Th e B i r t h o f P a r t i c l e Cos m ol og y

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Pr of e s s or D a v i d K a i s e r , 2 D e c e m be r 2 0 2 0

Particle Cosmology T oday

Stu d ie s s m a lle s t u n its o f ma t t e r a nd t he i r r ol e i n de t e r mi ni ng t he s ha pe a nd f a t e of t he e nt i r e uni ve r s e .

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• 2 n e w p r e p r i n t s ever y hour of e ve r y da y

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Not ba d f or a f ie ld tha t didn’ t e ve n exi s t 45 ye a r s a go!

Ho w d o n ew f i el d s emer g e?

Co mmo n o r i g i n s s t o r y : n e w i d e a s i n mi d - 1970s m a de i t “n at u ral ” fo r p art i cl e t h eo ri s t s t o s t u d y t h e earl y u n i v ers e, an d — pr e st o c ha ngo — th e n e w su b f ie ld w a s b o r n .

The w ho le s to r y ?

In stitu tion s an d tra in in g pr ove d c r i t i c a l . F ol l ow t w o se ts of ide a s — one f r om gr a vi t a t i on a nd t he ot he r f r om pa r t i c l e t he or y — fro m t h e 1 9 6 0 s t h ro u g h t h e 1 9 8 0 s . J u s t lik e r a d io a c tiv e d y e s, th e y se r v e a s tr a c e r s, illu min a tin g la r g e r p r o c e sse s.

1. T he P r obl e m of M a s s : A T a l e of T w o  ’s

2. I ns t i t ut i ons a nd I de a s

3. T r a i ni ng a nd N e w Habi t s

The Problem of Mass

Imp o rt a n t q u e s t i o n d u ri n g t h e e a rl y 1 9 6 0 s :

wh y d o o b j e c t s h a v e m a s s ?

Grav itation an d C osm ology . M a c h ’ s p r i n c i p l e : A r e loc a l ine r tia l e f f e c ts the r e sult of dista nt gr a vita tiona l inte r a c tions?

Partic le Ph y sic s . M a s s e s o f f o r c e - car r y i n g p ar t i cl es : How c a n the nuc le a r f or c e ha ve a f inite r a nge without viola ting ga uge sym m e tr ie s?

Scalar Solutions, 1

Ar ound the sa m e tim e , physic ists in both f ie lds pr opose d a nswe r s to e xpla in the or igin of m a ss.

Ei n s t e i n :

Br a n s - Di c k e :

[(1/ G ) R ]

[  R -  (  ,i  ,i ) /  ]

Br a ns - Di c k e , 1 9 6 1 : I n tr o d u c e n e w sc a la r f ie ld,  , so t ha t N e w t on ’ s gr a vi t a t i ona l c onst a nt va r i e s ove r spa c e a nd tim e : G ~ 1/  ( x ) .

Ro b e r t Di c k e

Ca r l Br a n s

Al l m at t er i n t er act s wi t h  , w h i c h l e a d s t o t h e obs e r ve d i ne r t i a l be ha vi o r .

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Jef f r ey G o l d st o n e

Pe t e r H i g g s

Goldston e , H iggs, e t al. , 1961 - 64 : In t ro d u c e n e w s c a l a r fi e l d ,  , whose pote ntia l, V (  ) , l e a d s t o spontane ous sy mme try b r e ak ing .

Scalar Solutions, 2

Al l m at t er i n t er act s wi t h  , w h i c h l e a d s t o t h e

obs e r ve d pa r t i c l e ma s s e s .

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Communities and their Objects

Th e tw o c o m m u n itie s s a w d if f e r e n t th in g s in th e ir re s p e c t i v e  ’s :

No o n e su g g e st e d t h a t  BD an d  H mi g h t b e si m i l a r , o r e v e n wo r t h c o n si d e r i n g si d e b y si d e , be f or e t he l a t e 1970s .

Both Papers Became “Renowned”…

… Y et Almost No Overlap

On l y 6 p a p e r s o u t o f 1 0 8 3 c i t e d bot h Br a ns - Di c k e and

Hig g s be t w e e n 1961 - 81; e a r l i e st i n 1972, m ost a f t e r 1975.

On l y 2 1 a u t h o r s o u t o f 9 9 0 c i t e d bot h Br a ns - Di c k e and

Hig g s – usua l l y i n se pa r a t e pa pe r s – be t w e e n 1961 - 81.

Historical Objects

Wh y n o o v e r l a p ? W e r e t h e s c a l a r f i e l d s f u n d a m e n t a l l y dif f e r e nt f r om e a c h othe r ?

No: in 1979, An t h o n y Z e e an d Le e S m olin each sugge ste d tha t  BD an d  H mi g h t b e phy sic ally ide ntic al .

So t h e o b j e c t s ’ c h a n g i n g s t a t u s c a n ’ t b e a f u n c t i o n only of the things in the m se lve s. The obje c ts’ sta tus an d i d en t i t y w er e historic al .

Wh a t h a d c h a n g e d ?

Questions?

Changes in Data?

Th e Ei n s t e i n a n d B r a n s - Di c k e gr a vi t a t i ona l t he or i e s w e r e s ubj e c t e d t o a s er ies o f h ig h - pr e c i s i on t e s t s dur i ng th e 1 9 6 0 s an d 1 9 7 0 s :

so l a r o b l a t e n e ss (1 9 6 6 , 1 9 7 4 )

ra d i o ra n g i n g t o t h e V i k i n g M a rs sp a c e c ra f t (1 9 7 9 ).

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Lim ite d  ≥ 500 . E i n s t e i n ’ s v e r s i o n s e e m e d f a v o r e d – just a t the tim e tha t m a ny pa r tic le the or ists be c a m e inte r e ste d in  BD .

Me a n w h i l e , a f t e r s e v e r a l d e c a d e s o f i n t e n s e se a r c hing, the f ir st e xpe r im e nta l e vide nc e f or  H only cam e t o g et h er i n 2012!

Changes in Particle Theory

As y m p t o t i c f r e e d o m (1 9 7 3 ), G U T s (1 9 7 4 ).

It b ecam e “n at u ral ” fo r pa r t i c l e t he or i st s t o be gi n as k i n g ab o u t t h e h i g h - en er g y earl y u n i v ers e.

Co s mo l o g y w o u l d p r o v i d e th e “ p o o r ma n ’ s accel erat o r . ”

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The Whole Story?

Although c e r ta inly im por ta nt, the se ide a s a r e insuf f ic ie nt to e xpla in the c r e a tion of the ne w f ie ld. The tim ing is a bit of f .

Pu b l i c a t i o n s o n c o s m o l o g y be ga n a s t e e p r i s e be f or e 1973 - 74, a nd t he r a t e of i nc r e a s e w a s una f f e c t e d by t he pa r t i c l e th eo r y p ap er s .

Th o u g h i n t r o d u c e d i n 1 9 7 4 , GU T s d i d n o t g e t m u c h a t t e n t i o n (e v e n fro m p a rt i c l e t h e o ri s t s ) unt i l t he e a r l y 1980s .

Institutions and Infrastructure

Dé t e n t e , a n t i - Vi e t n a m Wa r p r o t e s t s , M a n s f i e l d Am e n d m e n t : t h e fi rs t C o l d Wa r b u b b l e b u r s t c a . 1 9 6 8 -

72. P hys i c i s t s i n U S s a w

th eir d is cip lin e in cr is is .

Ha r d e s t h i t : p ar ticle p h y s icis ts . US b u d g e t fo r h i g h - en er g y p h y s ics cu t b y 5 0 % b etw een 1 9 7 0 - 74, co m b in ed w ith s u d d en d r o p in gove r nm e nt de m a nd f or hi gh - en er g y p h y s icis ts .

Greener Pastures

Ra p i d o u t - fl o w o f U S pa r t i c l e physi c i st s t o ot he r fi el d s , w i t h i n an d b ey o n d physi c s. B e t w e e n 1968 - 1970, tw ic e as m an y p eo p l e le ft pa r t i c l e physi c s a s e nt e r e d i t .

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1972 N AS r e por t : P a r tic le th e o r ists f a r e d so p o o r ly wh e n t h e c r u n c h c a m e b e c a u s e t h e i r t r a i n i n g wa s t o o spe c ia liz e d. N e e d to r e va m p how pa r tic le the or ists a r e tr a in e d . ( O n ly su b f ie ld sin g le d o u t f o r su c h c r itic ism in th e 2500 - pa ge r e por t .)

Pedagogical Hybrids

In t h e wa k e o f t h e c ru n c h , a ft e r t h e i n i t i a l wa v e o f o u t wa rd mi g r a t i o n f r o m p a r t i c l e t h e o r y , c a me mo r e f o r ma l i z e d c u r r i c u l a r ch an g es in th e s u b f ield , in clu d in g m o r e f o cu s o n g r av itatio n .

Ne w g ra d u a t e c o u rs e s ; gr a vi t a t i on a nd c os m ol ogy be ga n t o a ppe a r m or e of t e n on gr a dua t e s t ude nt s ’ ge ne r a l e xa m i na t i ons .

Fl o o d o f n e w GR tex tb o o k s : 4 6 p u b lis h ed dur i ng 1970s ( twice ra t e fo r 1 9 6 0 s ) – tw o - th ir d s be t w e e n 1975 - 79 a l one .

Questions?

Br o k en - S ymmet r i c G r a vi t y

I n 1979, An t h on y Z e e an d Le e S m o l i n inde pe nde ntly intr oduc e d a ne w m ode l, uniting  BD an d  H .

No w t h e l o c a l s t r e n g t h o f g r a v i t y v a r i e s a s G ~ 1/  2 . I t s pr e se nt - da y va l ue onl y e m e r ge s a f t e r  se ttle s into the min imu m o f its s y mme tr y - br e a ki ng pot e nt i a l , V .

Wh y i s g rav i t y s o w eak (co m p ared t o o t h er fo rces )?

Be c a u s e o n c e  = ± v , i t pushe s G ~ 1 / v 2 << 1 .

The Generations of 

Antho ny Z e e wa n d e re d i n t o c o s m o l o g y fro m pa r t i c l e t he or y . H e f i ni s he d hi s P h. D . i n 1970; Pa ri s s a b b a t i c a l i n 1 9 7 4 s p a rk e d h i s i n t e re s t i n co s m o lo g y . H is f ir s t p ap er s id en tif y in g  BD an d

 H ap p ear ed in 1 9 7 9 .

Lee S mo lin en ter ed g r ad u ate s ch o o l in 1 9 7 5 ; fo rm a l l y s t u d i e d p a rt i c l e t h e o ry and GR / c o s m o l o g y fro m t h e s t a rt . St u d i e d wi t h De s e r , We i n b e r g , Co l e m a n , Ge o r g i , ’t H o o ft . Id e n t i fi e d  BD an d  H in h is 1 9 7 9 d is s er tatio n .

Sm o l i n ’ s e x p e ri e n c e s b e c a m e ro u t i n e : Mi c h a e l T u r n e r , Ro c ky K o l b , a n d Pa u l S t e i n h a r d t (a l l 1 9 7 8 Ph .D.s ) t ra i n e d i n si m i l a r w a y s; a l l so o n l e d g r o u p s i d e n t i f y i n g  BD an d  H .

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Objects vs. Theories

Th o u g h f e w t h i n k t h a t t h e B r a n s - Di c k e th eo r y de s c r i be s gr a vi t y to d a y , th e obj e c t  BD wa s h a rd l y k i l l e d o f f b y t h e 1 9 7 0 s ex p er im en ts .

Th e n e w g e n e r a t i o n o f t h e o r i s t s , t r a i n e d t o w o r k i n p a r t i c l e co s m o lo g y , f o u n d n ew u s es f o r  BD , fa r b e y o n d t h e o ri g i n a l mo t i v a t i o n s o f B r a n s a n d D i c k e :

• Ge n e r i c c o r r e c t i o n t e r m s f r o m re n o rm a liz a tio n ;

• P h e n o m e n o l o g y o f s u p e r s t r i n g th e o rie s ;

• E a r l y - uni ve r s e a l t e r a t i ons t o gr a vi t y , e . g. dur i ng i nf l a t i on.

Citatio n s actu ally in cr ea s ed dur i ng th e 1 9 8 0 s an d 1 9 9 0 s , af t e r th e ex p er im en ts th at f av o r ed  > 5 0 0 .

Object Lessons

Ne ithe r data nor th e orie s fo rc e d Sm o l i n , Tu r n e r , Ko l b , a n d St e i nha r dt to unite  BD an d  H . R a t h e r , co n cr et e ch an g es i n train in g le d to a ge ne r a tiona l shif t in wha t se e m e d “ na tur a l” to do with the se the or e tic a l obje c ts.

In t u rn , t h e s e n e w re c ru i t s b e c a m e i n s t i t u t i o n - builde r s the m se lve s, solidif ying the gr owth of pa r tic le co s m o l o g y .

Tu r n e r & K o l b : d ir ecto r s o f f ir s t “Cen ter fo r Pa rt i c l e As t ro p h y s i c s ” a t Fe rm i l a b (1 9 8 3 ); later w r o te f ir s t tex tb o o k , Th e E a r l y U n i v e r s e (1 9 9 0 ).

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Th e Po wer o f Ped a g o g y

So o n a ft e r t h e s e c h a n g e s , in f la tio n a r y co s m o lo g y wa s in tr o d u ced , w ith its o w n s p ecial s calar f ield ,  . No wa d a y s i t i s ro u t i n e t o s t u d y s c a l a r fi e l d s l i k e  BD ,  H , a n d t h e i r i l k a s p a rt o f a co m m o n p r o ject.

Th i s s e e m i n g n a t u r a l n e s s — th e b an ality o f co m b in in g th es e fi e l d s t o d a y , o r t h e b i z a re n e s s o f h o l d i n g t h e m a t a rm ’ s l e n g t h — illu s tr ates th e p o w er o f p ed ag o g y .

Va s t i n s t i t u t i o n a l c h a n g e s a n d cu r r icu lar r ef o r m s r e - sh a p e d wh a t y o u n g p h y s i c i s t s wo u l d fi n d n a t u ra l , c o m p e l l i n g , o r wo rt h p u rs u i n g .

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