fizyka statystyczna


V
Ni(i = 1, 2, ..., N)
U V
N1, N2, ..
 t 
t 
dW = -P dV,
d W d W
W
dQ = dU - dW = dU + P dV.
U, V, Ni S
U
U1, U2
S h1, h2 S
S =
S(U, V, Ni)
S = S(U, V, Ni)
S(U, V, Ni) = S(U, V, Ni),
"S
> 0,
"U
V,Ni
S
U, V, Ni
U = U(S, V, Ni),
U
("U/"S)V,N = 0.
i
n
"U "U "U
dU = dS + dV + dNj.
"S "V "Nj V,S
V,Ni S,Ni j=1
"U
a" T,
"S
V,Ni
"U
- a" P,
"V
S,Ni
"U
a" i.
"Ni V,S
T P
1 "V
a" ą,
V "T
P
1 "V
- a" T ,
V "P
T
T "S 1 d Q
= a" CP ,
N "T N dT
P P
T "S 1 d Q
= a" CV .
N "T N dT
V V
ą T
CP CV
U = -U(S, V, Ni)
T = T (S, V, Ni),
P = P (S, V, Ni),
i = i(S, V, Ni).
(T, P, i)
T (S, V, Ni) = T (S, V, Ni).
dU = T dS - P dV, dQ = T dS,
U S
U
S N (U, S, V, N)
 
(h, S, V , Ń)
N N , N Ń,

V = V + V = const

S = S + S = const,
 
dV = dV + dV = 0 i dS = dS + dS = 0 dU = dU + dh.
"U "U "h "h
 
dU + dh = dS + dV + dS + dV
 
"S "V
"S "V
dS  

= T dS - P dV + T - pdV .

S = S + S = const
 
dS = -dS, dV = -dV ,
)dS )dV
(T - T - (P - P = 0.
S, V
, .
T = T P = P
d2U > 0.
d2U = USS(dS)2 + 2USV dSdV + UV V (dV )2
"2U "T
USS = =
"S2 "S
"P "T
USV = UV S = - = ,
"S "V
"P
UV V = -
"V
f(x, y) = A(dx)2 + B(dy)2.
A B
dT = USSdS + USV dV.
2
USV
-1
d2U = USS (dT )2 + (UV V - )(dV )2
USS
"2U "2U
= (dT )2 + (dV )2 a"
2 2
"T "V
V T
UT T (dT )2 + UV V (dV )2.
"2U " "U "P 1
= = - = .
2
"V "V "V "V V T
T T T
dV
dT UT T
USS
"2U "T T
USS = = = .
"S2 V "S CV
V
CV 1
d2U = (dT )2 + (dV )2.
T V T
dT dV
CV e" 0, T e" 0,
"T "P
e" 0, d" 0.
"S "V
V T
L(q1, .., qn, q1, ..qn, t)
Ł Ł
H(q1, ..., qn, p1, ...pn, t)
n
H(q1, ..., qn, p1, ...pn, t) = L(q1, .., qn, q1, ..qn, t) - qipi
Ł Ł Ł
i=1
"L
pi = , (i = 1, 2, ..n)
"qi
Ł
U U(S, V, N1, ..., Nn)
F = F (T, V, Ni)
"U "F
F = F (T, V, Ni), T = , -S =
"S "T
F = U - T S, dF = -SdT - P dV + idNi
U = U(S, V, Ni) V P E
"U "E
E = E(S, P, Ni), -P = , V = ,
"V "P
E = U + P V, dE = T dS + V dP + idNi.
U S T V P G =
G(T, P, Ni)
"U "G
G = G(T, P, Ni), T = , -S =
"S "T
"U "G
-P = , V =
"V "P
G = U - T S + P V, dG = -SdT + V dP + idNi.
ś
S T N
"U "ś
ś = ś(T, V, ), T = , -S =
"S "T
"U "ś
i = , -N =
"N "
ś = U - T S - N, dś = -SdT - P dV - Nd.
M
H T V, P, T
V -M, P H.
P H
"M
 = ,
"H
dU = T dS + HdM, dE = T dS - MdH,
dF = -SdT + HdM, dG = -SdT - MdH.
"U "E "G "F
T = = , S = - = -
"S "S "T "T
M H H M
"U "F "E "G
H = = , M = - = -
"M "M "H "H
S T S T
U F, E G
"2F "2F
CV = -T , (T )-1 = V
2 2
"T "V
V T
"2F "2G "M
CH = -T , T = - = .
2
"T "H2 T "H
H T
(x1, ..xf ) f
1
S =
2
m OZ
1
m ą
2
OX
1
En = (n + ) 
2

n = 1, 2, .. N N n1, ..., nN
(q, p)
h = pq
h
h (pq e" )
r
1
S =
2
ąB B H
OZ
1
mi = ą , (i = 1, 2, 3)
2
1
m1, m2, m3 ei = BH mi = - ei = -BH
2
1
mi = E
2
M
m1 m2 m3
B -3HB
B B
B B
B B
-B B
-B B
-B B
-3B B
-BH
-BH (+ + -), (+ - +), (- + +)
-BH
(+ + -) (+ - +) (- + +)
(E, E + E)
&!(E)
-BH y
yk
&!(E, yk) +1
&!(-BH, -1) = 2 &!(E, yk)
y
yk
&!(E, yk)
P (yk) = .
&!(E)
y
yk&!(E, yk)
< y >= = P (yk)yk.
&!(E)
k
yk
-BH
(+ + -) (+ - +) (- - +) P+
OZ
2 1 1
< B > a" < y > = B Pk(yk)yk = B - B = B.
3 3 3
k=ą
A A
Ć
A = A + A
A (E, E +E) &!(E) A
(E , E + E ) &! (E )
Ę = E + E = const.
f
&!(E) <" Ef .
N
N
N
N(N - 1)/2
1/2 OZ
Ą Ą/2
Ć
&!(E) A
(E, E + E) E E
E
P (E)
A (E, E + E)
Ć
&!(Ę)
P (E) =
Ć
&!
Ć
&!
Ć
P (E) = C&!(Ę),
Ć
C E &!(E) A
(E, E + E) A A
Ć
&!(E) = &!(E)&! (E ) = &!(E)&! (Ę - E),
P (E) = C&!(E)&! (Ę - E).
&!(E) <" Ef E &! (Ę -E)
E &! (E ) E
ź
ln P P ln P
"P
= 0.
"E
ln P (E) = ln C + ln &!(E) + ln &! (Ę - E) =
= ln C + ln &!(E) + ln &! (E ).
" ln &!(E) " ln &! (E )
- = 0,
"E "E
"&! (E ) "&! (E) "E
= - .
"E "E "E
" ln &!(E)
a" (E).
"E
ln P
(E) =  (E ).
E E A A lnP (E) 
T
(kBT )-1 a" .
T kB kB =
1.38054 10-16erg/st
S = kB ln &!.
&!(E)
T = T
1 "S
= ,
T "E
E U
&!(E)
y
P (yk) P (y)
V N (E, E +E)
P (Er)
Er
C : E < Er < E + E
P (Er) =
0 :
C
P (Er) = 1.
r
Ć
A A
A A
A A A Er E Er
A A
Pr A r Er
Er + E = Ę = const.
Ć
A r A
A E = Ę - Er
Pr = C &! (Ę - Er).
C A A
Er E ln Pr E = Ę 0
" ln &! (E )
ln &! (Ę - Er) = ln &! (Ę) - Er + ...
"E 0
ln P P ln
ln P P
Er E
" ln &!
=  = (kBT )-1,
"E 0
Er
A A A
ln &! (Ę - Er) = ln &! (E ) - Er
&! (Ę - Er) = &! (E ) exp(-Er).
C &! (Ę) Er
Pr = C exp(-Er).
C
exp(-Er)
Pr = .
exp(-Er)
r
A
Er
Pr exp(-Er)
A
y
r
yre-E
< y >= .
r
e-E
H(p, q)
y
< y >= C ye-H(p,q)d
a" C y (p, q)d
d N
d = h-3N (2Ą)-3N dp1dp2, ..., dpN dq1dq2, ..., dqN .
h3N (p, q)d
(p, p+dp, r, rdr)
(q, p) = exp(-H(q, p))
T
V
A
p2
E = .
2m
(r, r + dr)
(p, p + dp) P (p, r)dp dr
(dp dr/h3)
exp(-E)
d3p d3r 2
P (p, r)d3p d3r = C e-p /2m.
h3
P r r
P (p)d3p (p, p + dp) r
2
P (p)d3p = P (p, r)d3pd3r = Ce-p /2md3p.
r
(v, v + dv)
2
P (v)d3v = Ce-mv /2d3v.
N S = 1/2

H
<  > i = ą
(+) H
= -H (-) = H
+ -
(+) (-)
+
P+ = Ce- = CeH, P- = Ce-H.
H
y = H = ,
kBT
H
T
iP (i) P+ - P-
<  > = = =
P (i) P+ + P-
eH - e-H
= th(H).
eH + e-H
H
T <  >, H, T
M = N <  >
kBT H y 1
<"
ey <" 1 + y, e-y <" 1 - y, ! th y y 1.
= = =
<  >H" y H" 0,
N2
M = H = H,
kBT
N2 C
 = <" .
kBT T
kBT BH ! y 1
ey e-y ! th y H" 1.
<  >= th (H) H" .
r
Z a" ZN (V, T ) a" e-E .
r
r
Pr = Z-1e-E .
r
Ere-E 1 "Z "lnZ
< E > = = - = - .
r
e-E Z " "
< ("E)2 > = < (E- < E >)2 > = < E2 > - < E >2 .
1 "2Z
2
r
< E2 > = Z-1 Er e-E = =
Z "2
r
2
" 1 "Z 1 "Z " < E >
= + = - + < E >2 .
" Z " Z2 " "
" < E > "2lnZ
< ("E)2 > = - = .
" "2
x
x d W
"Er "Er
r
dW = - < "xEr > = - < dx > = Z-1 - dx e-E .
"x "x
r
 x
"Er 1 "
r r
- e-E = e-E
"x  "x
"Z " ln Z
dW = Z-1-1 dx = -1 dx.
"x "x
ln Z
" ln Z " ln Z
d ln Z = d + dx = - < E > d + dW,
" "x
d(< E > ) = d < E > + < E > d
d ln Z = dW + d < E > -d(< E > )
d(ln Z +  < E >) = (dW + d < E >) = dQ
d Q
d Q
dS = .
T
-1 -1
d(ln Z +  < E >) = dQ = T dS = kB dS = d(kB S),
-1
ln Z +  < E >= kB S,
kBT ln Z+ < E >= T S kBT ln Z = T S- < E >= -F.
< E > U
F = -kBT ln Z.
F Z
F Z
A A
A
Ć
A = A + A
Pr A Er Nr
A r
Ć
Pr(Er, Nr) = C&! (Ę - Er, N - Nr).
A &!
Ć Ć
ln &! (Ę - Er, N - Nr) ln &! (Ę, N) -
" ln &! " ln &!
Er - Nr
"E 0 "N 0
A
" ln &!
a" .
"E 0
S = kB ln &!
" ln &! "S
= (kB)-1 .
"N 0 "N
0
dU p
dU = T dS - pdV + dN ! dS = + dV - dN
T T T
S = S(U, V, N)
"S "S "S
dS = dU + dV + dN,
"U "V "N
"S
= -T .
"N
r
Ć Ć
&! (Ę - Er, N - Nr) = &! (Ę, N)e-E +Nr,
r r r
Pr = Ce-E +Nr = Ce-E N ,
 = exp() C
" "
r r r
C-1 = e-E N = ZN N a" ZG(, V, T ).
r
Nr=0 r Nr=0
ZG(, V, T )
Er Nr
-1
r r
Pr = ZG e-E N ,
r r
N e-E Er " ln ZG
< E > = = - ,
r r
e-E N "
V,N
r r
N e-E Nr " ln ZG
< N > = = .
r r
e-E N "
T,V
ZG
ś
ś = -kBT ln ZG(, V, T )
Ń
Ń
f
(q, p) E = E(q1, ...qf , p1, ...pf )
pi
E = (pi) + E (q, p)
i
E pi
pi
i
(pi) = bp2
i
i
b
pi
p2 p
exp(-E) dp dq
i
< >= .
i
exp(-E)dp dq
exp (-( + E )) dp dq
i i
< >= =
i
exp (-( + E )) dp dq
i
exp(- ) exp(-E )dq dp exp(- )dpi
i i i i
= =
exp(- ) exp(-E )dq dp exp(- )dpi
i i
"
- exp(- )dpi " "
i
"
i
= = - ln e- dpi .
exp(- )dpi "
i
-"
" "
2
i
i
W a" e- dpi = e-bp dpi.
-" -"
y = 1//2pi
2 2
W = -1/2 e-by dy ! ln W = -1/2 ln  + ln e-by dy.
T 
" 1 1
< >= - - ln  =
i
" 2 2
1
< >= kBT.
i
2
kBT
N V
N
p2
i
E = + U(r1...rN ),
2m
i=1
ri, pi i U
1
Z = h-3N exp - (p2 + ... + p2) + U(r1...rN ) d3r1...d3rN d3p1...d3pn,
1 1
2m
2 2
1
1 N
Z = h-3N e-(/2m)p d3p1... e-(/2m)p d3pN e-(U(r ...rN )d3r1...d3rN .
"
2
e-(/2m)p d3p,
-"
U
N
"
V 2
Z = śN a" e-(/2m)p d3p .
h3 -"
"
2
ś = e-(/2m)p d3p =
-"
3/2
"
2 2mĄ
x y z
= e-(/2m)(p +p2 +p2)dpxdpydpz = .

-"
3 3 2Ąm
ln Z = N ln V - ln  + ln .
2 2 h2
" ln Z N
< p >= kBT = kBT ,
"V V
< p > V = NkBT.
" ln Z 3N 3 3
< E >= - = = 3N < e > = kBT N = < p > V,
" 2 2 2
3
< e >= kBT
2
" < E > 3
CV = = NkB.
"T 2
V
3 3 2Ąm 3
S = kB(ln Z +  < E >) = NkB ln V - ln  + ln + ,
2 2 h2 2
3
S = NkB ln V + ln T +  ,
2
3 2ĄmkB 3
 = ln +
2 h2 2
V
3
S = S = N kB(ln V + ln T + ),
2
3
S = 2N kB(ln 2V + ln T + ),
2
S - 2S = 2N kB(ln(2V ) - ln V ) = 2N kB ln 2.
N
Z
<"
Z = ! ln Z = ln Z - ln N! ln Z - N ln N + N.
=
N!
T V
< E >
S = kB(ln Z +  < E >) =
3
= kBN(ln V + ln T + ) + kB(-N ln N + N) =
2
V 3
= kBN(ln + ln T +  ),
N 2
 = 
N
T H
e = -mH,
m
-S, ... + S
S
Z = emH,
m=-S
 = m
S
<  >= Z-1 memH.
m=-S
S
1 "Z
memH = .
 "H
m=-S
1 1 "Z 1 " ln Z
<  >= = .
 Z "H  "H
H
kT
H
y = = H.
kT
S S -1
Z = eym = eym + eym =
m=-S m=0 m=-S
S S
1 - ey(S+1) e-y(1 - e-yS) e-y(S+1) - e-yS
= eym + e-ym = + = .
1 - ey 1 - e-y 1 - ey
m=0 m=1
e-yS - ey(S+1) e-y(S+1/2) - ey(S+1/2) sinh(y(S + 1/2))
Z = = = .
1 - ey e-y/2 - ey/2 sinh(y/2)
ln Z = ln sinh(S + 1/2)y - ln sinh y/2.
1 " ln Z "y " ln Z
<  >= = .
 "y "H "y
(2S + 1) cosh(2S + 1)y/2 cosh y/2
<  >= -
2 sinh(2S + 1)y/2 sinh y/2
<  >= SBS(y),
BS(y)
BS(y) = (2S)-1 [(2S + 1) coth(2S + 1)y/2 - coth y/2] .
S
N < M >
< M >= N <  >= NSBS(y).
y 1
1 y
coth y <" + .
y 3
1 2(2S + 1) (2S + 1)2y 2 y
BS(y) <" + - - =
2S (2S + 1)y 6 y 6
1 y (S + 1)y
= (2S + 1)2 - 1 = .
6 2S 3
y 0
y 1
s + 1 S + 1
< M >= H <" NS , y = NS H
3 3
2S(S + 1) C
 = N <" ,
3kBT T
S
y 1
coth y <" 1,
S + 1 1
BS(y) <" S-1 - = 1.
2 2
M <" SN.
N
x
xi xk
s(x1, , ..xi, ..xk, ..xN ) = s(x1, , ..xk, ..xi, ..xN ),
a(x1, , ..xi, ..xk, ..xN ) = -a(x1, , ..xk, ..xi, ..xN ).
xi = xk
a(...xk, ..xk, ..) = -a(...xk, ..xk, ..).
 = 0
F (q, p)
< F >= Z-1 F (q, p) (q, p)dq dp
(q, p) q p
t |k(t) >
Ć
L |Lk >
| >
|Lk >
|j(t) >= |Lk >< Lk|j(t) >a" aj(Lk; t)|Lk >,
k k
aj(Lk; t) a"< Lk|j(t) > .
P (k, t)
t |k >
Ć = |k(t) > P (k; t) < k(t)|.
k
Ć
Ć
L
< Lj| Ć|Li >= < Lj|k > P (k; t) < k|Li >=
k
= ak(Lj; t)a"(Li; t)P (k; t).
k
k
i = j
< Li| Ć|Li >= |ak(Li; t)|2P (k; t).
k
|ak(Li; t)|2 t
|k > |Li > P (k; t) |k >
< Lk| Ć|Lk >a" T r Ć = 1,
k
(q, p; t)d = 1.
Ć
F
|k >
P (k)
Ć Ć|k
< F >= < k|F > P (k).
k
|Li >
Ć Ć|k
< F >= < k|Li >< Li|F > P (k) =
k i
Ć|k
= < Li|F > P (k) < k|Li > .
i k
|k > P (k) < k| = Ć,
k
Ć Ć Ć|Li Ć Ć) Ć).
< F >= < Li|F >= T r(F = T r( ĆF
i
< F >= F (q, p) (q, p)dq dp.
Ej (E, E + E)
&!(Ej)
= i,jCj,
i,j
&!-1(Ej) : E < Ej < E + E
Cj =
0 :
|i >< i|.
Ć = &!-1(E)
E |i > Ei
-1
i
P (i) = ZN e-E .
-1 -1 -1
i
Ć = ZN e-E |i >< i| = ZN e-$|i >< i| = ZN e-$.
i i
i
ZN = e-E = T r e-$.
i
e-$
.
Ć =
T r e-$
T r xe-$ -1
Ć
< x >= T r (x) = = ZN T r xe-$.
Ć ĆĆ Ć
T r e-$
"
ZG(, T, V ) = N ZN (T, V ).
N=0
T
En = (n + 1/2),  = k0/m, (n = 1, 2, ...)
n
T r $e-$ n Ene-E "
< E >= = = - ln ZN .
n
e-E "
T r e-$
n
"
n
ZN = e-E = e- (n+1/2) =
n=0 n
n -1
= e-1/2  e-  = e-1/2  1 - e-  .
n
1
ln ZN = -   - ln 1 - e-  .
2
" ln ZN 1 e-  1 1
< E >= - =  + =  + .
" 2 1 - e-  2 e  - 1

1 ! e  1.
kBT
1
< E >= ( + e- ).
2
T 0
1
E0 = .
2

1   1.
kBT
e 
1 1
< E >=  + H"
2 (1 +   + ...) - 1
1 1 1
H" ( + ) H"  .
2    
( )-1 2
< E >= kBT.
p2 1
E = + k0x2.
2m 2
1 1
< Ek > = kBT, < Ep > = kBT.
2 2
< E > = kBT.
N V T
r s r r nr
r
R R
ER = n1 + n2 + ... = nr,
1 2 r
r
R r
r
ZN = e-E = e- nr.
R R
s
r
r
nse- nr
R
< ns >= ,
r
r
e- nr
R
r
r
nse- nr
n1n2,..
< ns >= =
r
r
e- nr
n1n2,..
s r
r
nse- ns (s) e- nr
ns n1n2,..
= .
s r
r
e- ns (s) e- nr
ns n1n2,..
(s)
s
(s)
s
nse- ns
ns
< ns >= =
s
e- ns
ns
1 "
s
= - ln e- ns .
 " s ns
" "
ns -1
s s s
e- ns = e- = 1 - e-
ns=0 ns=0
1 "
s
< ns >= ln 1 - e- .
 " s
-1
s
< ns >fot = e - 1 .
s
(s)
s
0 + e- ZN-1
1
< ns >= = .
(s) (s)
(s) (s)
s
s
ZN + e- ZN-1 ZN /ZN-1 e + 1
(s)
1 1 2
ZN a" e-(n +n2 ..)
n1,n2,..
(s)
s N ZN-1 s
(s)
s ZN s
"N "N = 1
"N ln ZN-"N
" ln Z(s)
(s) (s) (s)
ln ZN-"N ln ZN - "N = ln ZN - ąs"N,
"N
(s) (s)
s
ZN-"N = ZN e-ą "N
" ln Z(s)
ąs a" ,
"N
s Z(s)
ą
" ln Z
ąs = ą ! ą = .
"N
Z
"N
(s)
ZN
= e-ą,
(s)
ZN-1
s
-1
s
< ns >F D = e +ą + 1 .
s
ą N
-1
r
e +ą + 1 = N.
r
" ln ZN "F
F = -kBT ln ZN ! ą = = - = -.
"N "N
ą = -
-1
s-)
< ns >F D = e( + 1 .
(s)
nr = N ZN-"N
r
ą
(s) (s)
s s
0 + e- ZN-1 + 2e-2 ZN-2 + ...
< ns > = =
(s) (s) (s)
s s
ZN + e- ZN-1 + e-2 ZN-2 + ...
(s)
s s
ZN 0 + e- e-ą + 2e-2 e-2ą + ...
= .
(s)
s s
ZN [1 + e- e-ą + e-2 e-2ą + ...]
s s
nse-n (ą+ )
s
< ns > = .
s s
e-n (ą+ )
s
  + ą
s s
-1
s
< ns >BE = eą+ - 1 .
ą
-1
s-)
< ns >BE = e( - 1 .
< ns > N
ą
r r
nsen (- )
r
< ns >BE = .
r r
en (- )
r
exp() < 1
s
< 0
N T V
"F
= 0
"N
"F
= ,
"N
V,T
= 0

(n1, n2, ...) N!//(n1!n2!...)
N n1 1 n2 2
nr = N
r
MB
ZN = N!(n1!n2!..)-1 exp - nr =
r
n1,n2,.. r
N! n1 2 n2
1
= e- e- ...
n1!n2!...
n1,n2,..
nr = N N
r
N
MB
1 2
ZN = e- + e- + ... .
MB
r
ln ZN = N ln e- .
r
s
" ln ZN e-
< ns >MB= -kBT = N .
r
" s e-
r
ZN = exp(-  nr).
r
R r
-1 -1
n1 2 n2
1 1 2
ZN = e- e- ... = 1 - e(- ) 1 - e(- ) ...
n1,n2,..
f
r
ln ZNot = - ln 1 - e- .
r
N N N
N ZN N H" N
N = N
exp(-ąN )
N = N
ZN e-ąN ZN e-ąN "N .
N
"N
"N N ZG
ZG = ZN e-ąN ! ln ZG = ln ZN - ąN + ln "N .
N
ln "N
ln ZN = ąN + ln ZG.
ZG
ZG = exp - nr exp -ą nr =
r
R r r
"
n1 " n2
1 2
= e-( +ą) e-( +ą) ... =
n1=0 n2=0
-1 -1
1 2
= 1 - e-(ą+ ) 1 - e-(ą+ ) ...
r
R
, , ..
1 2
r r
ln ZG = - ln 1 - e-ą- ! ln ZN = ąN - ln 1 - e-ą- .
r r
ą = -
BE
r
ln ZN = -N - ln 1 - e(- ) .
r
1 1
ZG = exp (-(ą +  )n1) exp (-(ą +  )n2) ... =
1 2
n1=0 n2=0
1 2
= 1 + e-ą- 1 + e-ą- ...
r
ln ZG = ln 1 + e-ą- .
r
F
r
ln ZND = -N + ln 1 + e(- ) .
r
V
T
-1
s
< ns > = e - 1 .
= , p = k,
 k k = /c c
V
Lx, Ly, Lz
2Ą
kx = nx,
Lx
nx ky kz
nx kx (kx, kx + dkx)
Lx
"nx = dkx,
2Ą
( k, k + d k)
( k) d3k = "nx"ny"nz =
LxLyLz V
= d3k = d3k.
(2Ą)3 (2Ą)3
Nk = f( k)d3k
( k, k + d k)
V d3k
Nk = f( k)d3k = n( k) ( k)d3k = .
(2Ą)3 e - 1
n( k) k f( k)
k
4Ą k2 dk 1
Nkdk = f(k)(4Ą k2 dk) = V =
(2Ą)3 e  - 1
4Ą V 2 d
= = Nd.
(2Ąc)3 e  - 1
k = /c
(,  + d) 
8Ą
< e(, T ) > d = 2N d = f(k)3 d,
c3
3 d
< e(, T ) > d = .
Ą2c3 e  - 1
 T
kBT
< e(, T ) > d = 2 d,
Ą2c3
e  1
< e(, T ) > d = 3e- d.
Ą2c3


 = .
kBT
4
kBT 3 d
< e(, T ) > d = .
Ą2c3 e - 1
 max H" 2, 822
T1 1 T2 2
1 2 1 2
= = max ! = .
kBT1 kBT2 T1 T2
4
" "
kBT 3 d Ą2
< e(T ) >= < e(T, ) > d = = (kBT )4,
Ą2c3 e - 1 15(c )3
0 0
"
x3 dx Ą4
= .
ex - 1 15
0
4
Ą2kB
 =
3
60 c2
4 4
4 4
< e(T ) > = T ! < E(T ) > = V T .
c c
" < E > 16
3
CV = = V T .
"T c
V
-1
s-)
< ns >= e( + 1 .
F ( ) =< ns >
T = 0 > < n >= 0. < < n >= 1.

= T > 0
F
F ( ) 1 0 2kBT
1.4
1.2
1
0.8 T = 0
< n >
0.6 T > 0
0.4
0.2
F
0
T = 0
pF = kF ,
2mF
2
kF = .
2
ep = p2/2m
p
ln ZG = ąN - ln 1 - śe-e .
p
ś = e
r
" śe-e
N = ś ln ZG = .
r
"ś 1 - śe-e
r
"
2ĄV
pdp.
h2 0
r
2
"
" "
2ĄV śe-p /2m 2ĄV 2 2
N = p = śe-p /2m śne-p n/2mpdp =
2
h2 0 1 - śe-p /2m h2 0
n=0
"
"
2ĄV 2
= śn e-p n/2mpdp.
h2
0
n=0
p2 
= x ! pdp = dx
2m m
" "
"
2ĄV m 2ĄV m 1
"
N = śn e-nxdx = śn - e-kx 0 =
h2  h2  n
0
n=0 n=0
"
2ĄV śn V mkBT
= mkBT = ln(1 - ś).
h2 n 2Ą 2
n=1
2
2Ą N
- ln(1 - ś) =
V mkBT
ś
2
2Ą N
ś = 1 - exp - .
mkBT V
pV
P
= ln ZG = - ln 1 - śe-e .
kBT
p
"
p2
pV 2ĄV
2m
= p ln 1 - śe- dp =
kBT h2 0
" "
"
p2 p2
2ĄV śn 2ĄV śn "
2m 2m
= p e- dp = pe- dp =
h2 0 n=1 n h2 n
0
n=1
"
2ĄV śn
= mkBT .
h2 n
n=1
ś
" n
2
pV mkBT V 1 2Ą N
= 1 - exp - .
2
kBT 2Ą n2 mkBT V
n=1
t "
2 2 2
2Ą N 2Ą N 2Ą N 1
1 - exp - <" 1 - 1 - <" -
mkBT V mkBT V mV kBT
2
pV mkBT V 2Ą N 1
H" <" N.
2
kBT 2Ą mV kBT
pV = NkBT.
T 0
2
2Ą N
exp - <" 0,
mkBT V
"
m 1 mĄ
p <" (kBT )2 = (kBT )2.
2Ą 2 n2 12 2
n=1
E(x1, x2) = E1(x1) + E2(x2) + Eodd(x1, x2).
N
mi
xą i ą
Ći
ą
xą i
i
ą
i = xą - xą.
Ći
i
N 3 N 3
2
1 1
ą
Ek = mi (ą)2 = mi Łi ,
i
2 2
i=1 ą=1 i=1 ą=1
xi 
Ć
V (x1, x2, ..., xN )
"V 1 "2V
ą ą 
V = V0 + i + i j + ...
"xą (0) 2
"xą"x
i
i j
i ą i,j ą,
(0)
V0 V V
1
ą ł
V = V0 + Aąłi j ,
ij
2
i,j ą,ł
1 1
ą ą ł
H = V0 + mi(Łi )2 + Aąłi j .
ij
2 2
i,ą i,j ą,ł
A
3N
ą ą
i = Bi,rqr.
r=1
3N
1
H = V0 + qr + r qr .
Ł2 2 2
2
r=1
qr
qr qr
Ł
3N
r qr
nr = 0, 1, 2..
= r (nr + 1/2) 3N
r
3N 3N
1
E = V0 + nr + r = -N + nr r,
2
r=1 r=1
3N
1
-N = V0 + r
2
r=1
 T = 0
3N
ZN = exp - -N + ni i =
n1n2,.. 1
" "
= eN e- 1n1 ... e- 3N n3N =
n1=0 n3N =0
-1 -1
= eN 1 - e- 1 ... 1 - e- 3N .
3N
ln ZN = N - ln 1 - e- r .
r=1
N r
()d
(,  + d)
"
ln ZN = N - ln 1 - e-  ()d.
0
"
" ln ZN 
< E > = - = -N + ()d,
" e  - 1
0
" < E > " < E >
CV = = -kB2 =
"T "
V V
"
e 
= kB ( )2 ()d.
0 (e  - 1)2
()
() max
() = 0  > max
 max 1  max
e  = 1 +   + ...
kBT max
"
CV = kB ()d = 3NkB,
0
()d
3N
CV = 3NkB
S = 1/2
OZ
OZ
N
H = -J ii+1,
i=1
J
z a"  i i+1
i = ą1.
N
N N
N-1
ZN = T re-H = T r exp K ii+1 =
i=1
N-1
= ... exp K ii+1 =
1=ą1 N =ą1 i=1
N-2
N-1
= ... exp K ii+1 eK N .
1=ą1 N-1
=ą1 i=1 N =ą1
K = J
N-1 N-1 N-1
eK N = eK + e-K = 2ch K
N =ą1
N-1
ZN = (2ch K)) ZN-1 = (2ch K))2 ZN-2 = ... = (2ch K))N-2 Z2.
Z2
1 1 1
Z2 = eK 2 = eK + e-K = 4 ch K.
1=ą1 2=ą1 1=ą1
N-1
J
ZN = 2(2ch K)N-1 = 2 2ch .
kBT
" ln ZN
< E >= - = -Jth K,
"T
" < E > kBK2
CV = -T = .
"T ch2K
V
3
ą ą ą
HHeis = - JijSi Sj
i,j ą=1
2
ą ą ą
HXY = - JijSi Sj .
ij ą=1
z
ą
z 
H
Sz
OZ
z
HHeis = - JijSi Sj - H Si .
i,j i

H
z
H = H0 - H Si ,
i
H0
ł ł
z -1 z
ł
M(T, H) = < Sj >= ZN T r Sj e-Hłł ,
j j
ł ł ł ł łł
"M(T, H) "ZN -1 ł z "
-2 z
łZN ł
T = = = T r Sj e-Hłł + ZN T r Sj e-Hłłłł .
"H "H "H
j j
N
"H
z
= - Sk,
"H
k=1
N
"
z
e-H =  Ske-H,
"H
k
N
"ZN
z
= T r Si e-H .
"H
i
T =
N N
-1 z -1 z
= 2 -ZN T r Ske-H ZN T r Si e-H +
k i
N N
-1 z z
+ZN T r Sk Si e-H =
k i
N
-1 z z -1 z z
= 2 ZN T r SkSi e-H - ZN T r Ske-H Si e-H =
i=1 k k
N N N
z z z
= 2 < SkSi > - < Sk >2 .
i=1 k=1 k=1
N N
z z
T = 2 < SkSi > -BM2(T, H).
i=1 k=1
i k
z z z z z
< SkSi > = < Sk >< Si > = < Sk >2 .
P V
T
(P, V, T )
(P, T )
I II III x a
b c
a
(Tc, Pc) c
III
II c
(P, V )
pc
Tc
(P, T )
T = Tc
T < Tc
I II III
c - g
Tc
Tc
Tc
T = 0
(P, V ) (M, H) Tc
Tc
"P "2P
= 0, = 0.
2
"V "V
T T
T < Tc
F = -kBT ln Z(T, V, N),
Z(T, V, N)
d3N pd3N q
Z(T, V, N) = e-H(p,q)d, d = ,
N!h3N
Z(T, V, N) = T re-H.
V Z(T, V, N)
 F
V
N ", V "
 = N/V
&! V
ZN () = eNK()ch (N ( - ")) ,
 , " ZN ()
iĄ
r = " ą (2r + 1) , (r = 0, 1, 2...)
N
  "
N < " N "
ln ZN
N-1 ln ZN () = K() + N-1 ln ch (N ( - ")) ,
"
u() = - N-1 ln ZN () = -K () - th (N ( - ")) .
"
N u() 
N "
U
N < "

N "  = "
lim u() = -K () - ,  > ",
N"
lim u() = -K () + ,  < ",
N"
 = " 2
N 1023
N
s ą1/2
ą ą 
ą  ł
H = G0 + Gą(j)Sj + Gą(j, k)Sj Sk + Gął(j, k, l)Sj Sk Sl + ...
ą, , ł = x, y, z G
S
G
ą  ł

H = G0 + G(j, k)SjSk + O(Sj Sk Sl Sm)
J(j, k) = -G(j.k) - G(k, j).
1
H = G0 - J(j.k)SjSk.
2
J(j, k) = J(|j - k|).
H
1
H = G0 - J(j, k)SjSk + HSj.
2
Hef
Hef = łM
ł
HMF A = Hi,
Hi = (H + Hef ).
E = ą1/2H
H H H
Z = exp( ) + exp(- ) = 2 cosh( ).
2 2 2
M = N < Sz >
m = M/N
MF A
T rSze-H 1 łH 1 m
m =< Sz > = = tanh( ) = tanh( ).
MF A
T re-H 2 2 2 2
1
0.8
0.6
m
0.4
0.2
0
0 0.25 0.5 0.75 1 1.25 1.5
temperatura


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