Теории / Садовский М.В. Диаграмматика (2005)
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Hint g d ψ ψ ϕ
g $ ( $ % ! & 8 ! # I&
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G0(p) = |
δαβ |
δ → +0 |
I&I |
ε − ξ(p) + iδsignξ(p) |
!
p2
ξ(p) = 2m − µ ≈ vF (|p| − pF ) I&J $ ( % ! (
* N ! ! µ pF vF $ ! * # #
N ! &
•:/- %* # $ % %* 8 W
D0(k) = |
ω02(k) |
δ → +0 |
I& |
ω2 − ω02(k) + iδ |
•G n ! ! ! * # ! ! J$! * # ! &
•. * # *! (%% (g)2n(2π)−4n(i)n(2s + 1)F (−1)F F
$ ! * % ! # s $ % ! ( s = 1/2 % * 2s + 1 = 2 &
G T > 0 W
•K ( ! * # ! p ! *
εn = (2n + 1)πT W
G0(εnp) = |
δαβ |
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iεn − ξ(p) |
I& |
F 9 CC D
• K % * ! * # ! k ωm = 2πmT
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ω02(k) |
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D0(k) = − |
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I&Q |
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ωm2 + ω02(k) |
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ω0(k) |
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ϕ(k) = |
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(bk + b−k) |
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2 |
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ϕ(k) = bk + b−+k |
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6 ' 1 . " ' ? = |
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D0(kω) = |
1 |
− |
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1 |
= |
2ω0(k) |
( )*+ |
ω − ω0(k) + iδ |
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ω + ω0(k) − iδ |
ω2 − ω02(k) + iδ |
2 " 8
" % % 3 ' % 8
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" ( ,+ ( 7+ 8
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Hint = g¯k ap++kap(bk + b−+k) |
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pk |
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I ( H+ = |
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Hint = g |
ω0(k) |
a |
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ap(bk |
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−k |
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pk |
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% 3 ' > 8
! !
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ζ = g2νF |
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-0 = |
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2¯g2 |
νF |
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λ = |
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ω0(k) |
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( ))+ ( )7+ = |
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g¯k = g |
ω0(k) |
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2 |
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> )
$ ( (
( * ! ( $ % ! & 6
% * ) % %* 8 D(ωk)& K %* 8 ( G(Ep) % %* 8 !
$ ( %
! ! Π(ωk) ! ( $ %
! ( . & I&,& M 6 %
/ ' % "
( )+ ( H +
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. & I&,W 8 % $ ( % &
%* 8 ! W |
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D(ωk) = D0(ωk) + D0(ωk)g2Π(ωk)D(ωk) |
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! W |
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D−1(ωk) = D0−1(ωk) − g2Π(ωk) |
I&,Q |
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' % * !W |
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D0−1(ωk) = g2Π(ωk) |
I&,L |
X ! *) * ( $ % ! |
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ζ = g |
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νF νF = |
2π2 3 # * N ! |
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2 |
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mpF |
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* ) ζ 1& G (
!* # # ( % ! #
& 4 ! * ! ! ! * *
# ! ! )
! g& ! !
EF |
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M 1 # ωD m $ ! ( M $ ! |
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ωD |
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m |
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& 6 ! * # ! ) !
( & ' ( ! * 1 #2 *
! ( 1 ) 2 # *) % * )& 3 * !
* # ( $ % ! * )
% ! &
) * % ' %
. ! ! +I- $ ( *) # (
! % ! . & I& & ' *)
! * ! * ! % ! W
Σ(Ep) = (2π)4 |
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E − ω − ξ(p − k) + iδsignξ(p − k) ω2 |
− c2k2 |
+ iδ |
I&,O |
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ig2 |
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dωd3k |
c2k2 |
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/ # ! ) ) ω1 = E − ξ(p − k) + iδsignξ(p − k) ω2,3 = ±(ck − iδ)&
3 ! * # * * #
) % %* 8 & H *
* * * #& ' ( !
* !W
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−g |
2 |
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3 |
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k |
2 |
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3 |
2 |
k |
2 |
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Σ(Ep) = |
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d k |
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c |
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− |
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d k |
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c |
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(2π) |
3 |
ξp−k<0 |
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ξp−k>0 E − ck − ξ(p − k) + iδ 2ck |
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E + ck − ξ(p − k) − iδ (−2)ck |
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= |
g2c |
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kd3k |
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+ ξp−k<0 |
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kd3k |
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= |
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16π3 |
ξp−k>0 |
E − ck − ξ(p − k) + iδ |
E + ck − ξ(p − k) − iδ |
F L ? 2 ? |
Q |
. & I& W G $ ( *) # ( (
$ % ! &
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g2c |
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kd3k |
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+ |
kd3k |
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16π3 |p−k|>pF E − ck − vF (|p − k| − pF ) + iδ |
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|p−k|<pF E + ck − vF (|p − k| − pF ) − iδ |
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( 7*+ |
S ! x * * ! * ! k p ! ! p2 |
= p |
k 2 = |
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p |
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+ k |
2 |
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3 |
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1 |
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− 2pkx d k |
= 2πk |
dkdx p1dp1 = −pkdx& 5 I& |
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W |
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Σ(Ep) = − |
g2c |
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k2dkdp1p1 |
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+ p1<pF |
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k2dkdp1p1 |
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( 7)+ |
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8π2p |
p1>pF |
E − ck − vF (p1 − pF ) + iδ |
E + ck − vF (p1 − pF ) − iδ |
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S # # ) ! |
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# p1 |
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p |
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pF # * ωD EF & G ( !* ! # ! p1 |
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p |
#W |
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≈ |
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≈ |
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Σ(E) = − |
g2c |
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k2dkdp1 |
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+ p1<pF |
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k2dkdp1 |
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( 77+ |
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8π2 p1>pF E − ck − vF (p1 − pF ) + iδ |
E + ck − vF (p1 − pF ) − iδ |
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5 ! ! Σ(E) * !W |
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ImΣ(E) = |
g2c |
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δ(E − ck − vF (p1 − pF ))k2dkdp1 − p1<pF δ(E + ck − vF (p1 − pF ))k2dkdp1 |
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8π |
p1>pF |
( 7 +
G ! # * E > 0 ! (
* E < 0 $ ! & . ! ! #
# * E ωD E ωD&
• ' * E ωD
G E > 0 # I& I k *
# k < E/c p1 ! *! ! δ%*
! # pF & G ( !* ! !W |
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ImΣ(E) = 8π |
ck<E vF k2dk = |
24πvF c3 |
I& J |
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g2c |
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1 |
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g2cE3 |
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! *) * ( $ % ! ζ |
= g2νF |
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* !W |
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ImΣ(E) = |
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ζπE3 |
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12p2 c2 |
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I& |
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F |
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L |
. F - >JK<= L G<=<==< M/0 <1 N J 0 |
G E < 0 # I& I &
* ! I& $ ( !!
E EF ! ! # ImΣ(E) %* E&
! E → 0 ! ! ImΣ(E) E ( $ % !
/ % ! *) * ! * E3 !
* # % E → 0 !
) * ! * ! ( $ (
E2 & ! ( * # E → 0T → 0 &
• ' * E ωD
( ! * p1 I& I #
k # # k = kD &
I& J * !W
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g2 |
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k3 |
g2k3 |
mc |
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ImΣ(E) = |
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c |
D |
signE = |
D |
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signE |
I& |
8πvF |
3 |
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24πpF |
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# * ! *) * ζ ! !W
ζπk3 c
ImΣ(E) = D signE I& Q
12p2F
4 * # ! ImΣ ζωD & 5 ! ! ζ 1 % ! ! * ωD EF &
G ! # * ReΣ(E)& H I& ! !W
ReΣ(E) = − |
g2c |
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k2dkdp1 |
+ |
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k2dkdp1 |
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= |
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8π |
2 |
>pF |
E − ck − vF (p1 − pF ) |
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p1 |
p1<pF E + ck − vF (p1 − pF ) |
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g2c |
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= − |
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k<kD dkk2I1 |
(k) ( 7H+ |
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8π2 |
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E − ck − vF (p1 − pF ) + |
p1<pF |
E + ck − vF (p1 − pF ) |
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I1(k) = p1>pF |
I& O |
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dp1 |
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dp1 |
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N ! # ( ! # %
# * # p1 p * * # (
# * ! ! *)
* & G ( !* ! # p1 = p pF &
5 ( ! *
# ! ! * ReΣ(0) & 5 ! ! * !W
1 |
(k) = |
vF |
E + ck + vF pF |
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vF |
ln |
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E |
− |
E ck |
− |
pF ) |
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1 ln |
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E + ck |
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ck − vF (p |
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− |
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! * ! δµ = Σ(0) * !W
Re(Σ(E) |
− |
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8π2 |
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pF |
E + ck |
I&I, |
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Σ(0)) = g2c |
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dkk2 m ln |
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E − ck |
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F L ? 2 ? |
O |
U # $ ( ( *
( $ % ! ! ! ^ * ! ! * # p& 1! #)2 % ) ( !
# * & . ! ! #
E ωD E ωD &
•' * E ωD
( ! * ! %! I&I, # E ck& 5 ! !W
Re(Σ(E) − Σ(0)) = − 8π2pF |
0 |
dkk = − |
8π2pF |
E = −4 pF2 |
E ≡ −λE I&I |
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2mg2E |
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kD |
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mg2k2 |
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ζ k2 |
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D |
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* ! λ = |
ζk2 |
ζ& |
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D |
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4pF2 |
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• ' * E ωD
5 # ! ! E ck ! %! I&I, * !W
Re(Σ(E) − Σ(0)) = −4π2pF 0 |
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E |
= −16π2pF E |
= − 8pF2 |
E |
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mg2c2 |
kD k3dk |
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mg2c2k4 |
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ζc2k4 |
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D |
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D |
E ωD ReΣ(E) ( ! * !& ' E ωD ! * W
E − ξ(p) = Re(Σ(E) − Σ(0))
ξ(p) = p2 − µ& 5 * * !W
2m
E = |
p2 |
EF = |
p2 |
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− EF |
F |
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2m |
2m |
(%% ! W
m = 1 + ζkD2 ≡ 1 + λ m 4p2F
I&II
I&IJ
I&I
I&I
G ( !* *) ! ! λ ! # !
! & 5 ! ! ( ! % ! (%%
1* 2& ' 1 2 # * N ! ( m ) ( ! #&
. ! ! # ( (
! * & ! # * ( ! ! * !
! *!! ! * ! !& H! !W
Σ(εp) = −(2π)3 |
ε1 |
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d3p1G(ε1p1)D(ε − ε1, p − p1) |
I&IQ |
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g2T |
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# ! * ]
Q |
. F - >JK<= L G<=<==< M/0 <1 N J 0 |
. & I&IW K * # * ! *!! ! *
! !&
S ! *!! ! * ! ! #
*) ! +-& . ! ! * *!! ! % ! ! ! iεn = i(2n + 1)πT & ' *) *) *!!* ! #
* ! εW
∞ |
F (iεn) = − |
1 |
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F (ε) |
1 |
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F (ε) |
1 |
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ε |
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T n= |
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2πi C dε eβε + 1 |
= 2πi |
C dε e−βε + 1 = |
4πi |
C dεF (ε)th 2T |
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−∞ |
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I&IL |
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* C * ! !*) # ( . & I&I |
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* ) %* F (ε)& |
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' # I&IL |
! K # eβε + 1 |
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e−βε + 1 β |
= |
1 |
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ε = iεn |
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T |
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! ) * |
* ) *) ) #
I&IL |
*) ! ! & : * |
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# th |
ε |
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2T |
! I&IL & |
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6 *!! ! ! |
! iωm |
= i2πT m ! |
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# # ! !W |
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∞ |
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1 |
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F (ω) |
1 |
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F (ω) |
1 |
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ω |
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T m= |
F (iωm) = 2πi |
C dω eβω − 1 |
= −2πi C dω e−βω − 1 |
= 4πi |
C dωF (ω)cth 2T |
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−∞
I&IO
) # iωm = i2πT m& 6 # ! ! * C
1 2 # ( ! ) )
%* F (ε) F (ω) 1 * 2
* C& # * ) *
* * F (ε) F (ω) ( ! * &