PHYSICAL
V O L U M E 39, N U M B E R 2
REVIEW
LETTERS
11 J U L Y
1977
Critical Exponents for the /i-Vector Model in Three Dimensions from Field Theory J. C. L e Guillou Laboratoire
de Physique
Theorique
et Hautes Energies,
Universite
Paris
VI, 75230 Paris
Cedex 05,
France
and J. Zinn-Justin Service
de Physique
Theorique,
Centre
d* Etudes Nucleaires de Saclay, (Received 14 April 1977)
91190 Gif-sur-Yvette,
France
We present a new calculation of the critical exponents of the η-vector model through field-theoretical methods. The coefficients of the renormalization functions of the (φ ) theory are expanded in powers of the coupling constant. Asymptotic estimates of large order of perturbation series are used to transform the divergent perturbation series into a convergent one. As a consequence, new and more precise values of critical exponents are obtained. 2 2
Initiated by Wilson, the field-theoretical ap proach to critical phenomena has been e x t r e m e ly successful in the domain of phase transitions. In particular, it has been possible to calculate physical quantities such as critical exponents through the famous Wilson- Fisher e = 4 - d ex pansion. M o r e recently, use has been made of perturbation s e r i e s for the g
2
T A B L E I. Perturbative expansion (Ref. 8) of renor malization-group functions of the gUp ) field theory with Oin) symmetry in three dimensions. 2 2
η - 1 W(g)
= - g + g -
3
Y
_ ,
(g)
0.376526828 g
-
1 ~ I
A
- 0.4224965707 g
2
-
g + 27"
0.02245952
•
0.3510695978 g
+ 0.49554751 g
5
g
3
'
2
4
- 0.749689 g
6
7
0.0230696213 g +0.0198868203 g 3
g
5
+ 0.0303679
0.0109739369 g
2
+ 0.0009142223 g *0.0017962229 g
g
4
6
4,5
6
2
N(g)
-
W(g)
0.00065370 g
- -
g + g
3
+ 0.0013878 η « 2
5
- 0.4029629630 g
2
g
6
• 0.3149169420 g
3
4
4
7
Y
_ 1
(g)
0.317928484 g
-
1 - { -
2
N(g)
-
g + 2l g
0.02219865
+ 0.39110247 g
5
g
2
7
~ 0.0259419075 g +0.0205323538 g 3
+ 0.0279829
5
- 0.552448 g
6
g
0.01185l8519g + 0.0009873601 g 2
4
6
+ 0.0018368107 g
3
4
8
-
W(g)
0.00058633 g
= - g + g
+ 0.0012514 η = 3
5
- 0.3832262015 g
2
g
6
+ 0.2829466813 g
3
4
9
The main ingredient that w e shall use in the analysis of the perturbation s e r i e s i s the follow ing: It can be shown ' that in the g(
7
A(g)=EKA g\ K
Y~'(g)
N(g)
K
+ 0.31255586 g
5
ΤΤΓ
+
g
G
0.0122436486 g - 0.00050410 g
" °-
0 2 7 6 6 7 3 0 1
2
7
9g *0.0201190591 g 3
g
3
g
4
6
+ 0.0010200001 g «0.0017919258 g
+ 0.0010883
5
- 0.414861 g
6
4
6
η - ρ -
-
(2)
2
·»• 0 . 0 2 4 7 4 9 7
5
(1)
where a and b have been calculated in three di mensions for the various renormalization-group 7
8
0.02101293
-
behave f o r large Κ (K-~+<») as K
1 " j2
-
2 2
W(g)
A ~K\{-a) K\
0.270333298 g
γ"'( ) 8
•
2 g
- 0.4398148149 g
0.447316097 g 1 - 1 g + JL
= -
H(g)
g
-
0.02062072
0.00066062 g
5
-
6
1.034928
4
g
7
- 0.0184623402 3+0.0172838882 g
g
4
g
+ 0.0299914
5
0.0092592593 g -
• 0.3899226895 g
+ 0.63385550 g
5
2
g
3
2
g
6
+ 0.0007713750 g +0.0015898706 g 3
• 0.0014103
g
4
6
95 CPSC
7 - paper 61
527
PHYSICAL
V O L U M E 39, N U M B E R 2
functions
etc.].
v(g),
REVIEW
T h e p r e s e n c e of a A !
b e h a v i o r had b e e n anticipated b y B a k e r et a/.,
LETTERS
11 J U L Y 1977
the structure of the n e a r e s t singularity of B(g). Under the assumption that B{g) i s analytic in a
5
w h o used the P a d e - B o r e l method to sum the s e r
cut p l a n e , it i s p o s s i b l e to map the cut plane on
i e s and obtain v a l u e s f o r the c r i t i c a l exponents
a c i r c l e and obtain a convergent e x p a n s i o n
for I s i n g - l i k e s y s t e m s (n = 1 ) .
B(g)—and
T h e m o r e complete
information now a v a i l a b l e a l l o w s us to apply a m o r e p r e c i s e method.
t h e r e f o r e A (g)—so
10
for
that
A&^f^e-'B^dt.
Defining the B o r e l t r a n s
f o r m of A(g) by
(4)
A s shall b e explained b e l o w , this method can b e
Β®=Σκ(Ακ/ΚΙ)Ζ ,
(3)
Κ
w e can determine f r o m E q . (2) the position and
Δ
further refined with u s e of the known coefficient b of E q . ( 2 ) , |
O u r b e s t e s t i m a t e s f o r the c r i t i c a l
exponents a r e p r e s e n t e d in the following t a b l e :
η
1
2
3
0
g* γ η ν ω
1.414±0.003 1.2402± 0.0009 0.0315± 0.0025 0.6300± 0.0008 0.782± 0.010 0.493± 0.007 0.325± 0.001
1.405±0.002 1.3160± 0.0012 0.0335± 0.0025 0.6693± 0.0010 0.778± 0.008 0.521±0.006 0.346± 0.001
1.391±0.001 1.3866± 0.0012 0.0340± 0.0025 0.7054± 0.0011 0.779± 0.006 0.550±0.005 0.3647± 0.0012
1.4170 ± 0.0045 1.1615± 0.0011 0.0260± 0.0030 0.5880*0.0010 0.790± 0.015 0.465±0.010 0.3020± 0.0013
ων
1 }
β
H e r e , g* i s the fixed-point value of the r e n o r m a l i z e d coupling constant, n o r m a l i z e d in such a w a y that W(g) = -g+g +0(g ), 2
f o r the field and Ζ (g) W(g)
tical exponents w h i c h g o v e r n the b e h a v i o r n e a r the critical t e m p e r a t u r e T
f o r the v e r t e x b y
(4)
and γ and ν a r e the c r i
3
= (d-4)[dlng /dg]'\
g =gZ /Z . 0
0
of the magnetic s u s
Z
ceptibility χ and of the c o r r e l a t i o n length ξ , r e
φ
spectively, such that
a r e d e t e r m i n e d b y the functions
c
( 2 ) 2
b e i n g the r e n o r m a l i z a t i o n constant f o r the i n s e r t i o n , the c r i t i c a l exponents η, ν, and γ
(5)
v(g)
=
The exponent 77 g i v e s the l a r g e - d i s t a n c e b e h a v i o r
v{g)
= [2 + W(g)d lnZ /dg
Y(g)
=
k~\T-T \'\
x~|t-T |-7,
c
c
at T
of the s p i n - s p i n c o r r e l a t i o n function G(*r)
c
~χ ~ ~ , 2
α
η
and ω g o v e r n s the leading c o r r e c t i o n s
(6)
2
{4)
2
W(g)[dlv>Z(g)/dg], (2)
- v(g)],
(7)
v(g)[2-V(g)],
evaluated a t g =g*, i . e . ,
to scaling. O u r r e s u l t s f o r the c r i t i c a l exponents in the c a s e with n = 1 a r e c o m p a t i b l e with, but m o r e
*7 =*?(£·*),
v = v(g*)>
y=r(^*)-
(8)
p r e c i s e than, those obtained in Ref. 5: γ = 1.2410
F i n a l l y , the leading c o r r e c t i o n s to the scal i n g
± 0 . 0 0 2 ; 77 = 0 . 0 2 1 ± 0 . 0 2 ; ν = 0.627± 0.01; u> = 0.78
l a w s a r e g o v e r n e d b y the exponent
± 0 . 0 1 ; and Δ = 0.49± 0.01. Α
O u r results give also
m o r e p r e c i s e v a l u e s than the most r e c e n t h i g h temperature-series estimates
11
and a r e in a g r e e
L e t u s denote b y A^Hg),
ment with them, even now f o r the exponent γ a l
tions W(g),
though the v a l u e i s definitively l o w e r than the c e n
tively.
t r a l value given b y h i g h - t e m p e r a t u r e s e r i e s . O u r r e s u l t s a r e a l s o in v e r y good a g r e e m e n t with the most r e c e n t e x p e r i m e n t a l r e s u l t s
1 2
(see Table II).
(9)
u>=W'(g*).
W'(g),
U)
K
K
w h e r e the coefficients A the other functions.
2
z e r o g* of the r e n o r m a l i z a t i o n - g r o u p function W(g)
of the gfcp (x)] 2
2
field theory, which i s d e
fined through the r e n o r m a l i z a t i o n constants Ζ (g) 96 528
CPSC
7 - paper 61
^ have b e e n calculated
u p to Κ = 7 f o r W(g) and u p to Κ = 6 f o r
to d e r i v e these r e s u l t s .
The c r i t i c a l b e h a v i o r of a s e c o n d - o r d e r p h a s e
respec
(10)
A (g)=B A ^g\ by N i c k e l
transition i s g o v e r n e d b y the i n f r a r e d - s t a b l e
the f u n c
andy(^),
T h e i r perturbation expansion i s
W e shall b r i e f l y sketch the method which w e u s e d 1 3
for i = 1-5,
η(&), v(g),
8
It has recently b e e n s h o w n
that the asymptotic b e h a v i o r of A ^ K
l)
7
for large Κ
i s given b y A^~K\(-a) K (i)C [l+0(l/K)], K
b
(i)
(11)
w h e r e the n u m e r i c a l v a l u e s of a and b a r e a s f o l -
PHYSICAL
V O L U M E 39, N U M B E R 2
REVIEW
T A B L E Π. Comparison of our results (first column) with those of Baker et al. (second column; Ref. 5 ) , ex perimental data (third column; Ref. 1 2 ) , and high-tempperature-series results (fourth and rightmost column; Ref. 1 1 ) .
LETTERS
B (gt)
11 J U L Y 1977
of the function A (g)
{i)
(i)
/ °°
Ξ
π
1 240±0.007
1.24110.002
1.2402±0.0009
Y
» 1
1 .23
1.24
1 .27
1.28
a
o
by writing
e'H 'B^{U)dt,
(13)
b
where b' will be varied in the neighborhood of b and where U=gt The important point is that the behavior (11) for large Κ gives the location and the nature of the nearest singularity of the Borel transform B (U). This singularity is located at £ / = - l / a , where B (U) behaves as (1 + aU) ' "\ or as l n ( l + all) for b' = b + 1 . Assuming that B (U) is analytic in the i/-plane cut f r o m - 1/a to - o o , we can now map this cut plane into a c i r cle in the χ plane with 0
1
e
250 °· *^ -0.007 +
1
0 0 3
υ
(i)
0.021±0.02
η 0.0315±0.0025
0. 016±0.007 0 016±0.014
ν 0.6300±0.0008
0.627±0.01
0. 625±0.003 0. 625±0.005
0.320±0.016
6 0.325 ±0.001
0 . 321
0.323
(i)
a
°·
a
b
e
U=x(l-iax)' =
328±0.004
n=
c
U x",
(14)
n
1
the integration in (13) running f r o m x = 0 to χ = 4/α. The B o r e l transform is now given in (13) through a convergent s e r i e s in x, which leads to
n = 2
0. 675±0.001
Σ
2
316±0.008
0.
ν 0.6693±0.0010
(i)
f
0.312±0.005
0.329 0.
..Ο+0.002 -0.008
6 3 8
b mb
d
Α \)=Σ„ΰ (
n = 3
η
{ f~e'
Ψ\x(t)]»
dt}.
(15)
c
We have first used this result to calculate the z e r o g* of W(g). We have done this by several methods. One method consists of calculating the z e r o g* of W(g) for different number of terms of the new expansion (15). Because the successive values of g* seemed to converge v e r y smoothly, we extrapolated them with use of Pad6 approximants. Another approach used was to write W{g) as -gF(g) o r -g+g F(g), and then apply our method on the F(g) This latter method seems to converge faster than the f o r m e r one and, without the use of any Pad§ extrapolation, yields precise values of g* which are consistent with those ob tained from the other methods. In each case, we have varied b' in a neighborhood of b in order to generate a function B(U) with a weak singularity
f
[(l + aU) ,
1
375 °· -0.01 +
g
0 2
, , J / ; >
Υ
1.3866±0.0012
η
0.0340±0.0025
1.405±0.02
h
i
1 42 ° · ^ -0.01 +
1 ,
ν 0.7054±0.001 1
2
0.043±0.0l4
g
0.040±0.008
h
0 U
0
Ζ
'
7025 °· -0.005 +
g
0 1 0
/ U O
2
a
b
c
d
0.717±0.007
h
0.725±0.015
1
0
Chang et al., Ref. 12. Hocken and Moldover, Ref. 12. G r e e r , Ref. 12. Mueller et al., Ref. 1 2 ; Grey wall and Ahlers, Ref.
12.
C a m p et al., Ref. 1 1 . Domb, Ref. 1 1 . ^Ritchie and Fischer, Ref. 1 1 . F e r e r et al. Ref. 1 1 . ^Camp and Van Dyke, Ref. 1 1 .
h
1/2
t
« = 0.147 774 2 2 . . . ,
b
(i)
w(g);
= j 3 + i w f o r W{g)Mg)Mg)\ ( 2 + i w for
(1 + aU)' ] l/2
at U= - 1/a.
{i)
lows:
{ 5 + i n for
ln(l+fl£/),
This has given us a range of values for g*, for which we have calculated the other quantities A (g), again with application of the same meth ods as for Wig).
(12)
T){g).
We introduce the generalized B o r e l transform
We have made other checks like calculating ex ponents f r o m the direct s e r i e s and its inverse, and verified the scaling laws 2/9 = 3i/ - y and γ = i/(2 - η) between the independently computed e x ponents. A l l the results that we have obtained are consistent with one another. Finally, several advantages of our approach with respect to the Pad6-Borel method are to be emphasized. F i r s t , it gives more stable and a c 97 CPSC
7 - paper 61
529
P H Y S I C A L
V O L U M E 39, N U M B E R 2
R E V I E W
curate v a l u e s , as w e have v e r i f i e d , f o r instance,
diate coupling, the a c c u r a c y i s , f o r s i x t e r m s of the p e r t u r b a t i o n s e r i e s , of the o r d e r of 1 0 * f o r
11 J U L Y 1977
don and B r e a c h , N e w Y o r k , to b e p u b l i s h e d ) .
on the calculation of the g r o u n d - s t a t e e n e r g y of the anharmonic o s c i l l a t o r w h e r e , f o r an i n t e r m e
L E T T E R S
G. A. Baker,
5
Meiron, G
B. G. Nickel,
M . S. G r e e n ,
and P . I.
P h y s . R e v . L e t t . 36, 1351 ( 1 9 7 6 ) .
L . N. Lipatov,
P i s m a Z h . E k s p . T e o r , F i z . 2 5 , 116
(1977) [ J E T P L e t t , (to b e p u b l i s h e d ) ] , L e n i n g r a d I n s t i
2
the Pade" method, 1 0 " f o r the P a d 6 - B o r e l m e t h 3
od,
and 3 x l 0 "
4
tute of N u c l e a r P h y s i c s R e p o r t s N o . 253 and N o . 255, 1976 (to b e p u b l i s h e d ) .
f o r our method. Second, to i m
p r o v e efficiently the rate of c o n v e r g e n c e of a s e r
7
i e s by m e a n s of the P a d e * - B o r e l method, the p e r This
condition is not c r u c i a l in o u r a p p r o a c h .
This is
p a r t i c u l a r l y important in the calculation of c r i t i cal exponents f r o m φ field theory in t h r e e d i 4
5
and v (g)=W(g)(d/dg)ln[z (g)], 2
only u s e d 1/γ(&) whose series a l
{2)
8
B . G . N i c k e l , to b e p u b l i s h e d .
Our Table I gives
numbers used h e r e .
turbation s e r i e s has to alternate in s i g n .
mensions, w h e r e B a k e r et al.
E . B r e z i n , J . C . L e G u i l l o u , and J . Z i n n - J u s t i n ,
P h y s . R e v . D 15, 1544, 1558 ( 1 9 7 7 ) .
ternate in sign, the other c r i t i c a l exponents being
9
P . G . de G e n n e s ,
Cloizeaux,
P h y s . L e t t . 4 4 A , 271 ( 1 9 7 3 ) ; J . d e s
P h y s . R e v . A 10, 1665 ( 1 9 7 4 ) , and J . P h y s .
( P a r i s ) 36, 281 ( 1 9 7 5 ) . Rep. 1 0
S e e a l s o D . S. M c K e n z i e ,
J. J. Loeffel,
C e n t r e d ' E t u d e s N u c l e a i r e s de S a c l a y
Report No. S A C L A Y - D P h - T / 7 6 - 2 0 ! 1
Phys.
2 7 C , 35 ( 1 9 7 6 ) . (unpublished).
W . J. C a m p , D. M . Saul, J. P. Van Dyke,
and
obtained by s c a l i n g r e l a t i o n s . With o u r method,
M. Wortis,
w e could calculate a l l exponents independently.
and J . P . V a n D y k e , J . P h y s . A 9 , 731 ( 1 9 7 6 ) ; C . D o m b ,
W e a r e e x t r e m e l y grateful to G. A . B a k e r , B . G. N i c k e l , and D. I. M e i r o n f o r communicating to us,
p r i o r to publication, the T a y l o r s e r i e s listed
in T a b l e I.
W e e s p e c i a l l y thank B . G. N i c k e l f o r
c o r r e s p o n d e n c e concerning these n u m b e r s .
P h y s . R e v . Β 14, 3990 ( 1 9 7 6 ) ; W . J . C a m p
in Phase Transitions
1 9 7 4 ) , V o l . 3; M . F e r e r , Fisher, l 2
E . B r e z i n , J . C . L e G u i l l o u , and J . Z i n n - J u s t i n ,
Phase Transitions
P h y s . R e v . Β 4 , 3184 ( 1 9 7 1 ) .
and Critical
Phenomena,
C . D o m b and M . S. G r e e n ( A c a d e m i c ,
edited b y
New York,
1976),
Vol. VI. 3
K . G . W i l s o n and Μ . E . F i s h e r , G. Parisi,
P h y s . R e v . Lett. 28,
P h y s . R e v . L e t t . 3 7 , 29 ( 1 9 7 5 ) ; S. C .
P h y s . R e v . A 14, 1770 ( 1 9 7 6 ) ; Κ. H . M u e l l e r , P h y s . R e v . L e t t . 34, 513
( 1 9 7 5 ) ; D . S. G r e y w a l l and G . A h l e r s ,
P h y s . R e v . A 7,
2145 ( 1 9 7 3 ) . 1 3
A p p l y i n g the s a m e m e t h o d f o r d = 2 and η = 1 ( I s i n g
η = 0.19±0.07.
y = 0 . 9 8 ± 0.07, and ω = 1.1 ± 0 . 3 .
1
In t h i s
c a s e the p e r t u r b a t i o n s e r i e s h a s o n l y b e e n c a l c u l a t e d in P r o c e e d i n g s of the 1973 C a r g e s e
m e r S c h o o l , edited b y E . B r e z i n and J . M . C h a r a p
98 530
E.
m o d e l ) w e h a v e found g* = 1.85 ± 0.07, y = 1.79 ± 0 . 0 7
240 ( 1 9 7 2 ) . 4
M . A . M o o r e , and M . W o r t i s ,
P h y s . R e v . L e t t . 37, 1481 ( 1 9 7 6 ) ; R . H o c k e n and
F . P o b e l l , and G . A h l e r s , in
edited York,
R . F . C h a n g , H . B u r s t y n , J . V . S e n g e r s , and A . J .
Greer, K . G. Wilson,
r
New
P h y s . R e v . Β 5, 2668 ( 1 9 7 2 ) .
M . R. Moldover, !
Phenomena
P h y s . R e v . Β 4 , 3954 ( 1 9 7 1 ) ; D . S . R i t c h i e and Μ .
Bray,
2
and Critical
b y C . D o m b and M . S. G r e e n ( A c a d e m i c ,
CPSC
7 - paper 61
Sum (Gor
( R e f . 8) up to o r d e r 5 f o r W(g) other functions.
and to o r d e r 4 f o r the