Year: 2019
Type: article
Abstract: Analyses of inflation models are usually conducted assuming a specific range---e.g., ${N}_{k}\ensuremath{\simeq}50--60$--of the number ${N}_{k}$ of $e$-folds of inflation. However, the analysis can also be performed by taking into account constraints imposed by the physics of reheating. In this paper, we apply this analysis to a class of weakly interacting massive particle (WIMP-)inflation models in which the inflaton also plays the role of dark matter. Our analysis also updates prior WIMP-inflation work with more recent Planck 2018 data. With this new analysis, inflaton potentials $V(\ensuremath{\phi})=\ensuremath{\lambda}{\ensuremath{\phi}}^{4}$ and $\ensuremath{\lambda}{\ensuremath{\phi}}_{0}^{4}[1\ensuremath{-}\mathrm{cos}(\ensuremath{\phi}/{\ensuremath{\phi}}_{0}){]}^{2}$ are ruled out, while $V(\ensuremath{\phi})=\ensuremath{\lambda}{\ensuremath{\phi}}_{0}^{4}{1\ensuremath{-}\mathrm{exp}[\ensuremath{-}(\ensuremath{\phi}/{\ensuremath{\phi}}_{0}{)}^{2}]{}}^{2}$ is slightly disfavored, and $V(\ensuremath{\phi})=\ensuremath{\lambda}{\ensuremath{\phi}}_{0}^{4}{\mathrm{tanh}}^{4}(\ensuremath{\phi}/{\ensuremath{\phi}}_{0})$ is only viable for certain reheating conditions. We verify that the results are insensitive to the WIMP or inflaton mass, for these potentials, as long as it is in the range ${m}_{\ensuremath{\phi}}\ensuremath{\lesssim}100\text{ }\text{ }\mathrm{TeV}$. In addition, we also discuss for the first time the effect of post-reheating entropy production (from, e.g., cosmological phase transitions) in this reheating-physics analysis. When accounted for, it decreases the number of $e$-folds through $\mathrm{\ensuremath{\Delta}}{N}_{k}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}(1/3)\mathrm{ln}(1+\ensuremath{\gamma})$, where $\ensuremath{\gamma}\ensuremath{\equiv}\ensuremath{\delta}s/s$ is the fractional increase in entropy. We briefly discuss the possible impact of entropy production on inflation-model constraints in earlier work.
Authors: Lingyuan Ji, Marc Kamionkowski
Institution: Johns Hopkins University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: THE KNOWLEDGE WE HAVE INFERRED FROM HUGE NEW ASTRONOMICAL DATA SETS ABOUT OUR GALAXY AND UNIVERSE IS STUNNING. EVEN MORE EXCITING ARE PROSPECTS FOR NEW MEASUREMENTS THAT WILL SOON MAKE CURRENT OBSERVATIONS OBSOLETE. STILL THEORISTS MUST BE NEVER AT REST IN THEIR QUEST FOR NOVEL WAYS TO CAPITALIZE FULLY UPON EXISTING DATA AND BE VIGILANT IN THEIR QUEST TO SEEK NEW DIRECTIONS FOR LONG-TERM GOALS FOR SPACE ASTROPHYSICS. HERE WE PROPOSE THEORETICAL WORK TO EXTRACT IN AN ENTIRELY NEW WAY A WEALTH OF VALUABLE SCIENTIFIC INFORMATION FROM CURRENT DATA SETS; TO HELP ADVANCE A RAPIDLY EMERGING FRONTIER OF PHYSICAL COSMOLOGY; AND TO EXPLORE NEW IDEAS FOR FUTURE GENERATIONS OF EXPERIMENTS. THE PROPOSED RESEARCH WILL HAVE IMPLICATIONS FOR THE PHYSICS OF THE INTERSTELLAR MEDIUM (ISM) HIGH-REDSHIFT GALAXIES COSMOLOGY AND PERHAPS OTHER AREAS OF ASTROPHYSICS. PERHAPS THE MOST SURPRISING RESULT FROM THE PLANCK SATELLITE IS THE OBSERVATION THAT THE E-MODE POWER IN DUST POLARIZATION IS TWICE THE B-MODE POWER IN STARK CONTRAST TO PRE-PLANCK EXPECTATIONS OF EQUAL E- AND B-MODE POWERS. THE PI AND COLLABORATORS HAVE RECENTLY UNDERSTOOD HOW THIS EE/BB~2 RATIO ARISES FROM FLUCTUATIONS IN THE MAGNETIZED ISM. THIS INITIAL WORK SUGGESTS THAT THE OBSERVED EE/ BB~2 RATIO HAS LESS TO DO WITH MHD TURBULENCE THAN WITH THE LARGE-SCALE PHYSICS DRIVING ISM TURBULENCE. THE PROPOSED RESEARCH WILL DEVELOP AN ARSENAL OF POWERFUL NEW TESTS TO EXPLORE MORE FULLY THE IMPLICATIONS OF THE MEASUREMENTS AND WILL BE RELEVANT FOR AN ARRAY OF OTHER MEASUREMENTS. IT IS LIKELY TO HAVE A TRANSFORMATIVE IMPACT ON OUR UNDERSTANDING OF THE ISM AND WILL ALSO BENEFIT CMB/ FOREGROUND-SEPARATION ALGORITHMS. WE ALSO PROPOSE WORK ON THE EMERGING SMALL-SCALE FRONTIER IN COSMOLOGY. PRIMORDIAL PERTURBATIONS ARE PRODUCED BY INFLATION OVER MORE THAN 20 DECADES IN DISTANCE SCALE AND OF THESE WE HAVE PROBED ONLY THE THREE LARGEST DECADES. RECENTLY SEVERAL IDEAS FOR WAYS TO PROBE PRIMORDIAL PERTURBATIONS ON SCALES SMALLER THAN THOSE ACCESSIBLE WITH GALAXY SURVEYS HAVE BEEN SUGGESTED. WE PROPOSE A COMPREHENSIVE SURVEY AMALGAMATION AND CRITICAL COMPARISON OF THE IDEAS THAT HAVE BEEN PROPOSED AND TO BRAINSTORM FOR NEW IDEAS. IN SO DOING WE WILL CHART A ROADMAP FOR A MULTI-PRONGED BUT COHERENT LONG-TERM EXPERIMENTAL PROGRAM TO UNLOCK THE TROVE OF INFORMATION ON SMALL SCALES. THE THIRD PROPOSED RESEARCH PROJECT WILL BE ON INTENSITY MAPPING (IM) A RAPIDLY GROWING EXPERIMENTAL EFFORT TO MAP THE DISTRIBUTION OF MATTER AT INTERMEDIATE REDSHIFTS WITH CARBON-MONOXIDE CII AND LYMAN-ALPHA LINES. DESPITE THE RAPID EXPERIMENTAL ADVANCES THERE IS STILL RELATIVELY LITTLE IN THE WAY OF RELEVANT THEORETICAL WORK. THERE ARE ALSO INTRIGUING RECENTLY REALIZED PROSPECTS TO LEARN FROM IM ABOUT GALAXIES AT HIGH REDSHIFTS. HERE WE PROPOSE TO INVESTIGATE A VARIETY OF WAYS TO USE IM TO CONSTRAIN THE COSMIC STAR FORMATION HISTORY THE PROPERTIES OF HIGH-REDSHIFT GALAXIES AND THE INTERGALACTIC MEDIUM. WE WILL EXPLORE OBSERVATIONAL STRATEGIES AND FOREGROUND-SEPARATION ALGORITHMS FOR IM. WE WILL ALSO DEVELOP AND MAKE PUBLICLY AVAILABLE AN ALGORITHM FOR RAPID BUT ACCURATE SIMULATIONS OF INTENSITY MAPS. THIS WORK WILL BE IMPORTANT FOR EXPERIMENTAL DESIGN AND MISSION-CONCEPT STUDIES AND TO OPEN NEW SCIENTIFIC DIRECTIONS WITH THESE MEASUREMENTS., Theoretical Physics: LHC, Gravity, Cosmology
OpenAlex ID: W2945075227