires the analytical continuation of this seed correlator beyond the physical domain implied by momentum conservation. We bootstrap this seed correlator in the extended domain from first principles, starting from the boundary equation that it satisfies due to locality. We further impose unitarity, reflected in cosmological cutting rules, and analyticity, by demanding regularity in the collinear limit of the four-point configuration, in order to find the unique solution. Equipped with this, we unveil that heavy particles that are lighter than H/cs leave smoking gun imprints in the bispectrum in the form of resonances in the squeezed limit, a phenomenon that we call the low speed collider. We characterise the overall shape of the signal as well as its unusual logarithmic mass dependence, both vividly distinct from previously identified signatures of heavy fields. Eventually, we demonstrate that these features can be understood in a simplified picture in which the heavy field is integrated out, albeit
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Journal articleGheorghiade P, Vasiliauskaite V, Diachenko A, et al., 2023,
Entropology: an information-theoretic approach to understanding archaeological data
, Journal of Archaeological Method and Theory, Vol: 30, Pages: 1109-1141, ISSN: 1072-5369The main objective of this paper is to develop quantitative measures for describing the diversity, homogeneity, and similarity of archaeological data. It presents new approaches to characterize the relationship between archaeological assemblages by utilizing entropy and its related attributes, primarily diversity, and by drawing inspiration from ecology. Our starting premise is that diachronic changes in our data provide a distorted reflection of social processes and that spatial differences in data indicate cultural distancing. To investigate this premise, we adopt a parsimonious approach for comparing assemblage profiles employing and comparing a range of (Hill) diversities, which enable us to exploit different aspects of the data. The modelling is tested on two seemingly large datasets: a Late Bronze Age Cretan dataset with circa 13,700 entries (compiled by PG); and a 4th millennium Western Tripolye dataset with circa 25,000 entries (compiled by AD). The contrast between the strongly geographically and culturally heterogeneous Bronze Age Crete and the strongly homogeneous Western Tripolye culture in the Southern Bug and Dnieper interfluve show the successes and limitations of our approach. Despite the seemingly large size of our datasets, these data highlight limitations that confine their utility to non-semantic analysis. This requires us to consider different ways of treating and aggregating assemblages, either as censuses or samples, contingent upon the degree of representativeness of the data. While our premise, that changes in data reflect societal changes, is supported, it is not definitively confirmed. Consequently, this paper also exemplifies the limitations of large archaeological datasets for such analyses.
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Journal articleDiachenko A, Rivers RJ, Sobkowiak-Tabaka I, 2023,
Convergent evolution of prehistoric technologies: the entropy and diversity of limited solutions
, Journal of Archaeological Method and Theory, Vol: 30, Pages: 1168-1199, ISSN: 1072-5369Linking the likelihood of convergent evolution to the technologies’ complexity, this paper identifies the scales of technological diffusion and convergence, i.e., the evolving of structures that are similar, but not related to a common “ancestor.” Our study provides quantitative measures for understanding complexity and connectivity in technologies. The utility of our approach is exemplified through the case study of Cucuteni-Tripolye pottery kilns in Chalcolithic Southeastern Europe. The analysis shows that technological evolution has to be scaled to the “technologically important” (in quantitative terms) component parts, whose introduction shapes a ground for extinction and self-evolvement caused by the cascade effects along technological design structure. Similar technological solutions to the technological design structure engender the spread of similar devices in various locations. Surprisingly, such a broad distribution may be the result of relatively low internal diversity, rather than arising from higher efficiency. This gives some reasons for the underestimation of convergence as a mechanism for evolution of technology in current prehistoric archaeology.
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Book, 2023,
Encyclopedia of Cosmology, The, Set 2: Frontiers in Cosmology (in 3 Volumes)
, ISBN: 9789811289699Together, these volumes will be a comprehensive review of the most important current topics in cosmology, discussing the important concepts and current status in each field, covering both theory and observation.These three volumes are ...
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Book chapterRivers R, Paliou E, Evans T, 2023,
Gravity and Maximum Entropy Models
, The Oxford Handbook of Archaeological Network Research, Editors: Brughmans, Mills, Munson, Peeples, Publisher: Oxford University Press, Pages: 186-199, ISBN: 9780198854265Gravity models are a class of quantitative models that can be used for describing the spatial characteristics of social interactions, providing a realization of Tobler’s “law” of geography that “near things are more related than distant things.” In archaeology, they are particularly suited for describing historic and prehistoric “exchange” and “settlement formation.” Although, quantitatively, they were originally little more than mimicry of Newtonian gravitation, they arise naturally in some forms of economic modeling and as the “most likely” outcomes (MaxEnt) from limited knowledge. We discuss several of their key applications to archaeological data.
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Journal articleMagueijo J, 2023,
Evolving laws and cosmological energy
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 108, ISSN: 1550-2368We couple the issue of evolution in the laws of physics with that of violations of energy conservation. Avoiding a time dependence in terms of coordinate time, we define evolution as a function of time variables canonically dual to “constants” (such as Λ, the Planck mass, or the gravitational coupling), mimicking a procedure associated with one formulation of unimodular gravity. We then introduce variability via a dependence of other fundamental “constants” on these clocks. Although this is not needed, sharper results are obtained if this procedure violates local Lorentz invariance, which we define in the spirit of Horava-Lifshitz theories (modifying a 3+1 split action, so that a Lorentz invariant 4D reassembly is no longer possible). We find that variability in the “laws of physics” generically leads to violations of energy conservation if either a matter parameter varies as a function of a gravitational clock, or a gravity parameter depends on a matter clock, with the other combinations sterile. In general the matter components associated with the varying parameter or the clock absorb or give off the violated energy. We illustrate this with a variety of clocks (ticking unimodular time, Ricci time, etc.) and parameters (mainly the gravitational and matter speed of light, but also Λ). We can accommodate in this construction (and improve on) several early varying speed of light models, allowing for variability effects related to the spatial curvature and Λ to cause creation of radiation and a hot big bang.
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Journal articleBenetti Genolini P, Gauntlett JP, Sparks J, 2023,
Localizing wrapped M5-branes and gravitational blocks
, Physical Review D, Vol: 108, ISSN: 2470-0010We consider d ¼ 2, N ¼ ð0; 2Þ SCFTs that can arise from M5-branes wrapping four-dimensional,complex, toric manifolds and orbifolds. We use equivariant localization to compute the off-shell centralcharge of the dual supergravity solutions, obtaining a result that can be written as a sum of gravitationalblocks and precisely agrees with a field theory computation using anomaly polynomials and cextremization.
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Journal articleSirks EL, Massey R, Gill AS, et al., 2023,
Data Downloaded via Parachute from a NASA Super-Pressure Balloon
, Aerospace, Vol: 10In April 2023, the superBIT telescope was lifted to the Earth’s stratosphere by a helium-filled super-pressure balloon to acquire astronomical imaging from above (99.5% of) the Earth’s atmosphere. It was launched from New Zealand and then, for 40 days, circumnavigated the globe five times at a latitude 40 to 50 degrees south. Attached to the telescope were four “drs” (Data Recovery System) capsules containing 5 TB solid state data storage, plus a gnss receiver, Iridium transmitter, and parachute. Data from the telescope were copied to these, and two were dropped over Argentina. They drifted 61 km horizontally while they descended 32 km, but we predicted their descent vectors within 2.4 km: in this location, the discrepancy appears irreducible below ∼2 km because of high speed, gusty winds and local topography. The capsules then reported their own locations within a few metres. We recovered the capsules and successfully retrieved all of superBIT’s data despite the telescope itself being later destroyed on landing.
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Journal articlede Rham C, Kozuszek J, Tolley AJ, et al., 2023,
Dynamical formulation of ghost-free massive gravity
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleToomey MW, Koushiappas SM, Alexandre B, et al., 2023,
Quantum gravity signatures in the late Universe
, Physical Review D, Vol: 108, ISSN: 2470-0010We calculate deviations in cosmological observables as a function of parameters in a class of connection-based models of quantum gravity. In this theory nontrivial modifications to the background cosmology can occur due to a distortion of the wave function of the Universe at the transition from matter to dark energy domination (which acts as a “reflection” in connection space). We are able to exclude some regions of parameter space and show with projected constraints that future experiments like DESI will be able to further constrain these models. An interesting feature of this theory is that there exists a region of parameter space that could naturally alleviate the S8 tension.
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Journal articleBeccaria M, Giombi S, Tseytlin AA, 2023,
Instanton contributions to the ABJM free energy from quantum M2 branes
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleBoido A, Gauntlett JP, Martelli D, et al., 2023,
Gravitational blocks, spindles and GK geometry
, Communications in Mathematical Physics, Vol: 403, Pages: 917-1003, ISSN: 0010-3616We derive a gravitational block formula for the supersymmetric action for ageneral class of supersymmetric AdS solutions, described by GK geometry. Extremalpoints of this action describe supersymmetric AdS3 solutions of type IIB supergravity,sourced by D3-branes, and supersymmetric AdS2 solutions of D = 11 supergravity,sourced by M2-branes. In both cases, the branes are also wrapped over a two-dimensionalorbifold known as a spindle, or a two-sphere. We develop various geometric methodsfor computing the gravitational block contributions, allowing us to recover previouslyknown results for various explicit supergravity solutions, and to significantly generalizethese results to other compactifications. For the AdS3 solutions we give a general proofthat our off-shell supersymmetric action agrees with an appropriate off-shell c-functionin the dual field theory, establishing a very general exact result in holography. Forthe AdS2 solutions our gravitational block formula allows us to obtain the entropy forsupersymmetric, magnetically charged and accelerating black holes in AdS4.
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Note to staff: Adding new publications to a research group
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