G.Fiorentini 1

G. Fiorentini

: a constant that is not constant?

The QSO evidence for What else do we know about ? The Oklo natural reactor and the

constancy of Ancient meteorites, old stars and Possible improvements about and other “fundamental

constants”

00

0

G.Fiorentini 2

A Brief History of

1905 Planck: "it seems to me not completely impossiblethat h has the same order of magnitude as e2/c”

1909 Einstein :"It seems to me that we can conclude from h=e2/c that the same modification of theory that contains the elementary quantum e as a consequence will also contain the quantum structure of radiation”

1911 Sommerfeld formally defines as the ratio of the electrostatic energy of repulsion between two elementary charges, e, separated by one Compton wavelength, to the rest energy of a single charge:

137

1)//( 2

2

2

c

e

mc

mce

G.Fiorentini 3

Measurement of

Garching 2002.

•Neutron de-Broglie wavelength•Quantum Hall effect•ac Josephson effect •simple QED bound systems•electron anomalous magnetic moment (gold standard)

CODATA [1997](ae)-

1=137.03599993(52)

p.p.b.

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Inconstant constants: Dirac ‘Large Number Hypothesis'

In a letter to Nature in 1937 Dirac noted the following coincidence:

”This suggests that …large numbers are to be regarded not as constants, but as simple functions of our present epoch, expressed in atomic units. In this way we avoid the need of a theory to determine numbers of the order of 1039 “.

Thus if N1 ~N2 one must have varying constants, e.g. G ~ t-1

"...the constancy of the fundamental physical constants should be checked in an experiment" - P.A.M

Dirac

timecrossing-light atomic

universe of age106

/39

221 cme

tN

e

o

electron &proton between force nalGravitatio

electron &proton between force electric103.2 39

2

2 eN mGm

eN

G.Fiorentini 5

The QSO evidence for

J.Webb et al. PRL 87(2001)=(0.72+-0.18)10-5

0

•Absorption spectra of diffuse clouds illuminated by QSO suggest that was smaller in the past:

10-5 at 1010y ago

•Assuming linear dependence:

/ 10-15 y-1

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The method

• Look at absorption spectra of diffuse clouds illuminated by QSOs•Identify two (sets of) lines, with different dependence,to tell both z and obs=(1+z) cloud •“Alkali” doublets have provided constraints on / < 10-4

•Webb et al extended the method to different atomic species, so as to obtain a larger lever arm (many multiplet method).

QSOcloudObs.

me

me

S 1/2

P 3/2

P 1/2

Alkali doublet(fine structure)

G.Fiorentini 7

The many multiplet results

VOLUME 87, NUMBER 9 PHYSICAL REVIEW LETTERS 27 AUGUST 2001

Further Evidence for Cosmological Evolution of the Fine Structure ConstantJ. K. Webb,' M. T. Murphy,' V V Flambaum,l V A. Dzuba,l J. D. Barrow,2 C. W. Churchill,' J. X.

Prochaska,4 and A. M. Wolfe''School of Physics, University of New South Wales, Sydney, NSW 2052, Australia

ZDAMTP Centre for Mathematical Sciences, Wilberforce Road, Cambridge University, Cambridge CB3 OWA, United Kingdom 'Department of

Astronomy & Astrophysics, Pennsylvania State University, University Park, Pennsylvania 16802 4Carnegie Observatories, 813 Santa Barbara

Street, Pasadena, California 91101DDppartment of Physics and Center for Astrophysics and Space Sciences, University of California, San Diego, C-0424, La

J olla, California 920923(Received 29 December 2000; published 9 August 2001)

We describe the results of a search for time variability of the fine structure constant a usingabsorption systems in the spectra of distant quasars. Three large optical data sets and two 21 cm andmm absorption systems provide four independent samples, spanning -23% to 87% of the age of theuniverse. Each sample yields a smaller a in the past and the optical sample shows a 40- deviation: = -0.72 -±0.18 X 10-5 over the redshift range 0.5 < z < 3.5. We find no systematic effects which canexplain our results. The only potentially significant systematic effects push Aa/a towards positivevalues; i.e., our results would become more significant were we to correct for them.

DOI: 10.1103/ PhysRevLett.87.091301 PACS numbers: 98.80.Es, 06.20.J r, 95.30.Dr, 95.30.Sf

Many multiplet method: sensitivity gain by observinglines of different species (e.g. FeII and Mg II).

Lines are in quite different regions: one needs careful checks for possible miscalibrations

G.Fiorentini 8

Summary of information on d/dt

t, z connected with Ho=70Km/s/Mpc (M,)=(0.3,0.7)

Source Look backtime (Gyr)

z (d/dt)/(y-1)

Lab 4 10-10 0

Oklo 1.8 0.1

Meteorites 4.5 0.5

C 10 1.5

old stars 10 1.5

QSO(doub) 11-13 2-4

QSO(multi) + 8-12 1-3 +

CMB 14 103

BBN 14 109

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Remarks

• Only positive claim from QSO• Possibly in conflict with Oklo data

• However:-non linear evolution of ?-is space dependent?-compensation between changes of and of other “fundamental constants”? • Radioactive dating of solar system (and/or globular clusters stars) can reach sensitivity comparable to QSO

G.Fiorentini 10

Atomic Clocks

Compare clocks, with frequencies which depend differently on , and look for change in relative clock rates.

Best comparison involves H-maser ( HFS of H, 1 4 )and Hg+ atomic clock (HFS of Hg+, 2 4 Frel(Z) ) :

d/dt ln(1 / 2 ) =(dln/dt) d/d ln Frel

Measurements over 140 days have given:

(d/dt)/ < 3.7 10 y-1 (Prestage et al PRL

74(1995)3511)

Future measurements should reach 10 y-1 and be capable of testing the QSO claim.

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Atomic Clocks in space

Ultimate limit for frequency measurement is observation time. Cold atoms in lab fall due to gravity

Atoms in free fall don’t fall, i.e. go to space.

Comparison between atomic clocksin the Space Station could reach a sensitivity to

(d/dt)/10 y-1

and be capable of testing the QSO claim(ACES: www.cnes.fr/activites/connaissance/physique/aces/1sommaire_aces.htm)

G.Fiorentini 12

ACESAtomic Clocks Ensemble in Space

ACES has been approved to fly on the International Space Station as an external payload, starting from 2002 for a period of one and a half years.

It consists of the following key elements:

•A laser cooled atomic clock "PHARAO" _ contributed to the project by France,

•A Hydrogen Maser _ contributed by Switzerland,

•A laser link for optical transfer of time and frequency _ contributed by France

•A microwave link for transfer of time and

frequency _ contributed by ESA

Fundamental physics:-general relativity tests-stability of fundamental constants

Applications:

-Navigation and positioning - New concepts for higher performance GPS systems. - Geodesy with millimetric precision. - Precise tracking of remote space probes. -Time and frequency metrology - Comparing and synchronising clocks

over intercontinental distances to an

accuracy of 10-16. www.cnes.fr/activites/connaissance/physique/aces/

1sommaire_aces.htm)

G.Fiorentini 13

The Oklo phenomenon

•A natural fission reactorwhich released about 20 KW for 700 000 yearsabout 1.8 Gyr ago

Oklo gives the most strict bound :<10-7

(d/dt)/ <6 10-

17

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Footprints of natural fission

•(U235/U238)World= 0.7 % (U235/U238)OKlo= 0.4 % .Who has stolen U235?

•U235/U238 3 % 2Gyr ago, enough for a water moderated reactor.

•Abundances of Rare Earths Isotopes at Oklo are similar to those produced by fission.

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What do we learn from Oklo ?

Garching 2002.

• Characteristic isotope abundances are due to large abs of thermal neutrons (e.g.: n+149Sm-> 150Sm+)• abs large due to resonances near thermal energy*, • for 149Sm Eres= 97.3 meV today• At reactor time this resonance was efficient too:

Eres <0.1 eV• Electromagnetism contributes to nuclear energy levels:

Ecou/rnuc MeV.• Tiny changement of would spoil the resonance efficiency:

/ < 10-7•Shlyakhter Nature (1976), DysonDamour NPB (1996) Fujii et al NP(2000)

* KT = 50 meV at T=600 K

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Oklo and nuclearclocks

Garching 2002.

•One is comparing nuclear reaction rates now and at Oklo time.

•Essentially one is comparing two nuclear clocks

•These are sensitive both to e.m and nuclear forces: Ecou/rnuc

•(Warning: compensation between and rnuc ?)

•Other nuclear clocks are available in nature (reaction rates in stars, nuclear lifetimes…)

G.Fiorentini 17

Nuclear lifetimes and

Garching 2002.

• Nuclear lifetimes can depend strongly on

• e.g.: alpha decay U238 exp[-104 ]

• Merit factor for sensitivity to change of is: s= dln / dln •The highest sensitivity is for 187Re->187Os+e+ , due to the very small Q value (2,5 KeV), which depends on the Coulomb contribution to nuclear levels, which depends on Dyson 1972

Nucleus Decay 1/ 2(y) s

U238 2 109 +120

K40 EC 1.3 109 -30

Re187 4 1010 -18000

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Radioactive datings of the solar system

•The age of old meteorites can be determined by means of different radioactive methods (e.g.: U/Th almost insensible to , whereas Re/Os strongly sensitive to )•Each dating determines x= age <Dec_Rate>met.

•One determines age by one method and use the measured Os/Re value to derive a geochemical value of Re decay rate•Geochemistry <>met. =(2.400.02)10-11 y-1

•Lab.measurement pres =(2.360.04)10-11 y-1

•Comparison [pres- <>met ]/ pres= (1 1)10-6

+ linear evol. 0.40.5)10-15 y-1

/Sensitivity worse than Oklo, however comparable to QSO

G.Fiorentini 19

12C synthesis

•Our existence relies on a nuclear accident, a suitably placed 12C excited level which makes carbon synthesis efficient in stars at kT10KeV, through

-> 12C* -> 12C •We measure now: m = m12*-3m =379.5KeV

• m contains a Coulomb contribution Ecou/rnuc .•We see 12C in old stars. This implies the resonance has not moved by more than kT=10KeV--->/ < 10-2

• Conceptually, the same argument as Oklo.• Sensitivity is worse than Oklo, due to larger kT• However it probes older times, t 10 Gyr

G.Fiorentini 20

Radioactive dating of old stars

Cayrel et al.Nature 409(2001)

•Radioactive dating has been extendedto the oldest stars in the Galaxy, essentially by means of Th decay.

•Recently measurement of a stellar ageby means of U decay has been obtained

•Significant improvement, since U decays faster and initial abundance is better estimated:

TCayrel = (12.5 +- 3)Gyr

•This nuclear clock depends on .

G.Fiorentini 21

Measurement of stellar age from U decay

Cayrel et al. Nature 409(2001)

G.Fiorentini 22

Comparison of stellar clocks

•The evolution of globular cluster provides a standard chronometer of the Galaxy.

•This method is substantially insensitive to changes.

•The agreement with the nuclear clock within (errors of) 3 Gyr implies:

at t=12Gyr

G.Fiorentini 23

and the CMB

Garching 2002.

PHYSICAL REVIEW D, VOLUME 62, 123508

Looking for a varying in the cosmic microwave background

P. P. Avelino,1,2,* C. J. A. P. Martins,3,1,t G. Rocha,1,4,* and P. Vianal°s

°§1 Centro de Astrofzsica, Universidade do Porto, Run das Estrelas s/n, 4150-762 Porto, Portugal

2Departamento de Fisica da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal 3 Department of AppliedMathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 OWA, United Kingdom

4 Department of Physics, University of Oxford, Nuclear & Astrophysics Laboratory, Keble Road, Oxford OXI 3RH, United Kingdom5Departamento de Matemntica Aplicada da Faculdade de Ciencias da Universidade do Porto, Rua das Taipas 135,

4050 Porto, Portugal

(Received 29 August 2000; published 21 November 2000)

We perform a likelihood analysis of the recently released BOOMERanG and MAXIMA data, allowingfor the possibility of a time-varying fine-structure constant. We find that in general these data prefer a valueof a that was smaller in the past (which is in agreement with measurements of a from quasar observations).However, there are some interesting degeneracies in the problem which imply that strong statements about acannot be made using this method until independent accurate determinations of flbh

z and Ho are available. Wealso show that a preferred lower value of comes mainly from the data points around the first Doppler peak,whereas the main effect of the high-/ data points is to increase the preferred value for flbh

z (while alsotightening the constraints on flo and Ho). We comment on some implications of our results.

Change change BE change recomb.time change z(last scat.) change l(peak)

A lower seemed preferred by CMB. See however update...

G.Fiorentini 24

and BBN

Change

change mn-mp

change Nn

at freezeout

change 4He

VOLUME 33, NUMBER 4 PHYSICAL REVIEW D 15 FEBRUARY 1986

Time variation of fundamental constants, primordial nucleosynthesis, and the size of extra dimensions

E..W. Kolb, M.J. Perry and T.P. Walker

(Received 23 Septeber 1985)

In theories with extra dimensionsm the dependence of fundamentalconstants on the volume of the compact space allows one to useprimordial nucleosynthesis to probe the structure of compactdimensions during the first few minutes after the big bang. Requiringthe yield of primordial 4He to be within acceptable limits, we findthat in ten-dimensional superstring models the size of the extradimensions during primordial nucleosynthesis must have been within0.5% of their current value, while in Kaluza-Klein models the extradimensions must have been within 1% of theri current value.

for the possibility of a time-varying fine-structure constant. We findthat in general these data prefer a value of a that was smaller in thepast (which is in agreement with measurements of a from quasar

G.Fiorentini 25

, CMB and BBN : update

Garching 2002.

Early-universe constraints on a time-varying fine structureconstant

P. P. Avelino1,2, S. Esposito3,4, G. Mangano4, C. J . A. P. Martins' 5 A.

Melchiorri6, G. Miele4, O. Pisanti4, G. Rochal ,6, and P.T.P. VianalJ

Higher-dimensional theories have the remarkable feature ofpredicting a time (and hence redshift) dependence of thef̀undamental' four dimensional constants on cosmological

timescales. In this paper we update the bounds on a possiblevariation of the fine structure constant a at the time of BBN(z10) and CMB (z103). Using the recently-released high-resolution CMB anisotropy data and the latest estimates ofprimordial abundances of 4 He and D, we do not find evidencefor a varying a at more than one-sigma level at either epoch.

Astro-ph/0102144

2101

2105

BBN:

CMB:

G.Fiorentini 26

is not alone

The idea that several “fundamental constants” can vary on cosmological scales goes back to Dirac (1937)

Time variations of “fundamental Constants”are natural in theories with extra dimensions (see Marciano, Dvali, Zaldarriaga…)

GUT require that an evolution of em be accompanied by changes of i, or GUT is occasional.

G.Fiorentini 27

Concluding remarks

Actually unification requires changes of em to be accompanied by a much stronger change in strong interaction parameters (Calmet, Fritsch, Langacker….)

qcd/qcd em/em

Several consequences, since Mp,nqcd Mqcd

• Signal/bounds on dem/dt give info on other interactions• Analysis have to incorporate qcd as well asem

• Dedicated experiments are neededThe constancy of the fundamental physical constants should be checked in an experiment" - P.A.M Dirac (1937)