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Journal articleEvnin O, Mkrtchyan K, 2023,
Three approaches to chiral form interactions
, DIFFERENTIAL GEOMETRY AND ITS APPLICATIONS, Vol: 89, ISSN: 0926-2245 -
Journal articleBobev N, Gautason FF, van Muiden J, 2023,
Holographic 3d $$ \mathcal{N} $$ = 1 conformal manifolds
, Journal of High Energy Physics, Vol: 2023<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>We construct and study several examples of continuous families of AdS<jats:sub>4</jats:sub><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> = 1 solutions of four-dimensional maximal gauged supergravity. These backgrounds provide the holographic descriptions of conformal manifolds of the dual 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> = 1 SCFTs. The solutions we study can be uplifted to type IIB supergravity where they arise from D3-branes wrapping an <jats:italic>S</jats:italic><jats:sup>1</jats:sup> with an S-duality twist. We find the spectrum of low lying operators in 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> = 1 SCFTs as a function of the exactly marginal coupling and discuss the structure of the corresponding superconformal multiplets. Using string theory techniques we also study additional examples of continuous families of <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \mathcal{N} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/Mat
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Journal articleAlexandre B, Isichei R, Magueijo J, 2023,
Unitary and Vilenkin's wave functions
, Physical Review D, Vol: 108, ISSN: 2470-0010It is remarkably difficult to reconcile unitarity and Vilenkin’s wave function. For example, the natural conserved inner product found in quantum unimodular gravity applies to the Hartle-Hawking wave function, but fails for its Vilenkin counterpart. We diagnose this failure from different angles (Laplace transform instead of Fourier transform, non-Hermiticity of the Hamiltonian, etc.) to conclude that ultimately it stems from allowing the connection to become imaginary in a section of its contour. In turn this is the unavoidable consequence of representing the Euclidean theory as an imaginary image within a fundamentally Lorentzian theory. It is nonetheless possible to change the underlying theory and replace the connection’s foray into the imaginary axis by an actual signature change (with the connection, action and Hamiltonian remaining real). The structural obstacles to unitarity are then removed, but special care must still be taken, because the Euclidean theory a priori has boundaries, so that appropriate boundary conditions are required for unitarity. Reflecting boundary conditions would reinstate a Hartle-Hawking-like solution in the Lorentzian regime. To exclude an incoming wave in the Lorentzian domain one must allow a semi-infinite tower of spheres in the Euclidean region, wave packets traveling through successive spheres for half an eternity in unimodular time. Such a “Sisyphus” boundary condition no longer even vaguely resembles Vilenkin’s original proposal.
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Journal articleChester SM, Dupuis É, Witczak-Krempa W, 2023,
Evidence for web of dualities from monopole operators
, Physical Review D, Vol: 108, ISSN: 2470-0010We give evidence for the web of 3d bosonization dualities in conformal field theories (CFTs) by computing monopole operator scaling dimensions in (2+1)-dimensional quantum electrodynamics (QED3) with Chern-Simons level k and N complex bosons in a large-N, k expansion. We first consider the k=0 case, where we show that scaling dimensions previously computed to subleading order in 1/N can be extrapolated to N=1 and matched to O(2) Wilson-Fisher CFT scaling dimensions with around 5% error, which is evidence for particle-vortex duality. We then generalize the subleading calculation to large N, k and fixed k/N, extrapolate to N=k=1, and consider monopole operators that are conjectured to be dual to nondegenerate scalar operators in a theory of a single Dirac fermion. We find matches typically with 1% error or less, which is strong evidence of this so-called "seed"duality that implies a web of 3d bosonization dualities among CFTs.
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Journal articleAgazie G, Anumarlapudi A, Archibald AM, et al., 2023,
The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background
, Astrophysical Journal Letters, Vol: 951, ISSN: 2041-8205We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves. The correlations follow the Hellings-Downs pattern expected for a stochastic gravitational-wave background. The presence of such a gravitational-wave background with a power-law spectrum is favored over a model with only independent pulsar noises with a Bayes factor in excess of 10<sup>14</sup>, and this same model is favored over an uncorrelated common power-law spectrum model with Bayes factors of 200-1000, depending on spectral modeling choices. We have built a statistical background distribution for the latter Bayes factors using a method that removes interpulsar correlations from our data set, finding p = 10<sup>−3</sup> (≈3σ) for the observed Bayes factors in the null no-correlation scenario. A frequentist test statistic built directly as a weighted sum of interpulsar correlations yields p = 5 × 10<sup>−5</sup> to 1.9 × 10<sup>−4</sup> (≈3.5σ-4σ). Assuming a fiducial f <sup>−2/3</sup> characteristic strain spectrum, as appropriate for an ensemble of binary supermassive black hole inspirals, the strain amplitude is 2.4 − 0.6 + 0.7 × 10 − 15 (median + 90% credible interval) at a reference frequency of 1 yr<sup>−1</sup>. The inferred gravitational-wave background amplitude and spectrum are consistent with astrophysical expectations for a signal from a population of supermassive black hole binaries, although more exotic cosmological and astrophysical sources cannot be excluded. The observation of Hellings-Downs correlations points to the gravitational-wave origin of this signal.
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Journal articleAgazie G, Alam MF, Anumarlapudi A, et al., 2023,
The NANOGrav 15 yr Data Set: Observations and Timing of 68 Millisecond Pulsars
, Astrophysical Journal Letters, Vol: 951, ISSN: 2041-8205We present observations and timing analyses of 68 millisecond pulsars (MSPs) comprising the 15 yr data set of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). NANOGrav is a pulsar timing array (PTA) experiment that is sensitive to low-frequency gravitational waves (GWs). This is NANOGrav’s fifth public data release, including both “narrowband” and “wideband” time-of-arrival (TOA) measurements and corresponding pulsar timing models. We have added 21 MSPs and extended our timing baselines by 3 yr, now spanning nearly 16 yr for some of our sources. The data were collected using the Arecibo Observatory, the Green Bank Telescope, and the Very Large Array between frequencies of 327 MHz and 3 GHz, with most sources observed approximately monthly. A number of notable methodological and procedural changes were made compared to our previous data sets. These improve the overall quality of the TOA data set and are part of the transition to new pulsar timing and PTA analysis software packages. For the first time, our data products are accompanied by a full suite of software to reproduce data reduction, analysis, and results. Our timing models include a variety of newly detected astrometric and binary pulsar parameters, including several significant improvements to pulsar mass constraints. We find that the time series of 23 pulsars contain detectable levels of red noise, 10 of which are new measurements. In this data set, we find evidence for a stochastic GW background.
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Journal articleAgazie G, Anumarlapudi A, Archibald AM, et al., 2023,
The NANOGrav 15 yr Data Set: Detector Characterization and Noise Budget
, Astrophysical Journal Letters, Vol: 951, ISSN: 2041-8205Pulsar timing arrays (PTAs) are galactic-scale gravitational wave (GW) detectors. Each individual arm, composed of a millisecond pulsar, a radio telescope, and a kiloparsecs-long path, differs in its properties but, in aggregate, can be used to extract low-frequency GW signals. We present a noise and sensitivity analysis to accompany the NANOGrav 15 yr data release and associated papers, along with an in-depth introduction to PTA noise models. As a first step in our analysis, we characterize each individual pulsar data set with three types of white-noise parameters and two red-noise parameters. These parameters, along with the timing model and, particularly, a piecewise-constant model for the time-variable dispersion measure, determine the sensitivity curve over the low-frequency GW band we are searching. We tabulate information for all of the pulsars in this data release and present some representative sensitivity curves. We then combine the individual pulsar sensitivities using a signal-to-noise ratio statistic to calculate the global sensitivity of the PTA to a stochastic background of GWs, obtaining a minimum noise characteristic strain of 7 × 10<sup>−15</sup> at 5 nHz. A power-law-integrated analysis shows rough agreement with the amplitudes recovered in NANOGrav’s 15 yr GW background analysis. While our phenomenological noise model does not model all known physical effects explicitly, it provides an accurate characterization of the noise in the data while preserving sensitivity to multiple classes of GW signals.
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Journal articleAfzal A, Agazie G, Anumarlapudi A, et al., 2023,
The NANOGrav 15yr Data Set: Search for Signals from New Physics
, Astrophysical Journal Letters, Vol: 951, ISSN: 2041-8205The 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence for the presence of a low-frequency gravitational-wave (GW) background. In this paper, we investigate potential cosmological interpretations of this signal, specifically cosmic inflation, scalar-induced GWs, first-order phase transitions, cosmic strings, and domain walls. We find that, with the exception of stable cosmic strings of field theory origin, all these models can reproduce the observed signal. When compared to the standard interpretation in terms of inspiraling supermassive black hole binaries (SMBHBs), many cosmological models seem to provide a better fit resulting in Bayes factors in the range from 10 to 100. However, these results strongly depend on modeling assumptions about the cosmic SMBHB population and, at this stage, should not be regarded as evidence for new physics. Furthermore, we identify excluded parameter regions where the predicted GW signal from cosmological sources significantly exceeds the NANOGrav signal. These parameter constraints are independent of the origin of the NANOGrav signal and illustrate how pulsar timing data provide a new way to constrain the parameter space of these models. Finally, we search for deterministic signals produced by models of ultralight dark matter (ULDM) and dark matter substructures in the Milky Way. We find no evidence for either of these signals and thus report updated constraints on these models. In the case of ULDM, these constraints outperform torsion balance and atomic clock constraints for ULDM coupled to electrons, muons, or gluons.
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Journal articleAgazie G, Anumarlapudi A, Archibald AM, et al., 2023,
The NANOGrav 15 yr Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
, Astrophysical Journal Letters, Vol: 951, ISSN: 2041-8205Evidence for a low-frequency stochastic gravitational-wave background has recently been reported based on analyses of pulsar timing array data. The most likely source of such a background is a population of supermassive black hole binaries, the loudest of which may be individually detected in these data sets. Here we present the search for individual supermassive black hole binaries in the NANOGrav 15 yr data set. We introduce several new techniques, which enhance the efficiency and modeling accuracy of the analysis. The search uncovered weak evidence for two candidate signals, one with a gravitational-wave frequency of ∼4 nHz, and another at ∼170 nHz. The significance of the low-frequency candidate was greatly diminished when Hellings-Downs correlations were included in the background model. The high-frequency candidate was discounted due to the lack of a plausible host galaxy, the unlikely astrophysical prior odds of finding such a source, and since most of its support comes from a single pulsar with a commensurate binary period. Finding no compelling evidence for signals from individual binary systems, we place upper limits on the strain amplitude of gravitational waves emitted by such systems. At our most sensitive frequency of 6 nHz, we place a sky-averaged 95% upper limit of 8 × 10<sup>−15</sup> on the strain amplitude. We also calculate an exclusion volume and a corresponding effective radius, within which we can rule out the presence of black hole binaries emitting at a given frequency.
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Journal articlede Rham C, Garcia-Saenz S, Heisenberg L, et al., 2023,
To half-be or not to be?
, The Journal of High Energy Physics, Vol: 2023, Pages: 1-31, ISSN: 1029-8479It has recently been argued that half degrees of freedom could emerge in Lorentz and parity invariant field theories, using a non-linear Proca field theory dubbed Proca-Nuevo as a specific example. We provide two proofs, using the Lagrangian and Hamiltonian pictures, that the theory possesses a pair of second class constraints, leaving D − 1 degrees of freedom in D spacetime dimensions, as befits a consistent Proca model. Our proofs are explicit and straightforward in two dimensions and we discuss how they generalize to an arbitrary number of dimensions. We also clarify why local Lorentz and parity invariant field theories cannot hold half degrees of freedom.
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Journal articleBeccaria M, Korchemsky GP, Tseytlin AA, 2023,
Non-planar corrections in orbifold/orientifold <i>N</i>=2 superconformal theories from localization
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Cite
- Citations: 14
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Journal articleGiombi S, Tseytlin AA, 2023,
Wilson Loops at Large N and the Quantum M2-Brane
, PHYSICAL REVIEW LETTERS, Vol: 130, ISSN: 0031-9007- Cite
- Citations: 19
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Journal articleCamargo-Molina JE, Rajantie A, 2023,
Phase transitions in de Sitter spacetimes: the stochastic formalism
, Physical Review D, Vol: 107, ISSN: 2470-0010The stochastic spectral expansion method offers a simple framework for calculations in de Sitter spacetimes. We show how to extend its reach to metastable vacuum states, both in the case when the potential is bounded from below, and when it is unbounded from below and therefore no stable vacuum state exists. In both cases, the decay rate of the metastable vacuum is given by the lowest nonzero eigenvalue associated to the Fokker–Planck equation. We show how the corresponding eigenfunction determines the field probability distribution which can be used to compute correlation functions and other observables in the metastable vacuum state.
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Journal articleMitridate A, Trickle T, Zhang Z, et al., 2023,
Snowmass white paper: Light dark matter direct detection at the interface with condensed matter physics
, Physics of the Dark Universe, Vol: 40, ISSN: 2212-6864Direct detection experiments for light (sub-GeV) dark matter are making enormous leaps in reaching previously unexplored theory space. The need for accurate characterizations of target responses has led to a growing interplay between particle and condensed matter physics. This white paper summarizes recent progress on direct detection calculations that utilize state-of-the-art numerical tools in condensed matter physics and effective field theory techniques. These new results provide the theoretical framework for interpreting ongoing and planned experiments using electronic and collective excitations, and for optimizing future searches.
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Journal articleDunning J, Burke T, Chan AHH, et al., 2023,
Opposite-sex associations are linked with annual fitness, but sociality is stable over lifetime
, Behavioral Ecology, Vol: 315, Pages: 315-324, ISSN: 1045-2249Animal sociality, an individual’s propensity to associate with others, has fitness consequences through mate choice, for example, directly, by increasing the pool of prospective partners, and indirectly through increased survival, and individuals benefit from both. Annually, fitness consequences are realized through increased mating success and subsequent fecundity. However, it remains unknown whether these consequences translate to lifetime fitness. Here, we quantified social associations and their link to fitness annually and over lifetime, using a multi-generational, genetic pedigree. We used social network analysis to calculate variables representing different aspects of an individual’s sociality. Sociality showed high within-individual repeatability. We found that birds with more opposite-sex associates had higher annual fitness than those with fewer, but this did not translate to lifetime fitness. Instead, for lifetime fitness, we found evidence for stabilizing selection on opposite-sex sociality, and sociality in general, suggesting that reported benefits are only short-lived in a wild population, and that selection favors an average sociality.
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Journal articleMawby C, Halliwell JJ, 2023,
Leggett-Garg violations for continuous-variable systems with Gaussian states
, PHYSICAL REVIEW A, Vol: 107, ISSN: 2469-9926- Cite
- Citations: 6
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Journal articleGledhill K, Hanany A, 2023,
Poisson brackets for some Coulomb branches
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Cite
- Citations: 3
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Journal articleAlexandre B, Magueijo J, 2023,
Unimodular Hartle-Hawking wave packets and their probability interpretation
, Physical Review D, Vol: 107, ISSN: 2470-0010We reexamine the Hartle-Hawking wave function from the point of view of a quantum theory whichstarts from the connection representation and allows for off-shell nonconstancy of Λ (as in unimodulartheory), with a concomitant dual relational time variable. By translating its structures to the metricrepresentation we find a nontrivial inner product rendering wave packets of Hartle-Hawking wavesnormalizable and the time evolution unitary; however, the implied probability measure differssignificantly from the naive jψj2. In contrast with the (monochromatic) Hartle-Hawking wave function,these packets form traveling waves with a probability peak describing de Sitter space, except near thebounce, where the incident and reflected waves interfere, transiently recreating the usual standing wave.Away from the bounce the packets get sharper both in metric and connection space, an apparentcontradiction with Heisenberg’s principle allowed by the fact that the metric is not Hermitian, eventhough its eigenvalues are real. Near the bounce, the evanescent wave not only penetrates into theclassically forbidden region but also extends into the a2 < 0 Euclidean domain. We work out thepropagators for this theory and relate them to the standard ones. The a ¼ 0 point (aka the “nothing”) isunremarkable, and in any case a wave function peaked therein is typically non-normalizable and/orimplies a nonsensical probability for Λ (which the Universe would preserve forever). Within this theory itmakes more sense to adopt a Gaussian state in an appropriate function of Λ, and use the probabilityassociated with the evanescent wave present near the time of the bounce as a measure of the likelihood ofcreation of a pair of time-symmetric semiclassical Universes.
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Journal articleMkrtchyan K, Valach F, 2023,
Democratic actions for type II supergravities
, PHYSICAL REVIEW D, Vol: 107, ISSN: 2470-0010- Cite
- Citations: 8
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Journal articleDe Biasio D, Freigang J, Luest D, et al., 2023,
Gradient flow of Einstein-Maxwell theory and Reissner-Nordstrom black holes
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479- Cite
- Citations: 5
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Journal articleBoido A, Gauntlett JP, Martelli D, et al., 2023,
Entropy functions for accelerating black holes
, Physical Review Letters, Vol: 130, ISSN: 0031-9007We introduce an entropy function for supersymmetric accelerating black holes in four-dimensional anti–de Sitter space that uplift on general Sasaki-Einstein manifolds X7 to solutions of M theory. This allows oneto compute the black hole entropy without knowing the explicit solutions. A dual holographic microstatecounting would follow from computing certain supersymmetric partition functions of Chern-Simonsmatter theories compactified on a spindle. We make a general prediction for a class of such partitionfunctions in terms of “blocks,” with each block being constructed from the partition function on a threesphere
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Journal articleAharony O, Chester SM, Sheaffer T, et al., 2023,
Explicit holography for vector models at finite N, volume and temperature
, Journal of High Energy Physics, Vol: 2023<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>In previous work we constructed an explicit mapping between large <jats:italic>N</jats:italic> vector models (free or critical) in <jats:italic>d</jats:italic> dimensions and a non-local high-spin gravity theory on <jats:italic>AdS</jats:italic><jats:sub><jats:italic>d</jats:italic>+1</jats:sub>, such that the gravitational theory reproduces the field theory correlation functions order by order in 1<jats:italic>/N</jats:italic>. In this paper we discuss three aspects of this mapping. First, our original mapping was not valid non-perturbatively in 1<jats:italic>/N</jats:italic>, since it did not include non- local correlations between the gravity fields which appear at finite <jats:italic>N</jats:italic>. We show that by using a bi-local <jats:italic>G</jats:italic> − Σ type formalism similar to the one used in the SYK model, we can construct an exact mapping to the bulk that is valid also at finite <jats:italic>N</jats:italic>. The theory in the bulk contains additional auxiliary fields which implement the finite <jats:italic>N</jats:italic> constraints. Second, we discuss the generalization of our mapping to the field theory on <jats:italic>S</jats:italic><jats:sup><jats:italic>d</jats:italic></jats:sup>, and in particular how the sphere free energy matches exactly between the two sides, and how the mapping can be consistently regularized. Finally, we discuss the field theory at finite temperature, and show that the low-temperature phase of the vector models can be mapped to a high-spin gravity theory on thermal AdS space.</jats:p>
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Journal articleDavies J, Hughes D, Rosenthal M, et al., 2023,
An invisible threat? Aspergillus positive cultures and co-infecting bacteria in airway sample
, Journal of Cystic Fibrosis, Vol: 22, Pages: 320-326, ISSN: 1569-1993BackgroundAspergillus fumigatus (Af) infection is associated with poor lung health in chronic suppurative lung diseases but often goes undetected. We hypothesised that inhibition of Af growth by Pseudomonas aeruginosa (Pa) increases the frequency of false-negative Af culture in co-infected people. Using a substantial group of cystic fibrosis (CF) airway samples, we assessed the relationship between Af and bacterial pathogens, additionally comparing fungal culture with next-generation sequencing.MethodsFrequency of co-culture was assessed for 44,554 sputum/BAL cultures, from 1,367 CF patients between the years 2010–2020. In a subgroup, Internal Transcribed Spacer-2 (ITS2) fungal sequencing was used to determine sequencing-positive, culture-negative (S+/C-) rates.ResultsPa+ samples were nearly 40% less likely (P<0.0001) than Pa- samples to culture Af, an effect that was also seen with some other Gram-negative isolates. This impact varied with Pa density and appeared to be moderated by Staphylococcus aureus co-infection. Sequencing identified Af-S+/C- for 40.1% of tested sputa. Samples with Pa had higher rates of Af-S+/C- (49.3%) than those without (35.7%; RR 1.38 [1.02–1.93], P<0.05). Af-S+/C- rate was not changed by other common bacterial infections. Pa did not affect the S+/C- rates of Candida, Exophiala or Scedosporium.ConclusionsPa/ Af co-positive cultures are less common than expected in CF. Our findings suggest an Af-positive culture is less likely in the presence of Pa. Interpretation of negative cultures should be cautious, particularly in Pa-positive samples, and a companion molecular diagnostic could be useful. Further work investigating mechanisms, alternative detection techniques and other chronic suppurative lung diseases is needed.
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Journal articleBaker T, Barausse E, Chen A, et al., 2023,
Testing gravitational wave propagation with multiband detections
, Journal of Cosmology and Astroparticle Physics, Vol: 2023, Pages: 1-21, ISSN: 1475-7516Effective field theories (EFT) of dark energy (DE) — built to parameterise the properties of DE in an agnostic manner — are severely constrained by measurements of the propagation speed of gravitational waves (GW). However, GW frequencies probed by ground-based interferometers lie around the typical strong coupling scale of the EFT, and it is likely that the effective description breaks down before even reaching that scale. We discuss how this leaves the possibility that an appropriate ultraviolet completion of DE scenarios, valid at scales beyond an EFT description, can avoid present constraints on the GW speed. Instead, additional constraints in the lower frequency LISA band would be harder to escape, since the energies involved are orders of magnitude lower. By implementing a method based on GW multiband detections, we show indeed that a single joint observation of a GW150914-like event by LISA and a terrestrial interferometer would allow one to constrain the speed of light and gravitons to match to within 10-15. Multiband GW observations can therefore firmly constrain scenarios based on the EFT of DE, in a robust and unambiguous way.
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Journal articleGielen S, Magueijo J, 2023,
Quantum resolution of the cosmological singularity without new physics
, EPL, Vol: 141, ISSN: 0302-072XWe study a quantum Hot Big Bang in the connection representation, with a matter constant of motion m whose conjugate defines time. Superpositions in m induce a unitary inner product. The wave function reveals a resolution of the singularity problem without new physics or supplementary boundary conditions. Backtracking in time, the probability peak eventually halts at a maximum curvature, its height dropping thereafter while a symmetric contracting peak rises. The Big Bang is replaced by a superposition of contracting and expanding regular Universes. We contrast these findings with the situation in the metric representation, where boundary conditions at the singularity are needed for unitary evolution.
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Journal articleCabass G, Jazayeri S, Pajer E, et al., 2023,
Parity violation in the scalar trispectrum: no-go theorems and yes-go examples
, The Journal of High Energy Physics, Vol: 2023, ISSN: 1029-8479We derive a set of no-go theorems and yes-go examples for the parity-odd primordial trispectrum of curvature perturbations. We work at tree-level in the decoupling limit of the Effective Field Theory of Inflation and assume scale invariance and a Bunch-Davies vacuum. We show that the parity-odd scalar trispectrum vanishes in the presence of any number of scalar fields with arbitrary mass and any parity-odd scalar correlator vanishes in the presence of any number of spinning fields with massless de Sitter mode functions, in agreement with the findings of Liu, Tong, Wang and Xianyu [1]. The same is true for correlators with an odd number of conformally-coupled external fields. We derive these results using both the (boostless) cosmological bootstrap, in particular the Cosmological Optical Theorem, and explicit perturbative calculations. We then discuss a series of yes-go examples by relaxing the above assumptions one at the time. In particular, we provide explicit results for the parity-odd trispectrum for (i) violations of scale invariance in single-clock inflation, (ii) the modified dispersion relation of the ghost condensate (non-Bunch-Davies vacuum), and (iii) interactions with massive spinning fields. Our results establish the parity-odd trispectrum as an exceptionally sensitive probe of new physics beyond vanilla inflation.
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Journal articleIsichei R, Magueijo J, 2023,
Minisuperspace quantum cosmology from the Einstein-Cartan path integral
, Physical Review D, Vol: 107, Pages: 1-8, ISSN: 2470-0010We derive the fixed-Λ and unimodular propagators using the path integral formalism as applied to the Einstein-Cartan action. The simplicity of the action (which is linear in the lapse function) allows for an exact integration starting from the lapse function and the enforcement of the Hamiltonian constraint, leading to a product of Chern-Simons states if the connection is fixed at the endpoints. No saddle point approximation is needed. Should the metric be fixed at the endpoints, then, depending on the contour chosen for the connection, Hartle-Hawking or Vilenkin propagators are obtained. Thus, in this approach one trades a choice of contour in the lapse function for one in the connection, where appropriate. The unimodular propagators are also trivial to obtain via the path integral, and the previously derived expressions are recovered.
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Journal articleChester SM, 2023,
Bootstrapping 4d $$ \mathcal{N} $$ = 2 gauge theories: the case of SQCD
, Journal of High Energy Physics, Vol: 2023<jats:title> A <jats:sc>bstract</jats:sc> </jats:title> <jats:p> We derive exact relations between certain integrals of the conserved flavor current four point function in 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 conformal field theories (CFTs) and derivatives of the mass deformed sphere free energy, which can be computed exactly for gauge theories using supersymmetric localization. For conformal gauge theories with flavor groups of rank greater than one, there are at least two such integrated constraints, which can then be combined with the numerical conformal bootstrap to bound CFT data as a function of the complexified gauge coupling <jats:italic>τ</jats:italic> . We apply this strategy to the case of SU(2) conformal SQCD with flavor group SO(8), where we compute bounds on unprotected scaling dimensions as a function of <jats:italic>τ</jats:italic> that match the free theory limit, and exhibit the expected mixing between the action of the SL(2 <jats:italic>,</jats:italic> ℤ) duality group and SO(8) triality. </jats:p>
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Journal articleGielen S, Magueijo J, 2023,
Quantum analysis of the recent cosmological bounce in the comoving Hubble length
, Physical Review D, Vol: 107, Pages: 1-16, ISSN: 2470-0010We formulate the transition from decelerated to accelerated expansion as a bounce in connection space and study its quantum cosmology, knowing that reflections are notorious for bringing quantum effects to the fore. We use a formalism for obtaining a time variable via the demotion of the constants of nature to integration constants, and focus on a toy universe containing only radiation and a cosmological constant Λ for simplicity. We find that, beside the usual factor-ordering ambiguities, there is an ambiguity in the order of the quantum equation, leading to two distinct theories: one second order, and one first order. In both cases two time variables may be defined, conjugate to Λ and the radiation constant of motion. We make little headway with the second-order theory, but are able to produce solutions to the first-order theory. They exhibit the well-known “ringing” whereby incident and reflected waves interfere, leading to oscillations in the probability distribution even for well-peaked wave packets. We also examine in detail the probability measure within the semiclassical approximation. Close to the bounce, the probability distribution becomes double peaked, with one peak following a trajectory close to the classical limit but with a Hubble parameter slightly shifted downwards, and the other with a value of b stuck at its minimum. An examination of the effects still closer to the bounce, and within a more realistic model involving matter and Λ, is left to future work.
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Journal articleBeccaria M, Korchemsky GP, Tseytlin AA, 2023,
Exact strong coupling results in N=2 Sp(2N) superconformal gauge theory from localization
, The Journal of High Energy Physics, Vol: 2023, ISSN: 1029-8479We apply the localization technique to compute the free energy on four-sphere and the circular BPS Wilson loop in the four-dimensional N = ∈ superconformal Sp(2N) gauge theory containing vector multiplet coupled to four hypermultiplets in fundamental representation and one hypermultiplet in rank-2 antisymmetric representation. This theory is unique among similar N = ∈ superconformal models that are planar-equivalent to N = ∆ SYM in that the corresponding localization matrix model has the interaction potential containing single-trace terms only. We exploit this property to show that, to any order in large N expansion and an arbitrary ’t Hooft coupling λ, the free energy and the Wilson loop satisfy Toda lattice equations. Solving these equations at strong coupling, we find remarkably simple expressions for these observables which include all corrections in 1/N and 1/√λ. We also compute the leading exponentially suppressed O(e-√λ) corrections and consider a generalization to the case when the fundamental hypermultiplets have a non-zero mass. The string theory dual of this N = ∈ gauge theory should be a particular orientifold of AdS5 × S5 type IIB string and we discuss the string theory interpretation of the obtained strong-coupling results.
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