New CMB constraints for Abelian Higgs cosmic strings

Lizarraga, Joanes; Urrestilla, Jon; Daverio, David; Hindmarsh, Mark; Kunz, M.

doi:10.1088/1475-7516/2016/10/042

Cited by 90 publications

(114 citation statements)

References 39 publications

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“…Stronger constraints can be derived from bounds on high-energy particle emission [52], or Cosmic Microwave Background fluctuations [3] if the fields making the string are decoupled from the Standard Model.…”

Section: E Conclusionmentioning

confidence: 99%

“…Field theory simulations have successfully been used for many years to calculate the power spectrum of Cosmic Microwave Background (CMB) fluctuations from cosmic strings [1][2][3]. Searching for the imprint of strings is a powerful way to search for phase transitions just below the energy scale of inflation, which could be as high as the Grand Unification scale.…”

Section: Introductionmentioning

confidence: 99%

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Scaling from gauge and scalar radiation in Abelian-Higgs string networks

et al. 2017

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We investigate cosmic string networks in the Abelian Higgs model using data from a campaign of large-scale numerical simulations on lattices of up to 4096 3 grid points. We observe scaling or selfsimilarity of the networks over a wide range of scales, and estimate the asymptotic values of the mean string separation in horizon length unitsξ and of the mean square string velocityv 2 in the continuum and large time limits. The scaling occurs because the strings lose energy into classical radiation of the scalar and gauge fields of the Abelian Higgs model. We quantify the energy loss with a dimensionless radiative efficiency parameter, and show that it does not vary significantly with lattice spacing or string separation. This implies that the radiative energy loss underlying the scaling behaviour is not a lattice artefact, and justifies the extrapolation of measured network properties to large times for computations of cosmological perturbations. We also show that the core growth method, which increases the defect core width with time to extend the dynamic range of simulations, does not introduce significant systematic error. We compareξ andv 2 to values measured in simulations using the Nambu-Goto approximation, finding that the latter underestimate the mean string separation by about 25%, and overestimatev 2 by about 10%. The scaling of the string separation implies that string loops decay by the emission of massive radiation within a Hubble time in field theory simulations, in contrast to the Nambu-Goto scenario which neglects this energy loss mechanism. String loops surviving for only one Hubble time emit much less gravitational radiation than in the Nambu-Goto scenario, and are consequently subject to much weaker gravitational wave constraints on their tension.

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Section: E Conclusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Scaling from gauge and scalar radiation in Abelian-Higgs string networks

et al. 2017

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“…The existence of cosmic strings can be tested using the cosmic microwave background (CMB) measurements. Confronting experimental CMB data with numerical simulations of cosmic string networks [20][21][22][23], the string tension is constrained to be smaller than a few 10 −7 .…”

Section: Introductionmentioning

confidence: 99%

Constraints on cosmic strings using data from the first Advanced LIGO observing run

Abbott¹,

Abbott²,

Abbott³

et al. 2018

Phys. Rev. D

146

173

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Cosmic strings are topological defects which can be formed in grand unified theory scale phase transitions in the early universe. They are also predicted to form in the context of string theory. The main mechanism for a network of Nambu-Goto cosmic strings to lose energy is through the production of loops and the subsequent emission of gravitational waves, thus offering an experimental signature for the existence of cosmic strings. Here we report on the analysis conducted to specifically search for gravitational-wave bursts from cosmic string loops in the data of Advanced LIGO 2015-2016 observing run (O1). No evidence of such signals was found in the data, and as a result we set upper limits on the cosmic string parameters for three recent loop distribution models. In this paper, we initially derive constraints on the string tension Gμ and the intercommutation probability, using not only the burst analysis performed on the O1 data set but also results from the previously published LIGO stochastic O1 analysis, pulsar timing arrays, cosmic microwave background and big-bang nucleosynthesis experiments. We show that these data sets are complementary in that they probe gravitational waves produced by cosmic string loops during very different epochs. Finally, we show that the data sets exclude large parts of the parameter space of the three loop distribution models we consider.

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“…For an actual Nambu-Goto string simulation, Lazanu & Shellard (2015) has computed a limit of Gµ < 1.5 × 10 −7 . And for Abelian-Higgs strings Lizarraga et al (2016) have found the limit to be 2.0 × 10 −7 .…”

Section: Cosmological Detection Of Cosmic Stringsmentioning

confidence: 99%

Information theoretic bounds on cosmic string detection in CMB maps with noise

Ciuca

Hernández

2019

Monthly Notices of the Royal Astronomical Society

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We use a convolutional neural network (CNN) to study cosmic string detection in cosmic microwave background (CMB) flat sky maps with Nambu-Goto strings. On noiseless maps we can measure string tensions down to order 10 −9 , however when noise is included we are unable to measure string tensions below 10 −7 . Motivated by this impasse, we derive an information theoretic bound on the detection of the cosmic string tension Gµ from CMB maps. In particular we bound the information entropy of the posterior distribution of Gµ in terms of the resolution, noise level and total survey area of the CMB map. We evaluate these bounds for the ACT, SPT-3G, Simons Observatory, Cosmic Origins Explorer, and CMB-S4 experiments. These bounds cannot be saturated by any method.

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New CMB constraints for Abelian Higgs cosmic strings

Cited by 90 publications

References 39 publications

Scaling from gauge and scalar radiation in Abelian-Higgs string networks

Scaling from gauge and scalar radiation in Abelian-Higgs string networks

Constraints on cosmic strings using data from the first Advanced LIGO observing run

Information theoretic bounds on cosmic string detection in CMB maps with noise

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