Pub Date : 2024-12-20DOI: 10.1088/1475-7516/2024/12/054
Wayne Hu, Qiuyue Liang, Meng-Xiang Lin and Mark Trodden
We consider the effects of relaxing the assumption that gravitational waves composing the stochastic gravitational wave background (SGWB) are uncorrelated between frequencies in analyses of the data from Pulsar Timing Arrays (PTAs). While uncorrelated monochromatic plane waves are often a good approximation, a background composed of unresolved astrophysical sources cannot be exactly uncorrelated since an infinite plane wave propagates no temporal signal. We consider how relaxing this assumption allows us to extract potential information about modified dispersion relations and other fundamental physics questions, as both the group and phase velocity of waves become relevant. After developing the formalism we carry out simple Gaussian wavepacket examples and then consider more realistic waveforms, such as that from binary inspirals. When the frequency evolves only slowly across the PTA temporal baseline, the monochromatic assumption at an effective mean frequency remains a good approximation and we provide scaling relations that characterize its accuracy.
{"title":"Testing gravity with realistic gravitational waveforms in Pulsar Timing Arrays","authors":"Wayne Hu, Qiuyue Liang, Meng-Xiang Lin and Mark Trodden","doi":"10.1088/1475-7516/2024/12/054","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/054","url":null,"abstract":"We consider the effects of relaxing the assumption that gravitational waves composing the stochastic gravitational wave background (SGWB) are uncorrelated between frequencies in analyses of the data from Pulsar Timing Arrays (PTAs). While uncorrelated monochromatic plane waves are often a good approximation, a background composed of unresolved astrophysical sources cannot be exactly uncorrelated since an infinite plane wave propagates no temporal signal. We consider how relaxing this assumption allows us to extract potential information about modified dispersion relations and other fundamental physics questions, as both the group and phase velocity of waves become relevant. After developing the formalism we carry out simple Gaussian wavepacket examples and then consider more realistic waveforms, such as that from binary inspirals. When the frequency evolves only slowly across the PTA temporal baseline, the monochromatic assumption at an effective mean frequency remains a good approximation and we provide scaling relations that characterize its accuracy.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"30 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1088/1475-7516/2024/12/056
Christopher Cain
The reduced speed of light approximation (RSLA) has been employed to speed up radiative transfer simulations of reionization by a factor of ≳ 5-10. However, it has been shown to cause significant errors in the HI-ionizing background near reionization's end in simulations of representative cosmological volumes. We show that using the RSLA is, to a good approximation, equivalent to re-scaling the global ionizing emissivity in a redshift-dependent way. We derive this re-scaling and show that it can be used to “correct” the emissivity in RSLA simulations. This method requires the emissivity to be re-scaled after the simulation has been run, which limits its applicability to situations where the emissivity is set “by hand” or determined by free parameters. We test our method by running full speed of light simulations using these re-scaled emissivities and comparing them with their RSLA counterparts. We find that for reduced speeds of light c̃ ≥ 0.2, the 21 cm power spectrum at 0.1 ≤ k /[hMpc-1] ≤ 0.2 and key Lyα forest observables agree to within 20%, and often within 10%, throughout reionization. Position-dependent time-delay effects cause inaccuracies in reionization's morphology on large scales at the factor of 2 level for c̃ ≤ 0.1. Our method allows for up to a factor of 5 speedup in studies that express the emissivity in terms of free parameters, including efforts to constrain the emissivity using observations. This is a crucial step towards constraining the ionizing properties of high-redshift galaxies using efficient radiative transfer simulations.
{"title":"Towards an accurate treatment of the reduced speed of light approximation in parameterized radiative transfer simulations of reionization","authors":"Christopher Cain","doi":"10.1088/1475-7516/2024/12/056","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/056","url":null,"abstract":"The reduced speed of light approximation (RSLA) has been employed to speed up radiative transfer simulations of reionization by a factor of ≳ 5-10. However, it has been shown to cause significant errors in the HI-ionizing background near reionization's end in simulations of representative cosmological volumes. We show that using the RSLA is, to a good approximation, equivalent to re-scaling the global ionizing emissivity in a redshift-dependent way. We derive this re-scaling and show that it can be used to “correct” the emissivity in RSLA simulations. This method requires the emissivity to be re-scaled after the simulation has been run, which limits its applicability to situations where the emissivity is set “by hand” or determined by free parameters. We test our method by running full speed of light simulations using these re-scaled emissivities and comparing them with their RSLA counterparts. We find that for reduced speeds of light c̃ ≥ 0.2, the 21 cm power spectrum at 0.1 ≤ k /[hMpc-1] ≤ 0.2 and key Lyα forest observables agree to within 20%, and often within 10%, throughout reionization. Position-dependent time-delay effects cause inaccuracies in reionization's morphology on large scales at the factor of 2 level for c̃ ≤ 0.1. Our method allows for up to a factor of 5 speedup in studies that express the emissivity in terms of free parameters, including efforts to constrain the emissivity using observations. This is a crucial step towards constraining the ionizing properties of high-redshift galaxies using efficient radiative transfer simulations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"11 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1088/1475-7516/2024/12/055
Anna Chiara Alfano, Orlando Luongo and Marco Muccino
Recent outcomes by the DESI Collaboration have shed light on a possible slightly evolving dark energy, challenging the standard ΛCDM paradigm. To better understand dark energy nature, high-redshift observations like gamma-ray burst data become essential for mapping the universe expansion history, provided they are calibrated with other probes. To this aim, we calibrate the Ep - Eiso (or Amati) correlation through model-independent Bézier interpolations of the updated Hubble rate and the novel DESI data sets. More precisely, we provide two Bézier calibrations: i) handling the entire DESI sample, and ii) excluding the point at zeff = 0.51, criticized by the recent literature. In both the two options, we let the comoving sound horizon at the drag epoch, rd, vary in the range rd ∈ [138, 156] Mpc. The Planck value is also explored for comparison. By means of the so-calibrated gamma-ray bursts, we thus constrain three dark energy frameworks, namely the standard ΛCDM, the ω0CDM and the ω0ω1CDM models, in both spatially flat and non-flat universes. To do so, we worked out Monte Carlo Markov chain analyses, making use of the Metropolis-Hastings algorithm. Further, we adopt model selection criteria to check the statistically preferred cosmological model finding a preference towards the concordance paradigm with a zero curvature parameter. Nonetheless, the criteria also show a weak preference towards the non-flat ΛCDM and the flat ω0CDM scenario, leaving open to the possibility of such models as alternatives to the flat concordance paradigm. Finally, we compared the constraints got from the prompt emission Ep - Eiso correlation with those from the prompt-afterglow emission LX - TX - Lp correlation.
{"title":"Cosmological constraints from calibrated Ep - E iso gamma-ray burst correlation by using DESI 2024 data release","authors":"Anna Chiara Alfano, Orlando Luongo and Marco Muccino","doi":"10.1088/1475-7516/2024/12/055","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/055","url":null,"abstract":"Recent outcomes by the DESI Collaboration have shed light on a possible slightly evolving dark energy, challenging the standard ΛCDM paradigm. To better understand dark energy nature, high-redshift observations like gamma-ray burst data become essential for mapping the universe expansion history, provided they are calibrated with other probes. To this aim, we calibrate the Ep - Eiso (or Amati) correlation through model-independent Bézier interpolations of the updated Hubble rate and the novel DESI data sets. More precisely, we provide two Bézier calibrations: i) handling the entire DESI sample, and ii) excluding the point at zeff = 0.51, criticized by the recent literature. In both the two options, we let the comoving sound horizon at the drag epoch, rd, vary in the range rd ∈ [138, 156] Mpc. The Planck value is also explored for comparison. By means of the so-calibrated gamma-ray bursts, we thus constrain three dark energy frameworks, namely the standard ΛCDM, the ω0CDM and the ω0ω1CDM models, in both spatially flat and non-flat universes. To do so, we worked out Monte Carlo Markov chain analyses, making use of the Metropolis-Hastings algorithm. Further, we adopt model selection criteria to check the statistically preferred cosmological model finding a preference towards the concordance paradigm with a zero curvature parameter. Nonetheless, the criteria also show a weak preference towards the non-flat ΛCDM and the flat ω0CDM scenario, leaving open to the possibility of such models as alternatives to the flat concordance paradigm. Finally, we compared the constraints got from the prompt emission Ep - Eiso correlation with those from the prompt-afterglow emission LX - TX - Lp correlation.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"55 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1088/1475-7516/2024/12/052
Sergio Sevillano Muñoz
Screening mechanisms are a natural method for suppressing long-range forces in scalar-tensor theories as they link the local background density to their strength. Focusing on Brans-Dicke theories, those including a non-minimal coupling between a scalar degree of freedom and the Ricci scalar, we study the origin of these screening mechanisms from a field theory perspective, considering the influence of the Standard Model on the mechanisms. Additionally, we further consider the role of scale symmetries on screening, demonstrating that only certain sectors, those obtaining their mass via the Higgs mechanism, contribute to screening the fifth forces. This may have significant implications for baryons, which obtain most of their mass from the gluon's binding energy. However, a definitive statement requires extending these calculations to bound states. We show that the non-minimally coupled field's interactions with the Higgs lead to an extensive region of the parameter space where screening mechanisms create spatially dependent fermion masses. We say that the field over-screens when this effect is more significant than the fifth forces suppressed by screening mechanisms, as we illustrate for the chameleon and symmetron models.
{"title":"A particle's perspective on screening mechanisms","authors":"Sergio Sevillano Muñoz","doi":"10.1088/1475-7516/2024/12/052","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/052","url":null,"abstract":"Screening mechanisms are a natural method for suppressing long-range forces in scalar-tensor theories as they link the local background density to their strength. Focusing on Brans-Dicke theories, those including a non-minimal coupling between a scalar degree of freedom and the Ricci scalar, we study the origin of these screening mechanisms from a field theory perspective, considering the influence of the Standard Model on the mechanisms. Additionally, we further consider the role of scale symmetries on screening, demonstrating that only certain sectors, those obtaining their mass via the Higgs mechanism, contribute to screening the fifth forces. This may have significant implications for baryons, which obtain most of their mass from the gluon's binding energy. However, a definitive statement requires extending these calculations to bound states. We show that the non-minimally coupled field's interactions with the Higgs lead to an extensive region of the parameter space where screening mechanisms create spatially dependent fermion masses. We say that the field over-screens when this effect is more significant than the fifth forces suppressed by screening mechanisms, as we illustrate for the chameleon and symmetron models.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"19 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1088/1475-7516/2024/12/053
Koushik Dutta, Deep Ghosh and Biswarup Mukhopadhyaya
It is conceivable that a bosonic dark matter (DM) with non-gravitational interactions with SM particles will be accumulated at the center of a neutron star (NS) and can lead to black hole formation. In contrast to previous works with a fixed NS temperature, we dynamically determine the formation of Bose-Einstein condensate (BEC) for a given set of DM parameters, namely the DM-neutron scattering cross-section (σχn), the thermal average of DM annihilation cross-section (⟨σv⟩) and the DM mass (mχ). For both non-annihilating and annihilating DM with ⟨σv⟩ ≲ 10-26 cm3 s-1, the BEC forms for mχ ≲ 10 TeV. In case of non-annihilating DM, observations of old NS allows σχn ≲ 10-52 cm2 for 10 MeV ≤ mχ ≲ 10 GeV (with BEC) and σχn ≲ 10-47 cm2 for 5 TeV ≲ mχ ≲ 30 PeV (without BEC). This analysis shows that the electroweak mass window, 10 GeV ≲ mχ ≲ 5 TeV is essentially unconstrained by NS observations and therefore is subject only to direct detection experiments. In the annihilating DM scenario, the exclusion limits on DM parameters become weaker and even vanish for typical WIMP annihilation cross-section. However, the late-time heating of the NS enables us to probe the region with σχn ≳ 10-47 cm2, using the James Webb Space Telescope in the foreseeable future. When our results are viewed in the context of indirect searches of DM, it provides a lower limit on the ⟨σv⟩, which is sensitive to the DM thermal state.
{"title":"Improved treatment of bosonic dark matter dynamics in neutron stars: consequences and constraints","authors":"Koushik Dutta, Deep Ghosh and Biswarup Mukhopadhyaya","doi":"10.1088/1475-7516/2024/12/053","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/053","url":null,"abstract":"It is conceivable that a bosonic dark matter (DM) with non-gravitational interactions with SM particles will be accumulated at the center of a neutron star (NS) and can lead to black hole formation. In contrast to previous works with a fixed NS temperature, we dynamically determine the formation of Bose-Einstein condensate (BEC) for a given set of DM parameters, namely the DM-neutron scattering cross-section (σχn), the thermal average of DM annihilation cross-section (⟨σv⟩) and the DM mass (mχ). For both non-annihilating and annihilating DM with ⟨σv⟩ ≲ 10-26 cm3 s-1, the BEC forms for mχ ≲ 10 TeV. In case of non-annihilating DM, observations of old NS allows σχn ≲ 10-52 cm2 for 10 MeV ≤ mχ ≲ 10 GeV (with BEC) and σχn ≲ 10-47 cm2 for 5 TeV ≲ mχ ≲ 30 PeV (without BEC). This analysis shows that the electroweak mass window, 10 GeV ≲ mχ ≲ 5 TeV is essentially unconstrained by NS observations and therefore is subject only to direct detection experiments. In the annihilating DM scenario, the exclusion limits on DM parameters become weaker and even vanish for typical WIMP annihilation cross-section. However, the late-time heating of the NS enables us to probe the region with σχn ≳ 10-47 cm2, using the James Webb Space Telescope in the foreseeable future. When our results are viewed in the context of indirect searches of DM, it provides a lower limit on the ⟨σv⟩, which is sensitive to the DM thermal state.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"100 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-19DOI: 10.1088/1475-7516/2024/12/051
Valeri P. Frolov
We study spinoptics equations in the Schwarzschild spacetime. We demonstrate that using the explicit and hidden symmetries of this metric one can explicitly solve the equations for complex null tetrad associated with null rays representing photon's and graviton's motion. This allows one to integrate the spinoptics equations both for the electromagnetic and gravitational waves. It is shown that the main effect of the interaction of the spin of these fields with the spacetime curvature is the tilt of the asymptotic planes of the massless particle orbit. The corresponding tilting angle is calculated. It is shown that this angle grows when a null ray passes in the vicinity of the circular null orbit located at r=3M.
{"title":"Spinoptics in the Schwarzschild spacetime","authors":"Valeri P. Frolov","doi":"10.1088/1475-7516/2024/12/051","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/051","url":null,"abstract":"We study spinoptics equations in the Schwarzschild spacetime. We demonstrate that using the explicit and hidden symmetries of this metric one can explicitly solve the equations for complex null tetrad associated with null rays representing photon's and graviton's motion. This allows one to integrate the spinoptics equations both for the electromagnetic and gravitational waves. It is shown that the main effect of the interaction of the spin of these fields with the spacetime curvature is the tilt of the asymptotic planes of the massless particle orbit. The corresponding tilting angle is calculated. It is shown that this angle grows when a null ray passes in the vicinity of the circular null orbit located at r=3M.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"47 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142848987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-19DOI: 10.1088/1475-7516/2024/12/049
Abraham Arvizu, Alejandro Aviles, Juan Carlos Hidalgo, Eladio Moreno, Gustavo Niz, Mario A. Rodriguez-Meza, Sofía Samario and The LSST Dark Energy Science collaboration
One of the main obstacles for the signal extraction of the three point correlation function using photometric surveys, such as the Rubin Observatory Legacy Survey of Space and Time (LSST), will be the prohibitive computation time required for dealing with a vast quantity of sources. Brute force algorithms, which naively scales as 𝒪(N3) with the number of objects, can be further improved with tree methods but not enough to deal with large scale correlations of Rubin's data. However, a harmonic basis decomposition of these higher order statistics reduces the time dramatically, to scale as a two-point correlation function with the number of objects, so that the signal can be extracted in a reasonable amount of time. In this work, we aim to develop the framework to use these expansions within the Limber approximation for scalar (or spin-0) fields, such as galaxy counts, weak lensing convergence or aperture masses. We develop an estimator to extract the signal from catalogs and different phenomenological and theoretical models for its description. The latter includes halo model and standard perturbation theory, to which we add a simple effective field theory prescription based on the short range of non-locality of cosmic fields, significantly improving the agreement with simulated data. In parallel to the modeling of the signal, we develop a code that can efficiently calculate three points correlations of more than 200 million data points (a full sky simulation with Nside=4096) in ∼40 minutes, or even less than 10 minutes using an approximation in the searching algorithm, on a single high-performance computing node, enabling a feasible analysis for the upcoming LSST data.
{"title":"Modeling the 3-point correlation function of projected scalar fields on the sphere","authors":"Abraham Arvizu, Alejandro Aviles, Juan Carlos Hidalgo, Eladio Moreno, Gustavo Niz, Mario A. Rodriguez-Meza, Sofía Samario and The LSST Dark Energy Science collaboration","doi":"10.1088/1475-7516/2024/12/049","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/049","url":null,"abstract":"One of the main obstacles for the signal extraction of the three point correlation function using photometric surveys, such as the Rubin Observatory Legacy Survey of Space and Time (LSST), will be the prohibitive computation time required for dealing with a vast quantity of sources. Brute force algorithms, which naively scales as 𝒪(N3) with the number of objects, can be further improved with tree methods but not enough to deal with large scale correlations of Rubin's data. However, a harmonic basis decomposition of these higher order statistics reduces the time dramatically, to scale as a two-point correlation function with the number of objects, so that the signal can be extracted in a reasonable amount of time. In this work, we aim to develop the framework to use these expansions within the Limber approximation for scalar (or spin-0) fields, such as galaxy counts, weak lensing convergence or aperture masses. We develop an estimator to extract the signal from catalogs and different phenomenological and theoretical models for its description. The latter includes halo model and standard perturbation theory, to which we add a simple effective field theory prescription based on the short range of non-locality of cosmic fields, significantly improving the agreement with simulated data. In parallel to the modeling of the signal, we develop a code that can efficiently calculate three points correlations of more than 200 million data points (a full sky simulation with Nside=4096) in ∼40 minutes, or even less than 10 minutes using an approximation in the searching algorithm, on a single high-performance computing node, enabling a feasible analysis for the upcoming LSST data.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"27 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142848983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-19DOI: 10.1088/1475-7516/2024/12/050
Yurino Mizuguchi, Tomoaki Murata and Yuichiro Tada
We develop a C++ package of the STOchastic LAttice Simulation (STOLAS) of cosmic inflation. It performs the numerical lattice simulation in the application of the stochastic-δ N formalism. STOLAS can directly compute the three-dimensional map of the observable curvature perturbation without estimating its statistical properties. In its application to two toy models of inflation, chaotic inflation and Starobinsky's linear-potential inflation, we confirm that STOLAS is well-consistent with the standard perturbation theory. Furthermore, by introducing the importance sampling technique, we have success in numerically sampling the current abundance of primordial black holes (PBHs) in a non-perturbative way. The package is available athttps://github.com/STOchasticLAtticeSimulation/STOLAS_dist.
{"title":"STOLAS: STOchastic LAttice Simulation of cosmic inflation","authors":"Yurino Mizuguchi, Tomoaki Murata and Yuichiro Tada","doi":"10.1088/1475-7516/2024/12/050","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/050","url":null,"abstract":"We develop a C++ package of the STOchastic LAttice Simulation (STOLAS) of cosmic inflation. It performs the numerical lattice simulation in the application of the stochastic-δ N formalism. STOLAS can directly compute the three-dimensional map of the observable curvature perturbation without estimating its statistical properties. In its application to two toy models of inflation, chaotic inflation and Starobinsky's linear-potential inflation, we confirm that STOLAS is well-consistent with the standard perturbation theory. Furthermore, by introducing the importance sampling technique, we have success in numerically sampling the current abundance of primordial black holes (PBHs) in a non-perturbative way. The package is available athttps://github.com/STOchasticLAtticeSimulation/STOLAS_dist.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"13 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142848985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.1088/1475-7516/2024/12/043
Amit Adhikary, Debasish Borah, Satyabrata Mahapatra, Indrajit Saha, Narendra Sahu and Vicky Singh Thounaojam
Light dark matter (DM) with mass around the GeV scale faces weaker bounds from direct detection experiments. If DM couples strongly to a light mediator, it is possible to have observable direct detection rate. However, this also leads to a thermally under-abundant DM relic due to efficient annihilation into light mediators. We propose a novel scenario where a first-order phase transition (FOPT) occurring at MeV scale can restore GeV scale DM relic by changing the mediator mass sharply at the nucleation temperature. The MeV scale FOPT predicts stochastic gravitational waves with nano-Hz frequencies within reach of pulsar timing array (PTA) based experiments like NANOGrav. In addition to enhancing direct detection rate, the light mediator can also give rise to the required DM self-interactions necessary to solve the small scale structure issues of cold dark matter. The existence of light scalar mediator and its mixing with the Higgs keep the scenario verifiable at different particle physics experiments.
{"title":"New realisation of light thermal dark matter with enhanced detection prospects","authors":"Amit Adhikary, Debasish Borah, Satyabrata Mahapatra, Indrajit Saha, Narendra Sahu and Vicky Singh Thounaojam","doi":"10.1088/1475-7516/2024/12/043","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/043","url":null,"abstract":"Light dark matter (DM) with mass around the GeV scale faces weaker bounds from direct detection experiments. If DM couples strongly to a light mediator, it is possible to have observable direct detection rate. However, this also leads to a thermally under-abundant DM relic due to efficient annihilation into light mediators. We propose a novel scenario where a first-order phase transition (FOPT) occurring at MeV scale can restore GeV scale DM relic by changing the mediator mass sharply at the nucleation temperature. The MeV scale FOPT predicts stochastic gravitational waves with nano-Hz frequencies within reach of pulsar timing array (PTA) based experiments like NANOGrav. In addition to enhancing direct detection rate, the light mediator can also give rise to the required DM self-interactions necessary to solve the small scale structure issues of cold dark matter. The existence of light scalar mediator and its mixing with the Higgs keep the scenario verifiable at different particle physics experiments.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"40 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.1088/1475-7516/2024/12/045
Mohammadreza Davari, Alireza Allahyari and Shahram Khosravi
We perform an observational study of modified gravity considering a potential inflationary interpretation of pulsar timing arrays (PTA). We use a motivated model known as no slip in which the gravitational wave propagation is modified. Specifically, by using two different parametrizations for the model, we find the approximate transfer functions for tensor perturbations. In this way, we obtain the spectral energy density of gravitational waves and use NANOGrav and IPTA second data release to constrain parameters of the model. In parametrization I, ξ is degenerate with log10A and γ and in parametrization II, cM is also degenerate with both log10A and γ. For cM, we only get an upper bound on the parameter. Thus, it is difficult to constrain them with percent level accuracy with the current PTA data.
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