50 YEARS OF CMB RESEARCH WHAT IS NEXT? · Mukhanov & Chibisov (1981): 1st calculation of (scalar)...

50 YEARS OF CMB RESEARCH

WHAT IS NEXT?

F. R. BOUCHET

INSTITUT D’ASTROPHYSIQUE DE PARIS, CNRS

1965

1990

1999

2002 2009

1917

20??

1948

1969 ? ? T0, y, µ, ΛCDM, ns, αs, r, NG(fnl), ΩK, H0, ?…

"50 YRS OF CMB RESEARCH: WHAT'S NEXT?" 2

FINAL SPECTRUM FROM COBE/FIRAS

400σ : les barres d’erreurs ont été multipliées par 400 pour les rendre

visibles par rapport à l’épaisseur du trait montrant un corps noir

parfait à 2,728K…

1st presented 1990 @ AAS

FRANÇOIS R. BOUCHET, CASTEL GANDOLFO, 9-12 MAY 2017


TIGHT CONTRAINTS RESULT Compton scatterings of γ by hot e depletes low E (Rayleigh-Jeans, hν/kT 105, y > 1 (in standard BB), the plasma can reach statistical equilibrium. But when z < 107, there is no photon production, therefore no thermodynamical equilibrium; leads to a Bose-Einstein spectrum characterised by a chemical potential µ Very late energy release, at z

"50yrsofCMBresearch:what'snext?" 4

Also sensitive to any energy input – exotic or astrophysics – a very extended net

oftheCMBspectrum

Extending the window on small scale scalar primordial power spectrum (+9 e-folds)

FrançoisR.Bouchet,CastelGandolfo,9-12may2017

"50 yrs of CMB research: what's next?" 5

Fig.

Del

abro

uille

Pixie 4 years 50% sky proposed to NASA explorer Pgm In 12/2016 For 2023 launch (with also r cap.)

François R. Bouchet, Castel Gandolfo, 9-12 may 2017


TERRA INCOGNITA

1992 state

1st time met Zeldovich, Doroshkevich, Koffmann, Mukhanov, Shandarin



By 1994, Scott & White Give 95% CL that Doppler Peak is present 9407073

1996: year of the selection - by NASA of WMAP (against FIRE & PSI) and - by ESA of COBRAS/SAMBA as M3 of Horizon 2000+ (to become Planck)


Planck’s exhaustive temperature anistropies map

FrançoisR.Bouchet,CastelGandolfo,9-12may2017"50yrsofCMBresearch:what'snext?" 8

TTConsistencychecks(freq,DS..)


12 different CMB takes are being differenced and expressed in CMB Sigma Units è All null tests OK

Low/High precision

a

ccur

acy

Hig

h/Lo

w

NB: DS not used but for consistency checks


(+checks with WMAP, ACT, SPT...)


(and high-passed filtered at ~7o )

30 GHz

357 GHz


KIPAC, July 29th 2016 François R. Bouchet "Planck 2016 cosmology onward" 11

ThePlanck2015CMBpolarisaConskyat5arcminuteresoluCon

Whatwealreadyknew

KIPAC, July 29th 2016 François R. Bouchet "Planck 2016 cosmology onward" 12

WMAP3 About 50 locations?

Projected mass map

"50 yrs of CMB research: what's next?"

2013

TT,EE,BB,ΦΦ–early2017status


Onl

y ke

epin

g po

ints

w. s

uffic

ient

ly s

mal

l err

or b

ars,

Fig

. E C

alab

rese

1 114 000 Modes measured with TT, 60 000 with TE (not shown) 96 000 with EE … and 10’s in BB and φφ + weak constraints with TB and EB

τ = 0.055±0.009

107

And statistically isotropic…


E0

B0

TElargescalecorrelaCon

"50yrsofCMBresearch:what'snext?"

apparently a-causal physics, calling for a period of accelerated expansion (Spergel & Zaldariaga 97) So the (apparent) horizon is actually only the Hubble length

15FrançoisR.Bouchet,CastelGandolfo,9-12may2017

AdiabaCcity


?

Adiabatic IC Isocurvature IC

E0

B0


AdiabaCcity


Kinney

✔

17

Adiabatic IC Isocurvature IC


The Planck power spectrum of Temperature anisotropies


18 François R. Bouchet, Castel Gandolfo, 9-12 may 2017

Theory confronts data


19 François R. Bouchet, Castel Gandolfo, 9-12 may 2017

Planck2015-TE&EEspectra

Ø  Redcurveisthepredic'onbasedonthebestfitTTinbaseΛCDMØ  Albeitmagnificent,2015polarisaCondataandresultsare

preliminarybecauseallsystemaCcandforegrounduncertainCeshavenotbeenexhaus'velycharacterisedatO(1μK2).


Frequency averaged spectrum reduced 2 = 1.04 Frequency averaged spectrum reduced 2 = 1.01


BaseΛCDMmodel


Note that parameters from TT & TE have similar uncertainties, but beware that they are still some low level systematics in the polarisation data


Itcouldhavebeenotherwise!

And it further constrains potential deviations from the base tilted LCDM model/physics

IsocurvaturemodesfracCon

"50yrsofCMBresearch:what'snext?" 23FrançoisR.Bouchet,CastelGandolfo,9-12may2017(conservative, improvement ~ 10 in 10 years).

Whatisthevalueofns?


Mukhanov & Chibisov (1981): 1st calculation of (scalar) quantum fluctuation of the vacuum in an inflating background. ns must be ~0.96 < 1 for inflation to end.

A hundred-fold improvement in 20 years

(ns = 0.965± 0.006 2015 Planck alone)alone


Planck2015onrunning


The thin black stripe shows the prediction for single-field monomial chaotic inflationary models with 50 < N < 60.


PowerspectrumreconstrucCon


Bayesian reconstruction with varying number of nodes reconstructions weighted by their respective evidence. No strong evidence for feature or anomaly. (actually used 3 different methods, all with similar results)

9 e-folds


(Unsuccessful)Searchforfeatures


��2 actual/pdf


Planck2015:nsvsr


Similar (indirect) r constraint than with 2013 release (r0.002 < 0.10 @ 95% CL vs 0.11)

V*=(1.9x1016GeV)4(r/0.12)


CMBversusotherGWdetectors


March 27


For the not-too-distant future, direct local detections can only constrain non-scale invariant primordial GW backgrounds è Dedicated CMB experiments might soon (or not) yield a detection

Planck353GHzrevealstheGalacCcmagneCcfield

KIPAC,July29th2016FrançoisR.Bouchet"Planck2016cosmologyonward" 30

"50 yrs of CMB research: what's next?" 31 François R. Bouchet, Castel Gandolfo, 9-12 may 2017

Nextsteps?

Ø Improveconstraintsonrunning:needalongerleverarm.èmeasureE-polarisa'ontocosmicvariancetomuchsmallerscales,withmuchmorebenignforegroundsthaninTemperature.

Ø Improvedirectconstraints/detectaprimordialstochasCcbackgroundofgravitaConalwaves(goalsig_r~few10-4)èmeasureB-modepolarisa'onatrela'velylargescales,anddealwiththeintrinsicforegroundoflensing-inducedB-modes,andthenot-sobenignDustforeground.è AlsoneedtoknowthelensedE-modesverywelloverbroadrangeofscales,andatracerofthelensinggravita'onalpoten'al(Eitherexternal–e.g.,CIB--orinternal).

Ø Ofcoursefuturedatawillalsobesearchedfor“features”

"50yrsofCMBresearch:what'snext?" 32FrançoisR.Bouchet,CastelGandolfo,9-12may2017

"50 yrs of CMB research: what's next?" 33 FrançoisR.Bouchet,CastelGandolfo,9-12may2017


Planck CORE

PowerspectrumreconstrucCon

featureless

Or not!



COREteaser(for2fiducialcases)


Notguaranteed

(not enough for Generic model)

"50 yrs of CMB research: what's next?" 36 François R. Bouchet, Castel Gandolfo, 9-12 may 2017

SpaCalcurvatureconstraint


⌦k = 0.000± 0.005 (95% CL)

NB: Ωk =0.0004 ± 0.002 with SDSS3-DR12 Alam+ arXiv:1607.03155


SpaCalcurvatureconstraint


⌦k = 0.000± 0.005 (95% CL)

Melchiorri et al. 2000 Jaffe et al. 2001

Planck 2015

Note the change of axes For Planck below

A hundred-fold improvement in 15 years FrançoisR.Bouchet,CastelGandolfo,9-12may2017

Nextstep?


Ø ThePlanck+BAOCghtconstraint|ΩK|≲5×10−3(95%C.L.)showsthatspaCalcurvatureisdynamicallynegligible,affecCngcosmicexpansionbylessthan1%atanyepoch.

Ø SCll,curvaturedetecConcouldalsoconstraininflaCon.Indeed,possibleΩKisrestrictedbytheflatnessoftheinflatonpotenCal,IC,etc.E.g.:–  Slowrolleternalinfla'onstronglypredicts|ΩK|<10−4–  Falsevacuumeternalinfla'onruledoutifΩK<−10−4(Kleban&Schillo2012;Guth&Nomura2012)

Ø BUTCosmicvariancelimitshowwellwecanmeasurethespaCalcurvatureoftheUniverse.


Leonard, Bull, Allison (2016)

(cannot be convincingly distinguished from primordial fluctuations?)


Powerasymmetry


Mais pas de non gaussianité à petite échelle (fnl, gnl…) FrançoisR.Bouchet,CastelGandolfo,9-12may2017

Nextsteps?

Ø  Thereareanumberoftantalizing“anomalies”(l~20dent,lowmulCpolesalignment,staCsCcalanisotropy,etc.).

Ø  TheseareatverylargescalesinTemperature,andnotreallystaCsCcallysignificant.(+pbofaposterioristaCsCcs,recallSH)

Ø  LargescalesinpolarisaConarequitehardtomeasure.SofarthePlanckteamshaveimprovedthetaumeasurementfromEE(wrt2015).Weareworkingtowardfurtherimprovementsatthemaplevel.Staytunedforourso-calledlegacyreleaseaxerthesummer(TBC).

Ø  Itisunclear(unlikely?)thatgroundCMBmeasurementscanachieveveryreliableresultsontheselargestscales(e.g.groundpick-up,skyandfrequency(FG)coverage).

Ø Nopost-PlancksatellitedecidedL(yet?)Ø Non-CMBexperiments(21cmIntensitymapping…)willbe

evenmorechallengingifatalldoable(forthatpurpose)…


CMBbispectrumfingerprinCng

NGofequilateraltype (k1~k2~ k3):Ø  Non-canonicalkineCcterm

–  K-inflaCon–  DBIinflaCon

Ø  Higher-derivatetermsinLagrangian

–  GhostinflaConØ  EffecCvefieldtheory

NGoforthogonaltype(k1~2k2~ 2k3) :Ø  DisCnguishesbetween

differentvariantsof–  Non-canonicalkineCc

term–  HigherderivaCve

interacCons

Ø  GalileoninflaCon

NGoflocaltype(k1k2~k3):Ø  MulC-fieldmodelsØ  CurvatonØ  EkpyroCc/cyclicmodels

(AlsoNGofFoldedtypeØ  NonBunch-DavisØ  HigherderivaCve)

43"50yrsofCMBresearch:what'snext?"

LEO (Local, Equilateral, Orthogonal) are common outputs


Planck2015-Bispectrumconstraints


flocal NL = 0.8 ± 5.0 fequil NL = - 4 ± 43 fortho NL =-26 ± 21

wrt Planck2013

103 (Maxima 2001), 102 (WMAP7), 10 (Planck15)

44

A hundred-fold improvement in 14

years FrançoisR.Bouchet,CastelGandolfo,9-12may2017

Nextsteps?

Ø Generically,NGconstraintsscalewithoneoverthesquarerootofthenumberofmodesused.–  Plankmeasured/usedallTmodes.Onlythepolarisedmodesare

le[tomeasureintheCMB,whichmeansthatwecanimprovetheconstraintsbyatmostaboutafactorof2.

–  SowecannotgettotheWeaklynon-lineareffectofGRwhicharetypicallyoffnl~O(1),andevenlesstotheMaldacenaboundforsinglefieldslowrollofO(ns-1),ieO(0.04)!

–  Ofcourseadetec'oniss'llpossibleandwouldbeextremelysignificant!

Ø Togoforwardfurtherthan2DCMBmodes,turnto3Dmodes,hopefullyinlinearorperturbaCveregime.–  Intensitymappingwillhelp,buttogetclosetoMaldacena

bound,weneedatleasttogoonfarsideofthemoon…


50 YEARS OF CMB RESEARCH WHAT IS NEXT? · Mukhanov & Chibisov (1981): 1st calculation of (scalar)...

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