Inertial and dissipative properties of chaotic system

Inertial and dissipative properties of chaotic system

Nuclear Physics A545 (1992) 561c-56~Sc North-Holland, Amsterdam NUCLEAR PH YSICS A INERTIAL AND DISSIPATIVE PROPERTIES OF CHAOTIC SYSTEM V . M . Kol...

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Nuclear Physics A545 (1992) 561c-56~Sc North-Holland, Amsterdam

NUCLEAR PH YSICS A

INERTIAL AND DISSIPATIVE PROPERTIES OF CHAOTIC SYSTEM V . M . Kolomietz and V. N . Kondratyev Institute for Nuclear Research of Ukraine, Kiev

Abstract Stochastic

approximation

approach is

developed

based

on

for

the

semiclassical

the

description

one-body

relaxation

of

finite

Fermi-system dynamics . The considerable exceeding of the smooth term of the cranking-model inertial coefficient under the hydrodynamic value is demonstrated . Connection between the friction

coefficient

and

established

time

is

i . INTRODUCTION The equations

interacting

of

motion

particles .

investigation of these

work we utilize such

However

are

the

not

intégrable

stochastic

methods

systems can be developed ti,2J .

approach

for

t~~e

calculations

inertial mass parameter B and friction coefficient 1~. framework of cran>
gcr - 2 ~ dE2 Here ~d ( g) and

s-.o

~~( g)

response functions :

for

many of

In this

of

In

the

the

dx (~) ~ . ~ -SLdE ~ ~-.o are

the

dissipat ve

and

polarization

0375-9474/92/$05 .00 © 1992 - Elscvicr Scicncc Publishers B .V. All rights rcservcd .

SC~`~~ t~.~i. r~to~~aicatz, V.dV. o®adraryev l A~tertial and dissipa~rive properties of a chaotic .system

P

d~, d ( ~° ) ?L

' g -E

a

and are where n~ are the occupat ion numbers, (p01, A g~. single-particle wave functions and eigenvalues, A is the one-body operator of cranking field . Usually the sum in eq .(2) is localized close to the Ferrai surface . In this case

In a semiclassical approximation the smooth term dissipative response function C4) of chaotic system written as t1,2] (2

of the can be

)

where C(g~,,t) is the classical correlation function C(~~,t)=

dp dr ~(g~, - h(~i,r))A(p,r)A(pt~rt)

(ë~)

Here (~~, r t ) is a paint of the phase space at time t, belongs to the classical trajectory with Hamiltonian and initial point The c .l.assical value (P, r) A. corresponds to the operator A .

which h(p,r) A(p, r)

CfI®

I?~F~2TIA1_

S

Let us consider a spherical poten~,ial ~( r) = tfo A( -r ; with a

o

(7)

small quadrupole deformation of the potential surface

V.M. Kolomietz, V.N. Kondratyev / Inertial and dissipative properties of a chaotic system 563c R(t) = R The

1 + ß(t)Y

a

following

m

(g)

perturbation

motion [4l

A= ~5/ 16~

(~ ) r

2o

P2-

operator

A

corresponds to this

7pa

The correlation function eq .(6) can be now written as C(~,t)

1

=

The index at t=d .

a P dp dr ~(E- 2m~p2`12a(~~)P2(t)`l2~(~P(t))Q(RG-r) af

r

means the initial point

r

of classical

Integrating in eq .(1d) over the space solid

(10)

trajectory

and momentum p we get

angle

s PF Ro C ( g~, t ) = m f drrz f d~~~ PZ ( cos P, Pt 0

where pue=

2mgF and (p, pt ) is the angle between r,m ""-~ mermen tcsm a_~,dl ~a,r . . t Lii .,e ~ .~ P t at i, me t .

the

initial

(i) Specular reflection

The trajectory turns

arcsin ~RG sin~ipl~ at each

through

surface

the

angle

reflection

7G-2ßf ~Qf point for

= the

specular reflection conditions . Therefore we have (P,Pt)

t+e - ti~2 ti ,2 (~-2Q f ) f t+d+~ (7L-2Bf)

L

ti

for +.,<0

(12)

far t>a

where , [ aJ i s the in+.,egAr part of a,

ti =

2R ~

cosQ f/vF

rcosQp/v~, , v~. = P~./m .

Using egs .(5), (11) ând (12) we obtain s ~0 7G P F 3~ (~~cos8f ) cos ( ~~cosPP) ~d ( g) = f dr rz ~d®~sinQp s in m$~ ( 27C`~) ` 0 0 x ~ n

Ô(?~cosQf+2Q f +n7G) +Ô(2~cos(3 f-2Qf-n7L)

r

( 13)

St~4~ V

olomietz, V.N. ondratyev l inertial and dissipative properties ofa chaotic system

From

.(

the polarization response function is

) and (1~)

s ~ 7G p ~ 127L r 2 d8psin$~,sin(2$f) dr ,~t E) _(2 ) m o (-i) n ( 2 8t+n 7L) a

x ~dere

a =

~' = gsg~, E

rcos$

cos

(14 )

ß ( 2 yf+n7G) ~

i1~./R Q . In the adiabat ic 1 imit

( v«i )

we

have ~,~( E)

(O) +27Cv~

_

2 5°i pF` ï0 (2

R3 o

~'a + . . .

)

(15 )

Using this expression we find the smooth part

of the cranking

mass eq . ( i ) as BC ~,

_

(25?d70)

2

(87C

(16)

AmRô) .a 5, 5H h

where A is the number of particles and Hh is ~..he usual inertial coefficient for irrota~ional liquid drop [5) . The much

value

of

the

cranking

hydrodinamical one

can

be

mass

in

explained

comparison as

the

greater

with

vortex

the

motion

contribution to HcP . (ii) Isotropic reflection Let us assume that

the

reflections

toward

the

sphere

interior angle-independent . This reflection property should be taken into account in eq .(11) as the additional averaging aver

a scattering angle d~~ at the arbitrary reflection point k : C(E,t)

s Ro p~ . di~~ dr r 2 d~ jl ~ ~~ = m

47C 5

0

where the prime near

an

integral

Y2~(~1p) Ya (~p (t) ) %1 over

~k

means

(17)

that

the

integration is fulfiled over the internal region of the sphere,

The corresponding response functions are given by ~(E)

E~ 2

sinzv_

sin(2~)

V.M. Kvlomietz, V.N. Kondratyev l Inertial and dissipative properties ofa chaotic system

x,it( B)

kFR° 3 SF

=27G ~

27L

~v

a

sin2?~ - cos ( 2v) 2v

565c

(sg)

Now the smooth cranking mass is B~r = (3/1a7L)

(AmR~) _ (4/5)B~,

(2d)

Thus, the vortex contribution vanishes due to the isotropic reflection conditions, and the average cranking mass is close to the irrotational fluid mass B h.

3 .ONB-SODY RELAXATION The behaviour of the time-dependent response function xd( t) = plays

2~ the

Im dW e l ~t

xd (i~)

_m important

collective motion .

role

_

(2 in

~

) a

d

4

dt

G(E F , t)

theory

of

(21) the

adiabatic

It determines the relaxation time tir and the memory effects by the collective motion . Using egs .(11), (12) and (Z7) we obtain ?G

k F.R a 3 E~BR f ( T) ~ 2 2~

sign { T) ,

where the function f(T) in the considered (i) Specular re±~lection f(T) S 8

( 22 ) above cases is :

_ (1-3{T/2) ~+2(T/2) s ) Q(2-~T~ ) cos(2(2k+3)~) 2{2k+3)

cos(2(2k-s)d~) 2 ( 2k-1)

(23) cos(2C2k+1)~) ~=~k+s , 2k+1 ~~k

where = 8(2k-!T~ ) arc cas (T/2k) g T=~~t/ . (ii)

Isotropic reflection

olo tet`® f.1V. vndratyev i loae~rt~al aaad dissipatsve pro~erties of a ci:antic systerr~ '(T) = ( -t

(24)

Th se

e tassions give the estimate of the relaxation time ®Av e for both cases . Finally, we can evaluate . tom eqs . C i) and (i~) the Z'riction coefficient k

(25)

This expression coincides with the well-known adiabatic s'riction coe~'ficient .for the one-body dissipation [6] . However, the relat ;nn between ~~ and ti t differs from the one in the kinetic theory .

Z

4 5 6

Feingold and A .Peres, Phys .Rev . A34 (i9~6) 59?2 ilkinson, J . Plays . A20 (i9~?) 2415 V. olo iet? and P .Siemens, Nucl .Phys .A314 (19i7) i :i2 A. igdal and V .P .1(rainov, The approximation methods of quant machete i cs : auka, Moscow, 1966 ohr and B . ottelson . Nuclear structure : Plenum, Mew York, 1965 S . . ~oonin, R . L . Hatch and J . Randrup, Nucl . Plays . A2B~ (19?7) 7