Probing the Inflaton: Small-Scale Power Spectrum Constraints From Measurements of the Cosmic Microwave Background Energy Spectrum

Chluba, Jens; Erickcek, Adrienne L.; Ben-Dayan, Ido

doi:10.1088/0004-637x/758/2/76

Cited by 272 publications

(366 citation statements)

References 144 publications

Supporting

Mentioning

357

Contrasting

Order By: Relevance

“…• Spectral distortions of the CMB provide what is probably the cleanest way to probe primordial small scales away from messy, hard-to-model astrophysics effects [59].…”

Section: Observing Dark Energy In the Era Of Large Surveys Plenary Spmentioning

confidence: 99%

BeyondΛCDM: Problems, solutions, and the road ahead

Bull

Akrami

Adamek

et al. 2016

Physics of the Dark Universe

442

210

View full text Add to dashboard Cite

Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, ΛCDM. This is motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm. In this paper, we summarize the current status of ΛCDM as a physical theory, and review investigations into possible alternatives along a number of different lines, with a particular focus on highlighting the most promising directions. While the fundamental problems are proving reluctant to yield, the study of alternative cosmologies has led to considerable progress, with much more to come if hopes about forthcoming high-precision observations and new theoretical ideas are fulfilled.Keywords: cosmology -dark energy -cosmological constant problem -modified gravitydark matter -early universe Cosmology has been both blessed and cursed by the establishment of a standard model: ΛCDM. On the one hand, the model has turned out to be extremely predictive, explanatory, and observationally robust, providing us with a substantial understanding of the formation of large-scale structure, the state of the early Universe, and the cosmic abundance of different types of matter and energy. It has also survived an impressive battery of precision observational tests -anomalies are few and far between, and their significance is contentious where they do arise -and its predictions are continually being vindicated through the discovery of new effects (B-mode polarization [1] and lensing [2,3] of the cosmic microwave background (CMB), and the kinetic Sunyaev-Zel'dovich effect [4] being some recent examples). These are the hallmarks of a good and valuable physical theory.On the other hand, the model suffers from profound theoretical difficulties. The two largest contributions to the energy content at late times -cold dark matter (CDM) and the cosmological constant (Λ) -have entirely mysterious physical origins. CDM has so far evaded direct detection by laboratory experiments, and so the particle field responsible for it -presumably a manifestation of "beyond the standard model" particle physics -is unknown. Curious discrepancies also appear to exist between the predicted clustering properties of CDM on small scales and observations. The cosmological constant is even more puzzling, giving rise to quite simply the biggest problem in all of fundamental physics: the question of why Λ appears to take such an unnatural value [5,6,7]. Inflation, the theory of the very early Universe, has also been criticized for being fine-tuned and under-predictive [8], and appears to leave many problems either unsolved or fundamentally unresolvable. These problems are indicative of a crisis.From January 14th-17th 2015, we held a conference in Oslo, Norway to surve...

show abstract

“…• Spectral distortions of the CMB provide what is probably the cleanest way to probe primordial small scales away from messy, hard-to-model astrophysics effects [59].…”

Section: Observing Dark Energy In the Era Of Large Surveys Plenary Spmentioning

confidence: 99%

BeyondΛCDM: Problems, solutions, and the road ahead

Bull

Akrami

Adamek

et al. 2016

Physics of the Dark Universe

442

210

View full text Add to dashboard Cite

show abstract

“…Here, |µ| is the 2σ upper limit on the chemical potential. This would already rule out many alternative early-universe models with enhanced small-scale power (Chluba et al 2012a;Clesse et al 2014). Assuming 1% priors on A sync and α sync , one could obtain A s (k 740 Mpc −1 ) < 7.3 × 10 −9 (95% c.l.…”

Section: Addition Of External Data Using Priorsmentioning

confidence: 99%

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Abitbol

Chluba

Hill

et al. 2017

Monthly Notices of the Royal Astronomical Society

Self Cite

154

View full text Add to dashboard Cite

Measurements of cosmic microwave background spectral distortions have profound implications for our understanding of physical processes taking place over a vast window in cosmological history. Foreground contamination is unavoidable in such measurements and detailed signal-foreground separation will be necessary to extract cosmological science. In this paper, we present MCMC-based spectral distortion detection forecasts in the presence of Galactic and extragalactic foregrounds for a range of possible experimental configurations, focusing on the Primordial Inflation Explorer (PIXIE) as a fiducial concept. We consider modifications to the baseline PIXIE mission (operating 12 months in distortion mode), searching for optimal configurations using a Fisher approach. Using only spectral information, we forecast an extended PIXIE mission to detect the expected average non-relativistic and relativistic thermal Sunyaev-Zeldovich distortions at high significance (194σ and 11σ, respectively), even in the presence of foregrounds. The ΛCDM Silk damping µ-type distortion is not detected without additional modifications of the instrument or external data. Galactic synchrotron radiation is the most problematic source of contamination in this respect, an issue that could be mitigated by combining PIXIE data with future ground-based observations at low frequencies (ν 15 − 30 GHz). Assuming moderate external information on the synchrotron spectrum, we project an upper limit of |µ| < 3.6 × 10 −7 (95% c.l.), slightly more than one order of magnitude above the fiducial ΛCDM signal from the damping of small-scale primordial fluctuations, but a factor of 250 improvement over the current upper limit from COBE/FIRAS. This limit could be further reduced to |µ| < 9.4 × 10 −8 (95% c.l.) with more optimistic assumptions about extra low-frequency information and would rule out many alternative inflation models as well as provide new constraints on decaying particle scenarios.

show abstract

“…Other methods of probing the primordial spectrum include methods such as Ly α [17], the absence of primordial black holes and Ultracompact Minihalos [19][20][21], measuring spectral distortions of the CMB blackbody spectrum [22][23][24], galaxy weak lensing [25], galaxy correlation functions [26] and cluster number counts [27]. All of which have either different systematics, different k range sensitivity, based on future data or some combination of the above.…”

Section: Introductionmentioning

confidence: 99%

Constraining the primordial power spectrum from SNIa lensing dispersion

Ben-Dayan

Kalaydzhyan

2014

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

The (absence of detecting) lensing dispersion of supernovae type Ia (SNIa) can be used as a novel and extremely efficient probe of cosmology. In this preliminary example we analyze its consequences for the primordial power spectrum. The main setback is the knowledge of the power spectrum in the nonlinear regime, 1 Mpc −1 ≲ k ≲ 10 2 -10 3 Mpc −1 up to redshift of about unity. By using the lensing dispersion and conservative estimates in this regime of wave numbers, we show how the current upper bound σ μ ðz ≤ 1Þ < 0.12 on existing data gives strong indirect constraints on the primordial power spectrum. The probe extends our handle on the spectrum to a total of 12-15 inflation e-folds. These constraints are so strong that they are already ruling out a large portion of the parameter space allowed by PLANCK for running α ≡ dn s =d ln k and running of running β ≡ d 2 n s =d ln k 2 . The bounds follow a linear relation to a very good accuracy. A conservative bound disfavors any enhancement above the line βðk 0 Þ ¼ 0.036-0.42αðk 0 Þ and a realistic estimate disfavors any enhancement above the line βðk 0 Þ ¼ 0.022-0.44αðk 0 Þ.

show abstract

Probing the Inflaton: Small-Scale Power Spectrum Constraints From Measurements of the Cosmic Microwave Background Energy Spectrum

Cited by 272 publications

References 144 publications

BeyondΛCDM: Problems, solutions, and the road ahead

BeyondΛCDM: Problems, solutions, and the road ahead

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Constraining the primordial power spectrum from SNIa lensing dispersion

Contact Info

Product

Resources

About