Looking Beyond ΛCDM to solve the BIG mysteries · Looking Beyond ΛCDM to solve the BIG mysteries...

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Looking Beyond ΛCDM to solve the BIG mysteries Specola Vaticana 10 May 2017 Michael S. Turner Kavli Institute for Cosmological Physics University of Chicago , Λ

Transcript of Looking Beyond ΛCDM to solve the BIG mysteries · Looking Beyond ΛCDM to solve the BIG mysteries...

Page 1: Looking Beyond ΛCDM to solve the BIG mysteries · Looking Beyond ΛCDM to solve the BIG mysteries ... ⇤CDM model is shown by the grey solid line. ... massive neutrinos can be approximated

Looking Beyond ΛCDM to solve the BIG mysteries

Specola Vaticana10 May 2017

Michael S. TurnerKavli Institute for Cosmological Physics

University of Chicago

, Λ

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The remarkable ΛCDM paradigm

Cosmic Microwave Background:the Universe at 380,000 yrs

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WOW!! And Λ is

still there!

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6 numbers describe the Universe from the big bang until today

Planck collaboration: CMB power spectra, likelihoods, and parameters

2 10 30

101

102

103

104

D[µK

2 ]

90 18

1000 2000 3000 4000

Multipole moment

Planck

ACT

SPT

1 0.2 0.1 0.07 0.05Angular scale

Figure 47. CMB-only power spectra measured by Planck (blue),ACT (orange), and SPT (green). The best-fit PlanckTT+lowPCDM model is shown by the grey solid line. ACT data at` > 1000 and SPT data at ` > 2000 are marginalized CMBbandpowers from multi-frequency spectra presented in Das et al.(2013) and George et al. (2014) as extracted in this work. Lowermultipole ACT (500 < ` < 1000) and SPT (650 < ` < 3000)CMB power extracted by Calabrese et al. (2013) from multi-frequency spectra presented in Das et al. (2013) and Story et al.(2012) are also shown. Note that the binned values in the range3000 < ` < 4000 appear higher than the unbinned best-fit linebecause of the binning (this is numerically confirmed by the re-sidual plot in Planck Collaboration XIII 2015, figure 9).

spectra are reported in Fig. 47. We also show ACT and SPTbandpowers at lower multipoles as extracted by Calabrese et al.(2013). This figure shows the state of the art of current CMBobservations, with Planck covering the low-to-high-multipolerange and ACT and SPT extending into the damping region. Weconsider the CMB to be negligible at ` > 4000 and note thatthese ACT and SPT bandpowers have an overall calibration un-certainty (2 % for ACT and 1.2 % for SPT).

The inclusion of ACT and SPT improves the full-missionPlanck spectrum extraction presented in Sect. 5.5 only margin-ally. The main contribution of ACT and SPT is to constrainsmall components (e.g., the tSZ, kSZ, and tSZCIB) that arenot well determined by Planck alone. However, those compon-ents are sub-dominant for Planck and are well described by theprior based on the 2013 Planck+highL solutions imposed in thePlanck-alone analysis. The CIB amplitude estimate improves by40 % when including ACT and SPT, but the CIB power is alsoreasonably well constrained by Planck alone. The main Planckcontaminants are the Poisson sources, which are treated as in-dependent and do not benefit from ACT and SPT. As a result,the errors on the extracted Planck spectrum are only slightly re-duced, with little additional cosmological information added byincluding ACT and SPT for the baseline CDM model (see alsoPlanck Collaboration XIII 2015, section 4).

6. Conclusions

The Planck 2015 angular power spectra of the cosmic mi-crowave background derived in this paper are displayed in

Fig. 48. These spectra in TT (top), T E (middle), and EE (bot-tom) are all quite consistent with the best-fit base-CDM modelobtained from TT data alone (red lines). The horizontal axis islogarithmic at ` < 30, where the spectra are shown for individualmultipoles, and linear at ` 30, where the data are binned. Theerror bars correspond to the diagonal elements of the covariancematrix. The lower panels display the residuals, the data beingpresented with di↵erent vertical axes, a larger one at left for thelow-` part and a zoomed-in axis at right for the high-` part.

The 2015 Planck likelihood presented in this work is basedon more temperature data than in the 2013 release, and onnew polarization data. It benefits from several improvementsin the processing of the raw data, and in the modelling ofastrophysical foregrounds and instrumental noise. Apart froma revision of the overall calibration of the maps, discussedin Planck Collaboration I (2015), the most significant improve-ments are in the likelihood procedures:

(i) a joint temperature-polarization pixel-based likelihood at` 29, with more high-frequency information used for fore-ground removal, and smaller sky masks (Sects. 2.1 and 2.2);

(ii) an improved Gaussian likelihood at ` 30 that includesa di↵erent strategy for estimating power spectra from data-subset cross-correlations, using half-mission data instead ofdetector sets (which allows us to reduce the e↵ect of cor-related noise between detectors, see Sects. 3.2.1 and 3.4.3),and better foreground templates, especially for Galactic dust(Sect. 3.3.1) that allow us to mask a smaller fraction of thesky (Sect. 3.2.2) and to retain large-angle temperature in-formation from the 217 GHz map that was neglected in the2013 release (Sect. 3.2.4).

We performed several consistency checks of the robustnessof our likelihood-making process, by introducing more or lessfreedom and nuisance parameters in the modelling of fore-grounds and instrumental noise, and by including di↵erent as-sumptions about the relative calibration uncertainties across fre-quency channels and about the beam window functions.

For temperature, the reconstructed CMB spectrum and er-ror bars are remarkably insensitive to all these di↵erent as-sumptions. Our final high-` temperature likelihood, referred toas “PlanckTT” marginalizes over 15 nuisance parameters (12modelling the foregrounds, and 3 for calibration uncertainties).Additional nuisance parameters (in particular, those associatedwith beam uncertainties) were found to have a negligible impact,and can be kept fixed in the baseline likelihood.

For polarization, the situation is di↵erent. Variation of the as-sumptions leads to scattered results, with larger deviations thanwould be expected due to changes in the data subsets used, andat a level that is significant compared to the statistical error bars.This suggests that further systematic e↵ects need to be eithermodelled or removed. In particular, our attempt to model cal-ibration errors and temperature-to-polarization leakage suggeststhat the T E and EE power spectra are a↵ected by systematics ata level of roughly 1 µK2. Removal of polarization systematics atthis level of precision requires further work, beyond the scope ofthis release. The 2015 high-` polarized likelihoods, referred toas “PlikTE” and “PlikEE”, or “PlikTT,EE,TE” for the com-bined version, ignore these corrections. They only include 12additional nuisance parameters accounting for polarized fore-grounds. Although these likelihoods are distributed in the PlanckLegacy Archive,15 we stick to the PlanckTT+lowP choice in thebaseline analysis of this paper and the companion papers such

15 http://pla.esac.esa.int/pla/

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The remarkable ΛCDM paradigm

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ΛCDM: today’s big pictureprecision, accuracy, full accounting and consistency

• From quark soup to nuclei and atoms to galaxies and large-scale structure

• Flat, accelerating Universe, inflationary beginning • Atoms, exotic dark matter & dark energy• Precision cosmological parameters

• T0 = 2.7255 ± 0.0006 K• Ω0 = 1.005 ± 0.005 (uncurved = flat)• ΩM = 0.315 ± 0.01• ΩB = 0.048 ± 0.001• ΩDE = 0.685 ± 0.01• H0 = 67* ± 0.5 km/s/Mpc• t0 = 13.80 ± 0.02 Gyr• ns = 0.965 ± 0.005• Nν = 3.0 ± 0.33

Consistent withimmense body of high-quality

data!

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Λ fits perfectly!

Michael S Turner

M. Betoule et al.: Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples.

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

m

0.0

0.2

0.4

0.6

0.8

1.0

JLAPLANCK+WPPLANCK+WP+BAOC11

Fig. 14. 68% and 95% confidence contours (including system-atic uncertainty) for them and cosmological parameters forthe o-CDM model. Labels for the various data sets correspondto the present SN Ia compilation (JLA), the Conley et al. (2011)SN Ia compilation (C11), the combination of Planck tempera-ture and WMAP polarization measurements of the CMB fluctu-ation (PLANCK+WP), and a combination of measurements ofthe BAO scale (BAO). See Sect. 7.1 for details. The black dashedline corresponds to a flat universe.

7.2. Constraints on cosmological parameters for various darkenergy models

We consider three alternatives to the base CDM model:

– the one-parameter extension allowing for non-zero spatialcurvature k, labeled o-CDM.

– the one-parameter extension allowing for dark energy in aspatially flat universe with an arbitrary constant equation ofstate parameter w, labeled w-CDM.

– the two-parameter extension allowing for dark energy in aspatially flat universe with a time varying equation of stateparameter parameterized as w(a) = w0 + wa(1 a) with a =1/(1 + z) (Linder 2003) and labeled wz-CDM.

We follow the assumptions of Planck Collaboration XVI (2013)to achieve consistency with our prior. In particular we assumemassive neutrinos can be approximated as a single massiveeigenstate with m = 0.06 eV and an e↵ective energy densitywhen relativistic:

= Ne↵78

4

11

!4/3

(26)

with the radiation energy density and Ne↵ = 3.046. We useTcmb = 2.7255 K for the CMB temperature today.

Best-fit parameters for di↵erent probe combinations aregiven in Tables 14, 15 and 16. Errors quoted in the ta-bles are 1- Cramér-Rao lower bounds from the approximateFisher Information Matrix. Confidence contours correspondingto 2 = 2.28 (68%) and 2 = 6 (95%) are shown inFigs. 14, 15 and 16. For all studies involving SNe Ia, we usedlikelihood functions similar to Eq. (15), with both statistical andsystematic uncertainties included in the computation of C. Wealso performed fits involving the SNLS+SDSS subsample andthe C11 “SALT2” sample for comparison (see Sect. 6).

In all cases the combination of our supernova sample withthe two other probes is compatible with the cosmological con-

Fig. 15. Confidence contours at 68% and 95% (including sys-tematic uncertainty) for the m and w cosmological parametersfor the flat w-CDM model. The black dashed line correspondsto the cosmological constant hypothesis.

Fig. 16. Confidence contours at 68% and 95% (including sys-tematic uncertainty) for the w and wa cosmological parametersfor the flat w-CDM model.

stant solution in a flat universe, which could have been antic-ipated from the agreement between CMB and SN Ia measure-ments of CDM parameters (see Sect. 6.6). This concordance isthe main result of the present paper. We note that this conclusionstill holds if we use the WMAP CMB temperature measurementin place of the Planck measurement (see Table 15).

For the w-CDM model, in combination with Planck, wemeasure w =1.018 ± 0.057. This represents a substan-tial improvement in uncertainty (30%) over the combinationPLANCK+WP+C11 (w = 1.093±0.078 ). The 1 (stat+sys)change in w is caused primarily by the recalibration of the SNLSsample as discussed in detail in Sect. 6. The improvement in er-rors is due to the inclusion of the full SDSS-II spectroscopicsample and to the reduction in systematic errors due to the jointre-calibration of the SDSS-II and SNLS surveys. As an illustra-tion of the relative influence of those two changes, using the C11calibration uncertainties would increase the uncertainty of w to6.5%.

Interestingly, the CMB+SNLS+SDSS combination deliversa competitive measurement of w with an accuracy of 6.9%, de-

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Inflation scorecardKey Predictions

• Flat Universe• Almost scale-invariant, Gaussian perturbations:

|(n-1)| ~ 0.1 and |dn/dlnk| ~ 0.001• Gravity waves: spectrum, but not amplitude • Cold Dark Matter Scenario

Key Results• Ω0 = 1.00 ± 0.006• (n-1) = -0.035 ± 0.005; dn/dlnk = -0.032 ± 0.02;

no evidence for nonGaussianity• r < 0.1 (95% cl)

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Airtight Evidence for Nonbaryonic Dark Matter

CMB & BBNΩBh2 = 0.0222 ± 0.0002

vs.CMB/SDSS

ΩMh2 = 0.142 ± 0.0013> 50σ discrepancy

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The Largest Things in the Universe Began from Subatomic Quantum Fluctuations!

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ΛCDM: a well established standard model that is amazing

• Standard hot big bang, from quark soup to galaxies and large-scale structure (t >10-6

sec)• Inflationary beginning (t << 10-6 sec) that

explains the large-scale features of the Universe and quantum origin of galaxies

• Dark Matter is comprised of slowly moving particles

• Accelerated expansion explained by the energy of nothing (mathematically, Λ)

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ΛCDM has also revealed new physics

• The repulsive gravity of Dark Energy explains cosmic acceleration and Λ (quantum vacuum energy) is the default dark energy candidate

• A very early burst of tremendous expansion – Inflation –explains our smooth, flat Universe with seeds for galaxies grown from quantum fluctuations

• The gravity of slowly-moving Dark Matter particles (CDM) holds all cosmic structures together

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• Λ is still the most profound mystery in all of science

• No standard model – let alone fundamental model – of inflation

• So what is the name of the dark matter particle?

• New physics or just epicycles?

• We can do better! ΛCDM is a model, not a theory!

But, ΛCDM is not good enough!

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Precision cosmology moves us forward through

• Disruption– H0 portal– Cosmic Acceleration

• Discovery– B-modes of inflation– Dark matter

• And on to bigger mysteries ahead!

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Precision Cosmology!

Precision Cosmologyis Hard

Accurate Cosmologyis even Harder!

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• 3.4σ discrepancy between direct measures and CMB measurements that assume ΛCDM

• If both values are right –ΛCDM disrupted!

• And discovery … but no good explanation (yet)

The H0 portal: disruption and discovery?

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• 3.4σ discrepancy between direct measures and CMB measurements that assume ΛCDM

• If both values are right –ΛCDM disrupted! + discovery

The H0 portal: disruption and discovery?

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0 0.25 0.50 0.75 1.00 1.25 1.50z

0.2

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σ8(z

)

ΛCDM: Planck+WP

SPT-3G x DES-5yrGiannantonio15

Growth of structure measurements can disrupt Λ or GR• Λ consistent with

kinematic measurements• Dynamic probe of cosmic

acceleration complements expansion history

• Cross-correlate SPT and DES datasets to %-level precision

X

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Sullivan et al 2011

Betoule et al (1401.4064)Joint Lightcurve Analysis

w = -1.02 ± 0.06 (stat + sys)wa ≈ -0.5 ± 0.8

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6 parameter fit to ΛCDM

La dent (l ~ 20 to 40): disruption or discovery?

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Discover the epoch of inflation with B-mode polarization

BICEP B-modes (dust)

• Combine SPT with BICEP/Keck and other CMB experiments

• “De-lens” (neutrino mass is a by-product!)

• Discovery potential:• Inflationary B-modes• Neutrino mass• New particle species

30X

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Discover the epoch of inflation with B-mode polarization

• Combine SPT with BICEP/Keck and other CMB experiments

• “De-lens” (neutrino mass is a by-product!)

• Discovery potential:• Inflationary B-modes• Neutrino mas• New particle species

BICEP B-modes (dust)

Lensing “turns” E into B

30X

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The bane of astronomy: dust

Planck dust map of BICEP region

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When all the “dust” settled:BICEP2/Keck/Planck joint analysis

arXi

v: 1

502.

0061

2

B-modes detected! Dust detected at > 3σEvidence for something else (GWs)?

Dus

t

GWs

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Where we are on B-modesl ~ 30 to 100 dust, l ~ 1000 lensing

30 nanoK!

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De-lensing (arXiv:1701.04396)

30 nanoK!

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Discovery: Detection of Dark Matter

• WIMP detection?• Axion detection?• Something more

exotic: few GeVparticle, SIDM, …

• Or Disruption: asymmetric DM, PBHs, modified gravity, fuzzy DM

Xenon1T, LZ, …

DAMIC, SuperCDMS

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Some Big Questions

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The Complicated Universe• Atoms : Democritus to 1964• + photons: 1964• + neutrinos (e, μ): 1967• + exotic dark matter: 1981• + CDM: 1983/4• + massive neutrinos: 1998• + dark energy: 1998• + τ neutrino: 2000• Done? Not likely!• Why is ΩCDM/ΩB ≈ 5?

I.I. RabiWho ordered that?

How much room for more:• UR: ~0.2rCMB• NR: ~0.1rcrit• Other leftovers: ??

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Sakharov Conditionsfor Baryogenesis (1967)?Famous April’s Fools Seminar?

• Baryon number violation

• CP violation

• Departure from Thermal Equilibrium Just look around!

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What to do about the multiverse• Most important

discovery since Copernicus?

• Answer to Nick’s “Big Bang” or before the “Big Bang” questions

• Is it science? (not testable)

• Many true believers (left coast) and not enough doubters