Field Quantization Without Divergences

34
Field Quantization Without Divergences John R. Klauder University of Florida Gainesville, FL

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Field Quantization Without Divergences. John R. Klauder University of Florida Gainesville, FL. Dirac on Divergences. - PowerPoint PPT Presentation

Transcript of Field Quantization Without Divergences

Page 1: Field Quantization  Without Divergences

Field Quantization Without Divergences

John R. KlauderUniversity of Florida

Gainesville, FL

Page 2: Field Quantization  Without Divergences

Dirac on Divergences Most physicists are very satisfied with the

situation. They say: 'Quantum electrodynamics is a good theory and we do not have to worry about it any more.' I must say that I am very dissatisfied with the situation, because this so-called 'good theory' does involve neglecting infinities which appear in its equations, neglecting them in an arbitrary way. This is just not sensible mathematics. Sensible mathematics involves neglecting a quantity when it is small - not neglecting it just because it is infinitely great and you do not want it!

.

Page 3: Field Quantization  Without Divergences

Frequently Asked Questions

• No divergences. Is that possible?

YES• What is the ‘‘cost’’?

AN UNUSUAL LOCAL COUNTER TERM• Basic strategy?

SOLVE NONRENORMALIZABLE CASES• Which fields?

SCALARS (HIGGS), [GRAVITY, FERMIONS]

Page 4: Field Quantization  Without Divergences

Outline

• Background (Scalar Fields); Basic Proposal• Free/Pseudofree Models• Why Divergences Arise• How Divergences Appear• Relevance for Scalar Fields• The Cure: ‘‘Measure Mashing’’• Lattice Hamiltonian• Lattice Action• Monte Carlo Evidence• Other Fields• Origin of Measure Mashing

Page 5: Field Quantization  Without Divergences

Background (Scalar Fields)

,6,5 ; 4 ; 3,2 :tionregulariza Lattice

,6,5 ; 4 ; 3,2 :analysison Perturbati

)(

)()()(

)(

)(

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1000

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]})[({)/1(00

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rmscounter te

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Page 6: Field Quantization  Without Divergences

values allfor limit )0( classicalproper

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dependent- an choose tois goal desired The

)(

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)},(])[({)/1( 4

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00

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Basic Proposal

Page 7: Field Quantization  Without Divergences

Free/Pseudofree Models

)()(

lim 0,,

lim

})(])()([{

]})()([{

)2/1(

0

}][{00

00

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F CON.

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Page 8: Field Quantization  Without Divergences

Free/Pseudofree Models

])1(1)[()()(

lim 0,,

lim

})(])()([{

]})()([{

)2/1(

0

}][{00

000

42221

2221

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42221

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AAA

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F CON.

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DISCON.PF

AN “AMPUTATED” ACTION FUNCTIONAL

Page 9: Field Quantization  Without Divergences

Scalar Fields

F REN.

g

NONREN.PF

o

THEORY. A TO CONNECTED

LYCONTINUOUS ARE THEY INSTEAD

.THEORY FREE OWN THEIR TO CONNECTED

ARE THEORIESG INTERACTIN SOME

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}])[({

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40

220

221

0

PSEUDOFREE

NOT

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ng

AN “AMPUTATED” ACTION FUNCTIONAL

B.I.

Page 10: Field Quantization  Without Divergences

Why Divergences Arise

supportdisjoint

)( ; )(

)1( ; )(

measuressingular Mutually

support equal

)( ; )(

/ ; /

measures Equivalent

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B.I.

Page 11: Field Quantization  Without Divergences

Many Variables

; ; support

)(

/)( ;

; ; support

)(

/)( ;

2

111

2

2

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2

)4/1(

1

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l

l

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l lx

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fN

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xN

exdee

dxexdN

exdee

dxexdN

Page 12: Field Quantization  Without Divergences

Support when N = Infinity

if :Hence

lim :order toExpanding

lim :ly Consequent

0||lim

]1[

||||

;

21

1212

4/1

1

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2/12/)(,1,

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4/1

1

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22

2

2

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cN

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NNNN

cNN

icxNjNN

xc

ee

YY

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j

kj

j

Page 13: Field Quantization  Without Divergences

How Divergences Appear

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x

ms!unting terJust by co

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dxexM

pl

Nl

pl

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l

etc. , ][for Also

)()(

][

41

1

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1

2

1

Page 14: Field Quantization  Without Divergences

Relevance for Scalar Fields

' )(

)(12

21'2

21

21

20

2

0

2

2

),,,( :nHamiltonia Lattice

; ; 0 :limit Continuum

;

: withlattice spatial ldimensiona-

cubic-hyper periodic,by Regulate

ks

ks

s

kk

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acinglattice spaach edgesites on eL

s

H

Page 15: Field Quantization  Without Divergences

Ground State Distribution

'

)( )'(

'][][

')(

/'2'2'

/'

2

,

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,

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WILL THE GUILTY VARIABLES THAT LEAD TO DIVERGENCES PLEASE RAISE THEIR HANDS

Page 16: Field Quantization  Without Divergences

Ground State Distribution

dinates rical coorhyper-sphe

LNsDiverges a

ms!No. of terNO

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11 ; 0

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SCOORDINATE OF CHANGEA MAKE

'

)( )'(

'][][

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,

Page 17: Field Quantization  Without Divergences

Moments in the New Coordinates

? HANDS THEIR RAISE PLEASE

SDIVERGENCE TO LEAD THAT

VARIABLES GUILTY THE ILL W

)'(][ toleads which )'(

:integral ofdescent steepest by integral Estimate

)1(2

][

2'2

'2')1'(

22' 2'

,

2

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dd

eaMas

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Page 18: Field Quantization  Without Divergences

Moments in the New Coordinates

! been has every strongly;

variables theseconstrains 1hat relation t The

sdivergence toscontribute that variableONLY theis

)'(][ toleads which )'(

:integral ofdescent steepest by integral Estimate

)1(2

][

2'

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22' 2'

,

2

dneutralize

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dd

eaMa

k

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s

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Page 19: Field Quantization  Without Divergences

Moments in the New Coordinates

!!measures! EQUIVALENT tomeasures SINGULAR

MUTUALLY from measures changes ; DISAPPEAR

sdivergence then , , to Change

.][ : variableONE from arise sDivergence

)'(][ toleads which )'(

:integral ofdescent steepest by integral Estimate

)1(2

][

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2/12'

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,

2

R

NOaNO

dd

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Page 20: Field Quantization  Without Divergences

The Cure: ‘‘Measure Mashing’’

0'2

21' 22

021

22',2

1'221

),,('2/)21(2,

),,(')'(),,(

)1()1'(

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B.I.

Page 21: Field Quantization  Without Divergences

Counter Term

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limit! continuum in the potential localA

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s=2

Page 22: Field Quantization  Without Divergences

Lattice Hamiltonian

83

43

0'2

21' 4

0

' 2202

12',

221'2

21

' )()(

1221'2

21

' ;

4 TO EXTENDED ; 5 BY INSPIRED

)(

)(

* *2

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2

0

2

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ggive e nonnegatSquares ar

E aced by OPering replNormal ord

nn

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H

H

B.I.

Page 23: Field Quantization  Without Divergences

Spacetime and Space Averages

kkpp

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pk

pkk

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k

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k

pk

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skk

dFF

FFa

FFaaF

deaFM

aF

agamF

pp

pp

20

/1

/),,(

40

220

)()()(

|)()(|

|)()(||])([|

])([

])([

} , ,{)(

010010

0100100

0

0

Page 24: Field Quantization  Without Divergences

Lattice Action

gqaNgag

mqaNmam

qaNZahZ

deMe

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spnk k

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)2(30

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)1(22

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)( ][

)(' ][

)( ][

)(

)(),,(

2/12/1

**

F

Page 25: Field Quantization  Without Divergences

Monte Carlo Evidence

ed)(unpublish ,Stankowicz J. Deumens, E. 2.

(1982) 486-481 113B,

n, WeingarteD. Smolensky, P. Freedman, B. 1.

1)( ; 1 ; 63.3 : parametersChosen

)0(~/])0(~3)0(~[)(

: constant coupling edRenormaliz

|)(~|/]|)(~|)0(~[

: mass edRenormaliz

)/2,,0,0( ; )(~

:onansformatiFourier tr Discrete

22224

22222

.Phys. Lett

Lam

Lamg

g

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m

Lapep

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nRR

R

R

R

kkkaip

Page 26: Field Quantization  Without Divergences

g_R vs. g_0 for n=3 and n=4

Page 27: Field Quantization  Without Divergences

Phi^4_4 With Counter Term

Page 28: Field Quantization  Without Divergences

Other Fields

bosons gauge NO

only) sindicationfar (So :Fermions

0)( , )( ; )()( )(

Gravity) Quantum (Affine :Gravity

][ ; ][ ; )(

},,2,1{ ; :fields like-Higgs2,,

',

'2,

2,,,,

,

**

bab

aabcb

acab

llklkp

k kkkkk

kk

uxguxgxgxx

J

A

Page 29: Field Quantization  Without Divergences

Origin of Measure Mashing

ytion theorr perturba cutoffs oed without Both solv

xddtMgmiA

xddtgmA

s

s

'mashing' measure'' of) (analog toleadmay

})({

! 1973in Solved

2008in 'mashing' measure'' toled

}][{

! 1970in Solved

2200

440

220

221

Page 30: Field Quantization  Without Divergences

Ultralocal Scalar Fields

NbaR

ambam

deM

defba

dexfxdbfC

edeMfC

and

xddtxtgxtmxtA

sRN

ss

kkba

kkamafi

babmk

sk

bmspf

xdxfmkk

amafif

sg

ss

kk

s

kkk

s

ss

kk

s

kkk

2 ; :y Effectivel

; : Note

][

}||/)]cos(1[)(1{

}||/)])(cos(1[exp{)(

)(

! Trivial lizableNonrenorma

}),(]),(),([{

)1()1(

0

2/)21(2

)21(

)()4/1(

40

220

221

2

0

2

2

2

0

2

0

Page 31: Field Quantization  Without Divergences

Summary

• Lattice ground state wave function ‘‘=’’ Lattice Hamiltonian ‘‘=’’ Lattice action

• Origin of divergences traced to power of the hyper-spherical radius

• Measure mashing changes mutually singular measures into equivalent measures

• Finite spatial moments implies finite spacetime moments

• Monte Carlo supports non-triviality

2/12]'[ kk

Page 32: Field Quantization  Without Divergences

Feynman on Divergences .

The shell game that we play ... is technically called 'renormalization'. But no matter how clever the word, it is still what I would call a dippy process! Having to resort to such hocus-pocus has prevented us from proving that the theory of quantum electrodynamics is mathematically self-consistent. It's surprising that the theory still hasn't been proved self-consistent one way or the other by now; I suspect that renormalization is not mathematically legitimate.

Page 33: Field Quantization  Without Divergences

Thank You

Page 34: Field Quantization  Without Divergences

References

• ``Scalar Field Quantization Without Divergences In All Spacetime Dimensions'' J. Phys. A: Math. Theor. 44, 273001 (2011); arXiv:1101.1706

• ``Divergences in Scalar Quantum Field Theory: The Cause and the Cure'', Mod. Phys. Lett. A 27, 1250117 (9pp) (2012); arXiv:1112.0803

• Ultralocal model scalar quantum fields: ‘‘Beyond Conventional Quantization’’ (Cambridge, 2000 & 2005)

• ‘‘Recent Results Regarding Affine Quantum Gravity’’, J. Math. Phys. 53, 082501 (19pp) (2012); arXiv:1203.0691