New variables for the Lema^{i}tre-Tolman-Bondi dust solutions

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r -q c /0105081v 1 23 M a y 2001

New variables for the Lema ??tre-Tolman-Bondi dust solutions.

Roberto A.Sussman ?and Luis Garc′?a Trujillo ?

?

Instituto de Ciencias Nucleares,Apartado Postal 70543,UNAM,M′e xico DF,04510,M′e xico.

?

Instituto de F′?sica,Universidad de Guanajuato,Leon,Guanajuato,M′e xico.

We re-examine the Lem?a itre-Tolman-Bondi (LTB)solutions with a dust source admitting symme-try centers.We consider as free parameters of the solutions the initial value functions:Y i ,ρi ,(3)R i ,

obtained by restricting the curvature radius,Y ≡

√

g θθ,containing two arbitrary functions of the radial coordinate:M (r )and E (r ).The integration of the

dynamical equation yields a third arbitrary function,t bb (r ).The ?rst two of these functions (M and E )are usualy identi?ed as the relativistic analogues of the newtonian mass and the local energy associated with the comoving dust shells,the third function (t bb )can be interpreted as the “bang time”,marking the proper time for the initial (or ?nal)singularity for each comoving oberver.The functions M,E,t bb are then the free parameters of the solutions,though any one of them can always be used to ?x the radial coordinate,thus there are realy only two free functions.Regularity conditions,related to well behaved symmetry centers,abscence of shell crossing singularities and surface layers,can be given as restrictions on these functions and their radial gradients.These functions are usualy selected by means of convenient ansatzes based on the interpretations described above and/or the compatibility with regularity conditions or observational criteria.Once the free parameters have been selected we have a completely determined LTB model.

Since the standard free functions lead to a consistent description of LTB models,these free functions are used in most literature dealing with these solutions (see [22]for a comprehensive and autoritative review of this literature).There are papers considering speci?c modi?cations of the standard free functions in order to formulate initial conditions for studying the censorship of singularities [20],or aiming at an “intial value”formulation of LTB models [9].We believe that new variables,de?ned along an arbitrary and regular “initial”hypersurface t =t i ,lead to a more intuitive understanding of LTB solutions.Therefore,we propose in this paper using a new set of basic free functions along the following steps

?Consider the rest mass density,ρ,the 3-dimensional Ricci scalar,(3)R ,and the curvature radius,Y ,all of them evaluated along an arbitrary Cauchy hypersurface,T i ,marked by constant cosmic time t =t i .This leads to:ρi (r ),(3)R i (r )and Y i (r ),where the subindex i indicates evaluation along at t =t i (we shall use this convention henceforth).

?Rescale Y with Y i ,leading to an adimensional scale factor y =Y/Y i ,so that we can distinguish between the regular vanishing of Y (at a symmetry center,now given as Y i =0)and a central singularity (now characterized as y =0).Likewise,we can distinguish between the two di?erent situations when Y ′=0:regular vanishing or surface layers if Y ′i =0for a single value of r (thus restricting gradients of ρi and (3)R i )and shell crossings when Γ=(Y ′/Y )/(Y ′i /Y i )=0.

?Among the three free functions,ρi (r ),(3)R i (r )and Y i (r ),we ?x the radial coordinate (as well as the topology of T i )by a convenient selection of Y i ,using the remaining two functions as initial value functions.

?From the latter functions we can construct suitable volume averages and contrast functions,all of which ex-pressible in terms of invariant scalars de?ned in T i .These auxiliary functions provide a clear cut and precise characterization of the nature of the initial inhomogeneity around a symmetry center,as overdensities (“lumps”)or underdensities (“voids”)of ρi and (3)R i .

The old functions M,E,t bb and their gradients can always be recovered and expressed in terms of the above mentioned volume averages and contrast functions.Hence,all known regularity conditions given in the old variables can easily be recast in terms of the new ones.In particular,the known conditions for avoiding shell crossing singularities [15](see also [16]and [17])have a more appealing and elegant form with the new variables,since with the old variables the signs of the gradients M ′,E ′,t ′bb

do not distinguish manifestly between lumps or voids.In terms of the new variables,it is evident that,in general,shell crossings are avoided only for lumps of ρi and (3)R i .However,some particular cases of initial conditions,such as a “simmultaneous bang time”(t ′bb

=0),do allow for some initial conditions given as voids to evolve without shell crossings.If we consider an evolution in the time range t >t i ,then (under speci?c restrictions)initial voids can also evolve without shell crossings.All these features could also emerge with the old free functions,but the new variables provide a more straightforward and intuitive characterization of the e?ect of initial conditions in the regular evolution of LTB models.

The new approach to LTB dust solutions presented in this paper accounts,not only for an initial value treatment on a regular Cauchy hypersurface T i ,but to a new formalism based on rescaling the evolution of the models to variables de?ned in this hypersurface.Some aspects of this formalism (average and contrast functions)have been developed elsewhere (see [26]and [28]for applications of LTB metrics with viscous ?uid sources).Variables similar to the ones introduced here have been de?ned in [2],[20],[9],[23]and [10](the latter in connection with Szekeres dust solutions,see equations 2.4.8to 2.4.14of [22]).Mena and Tavakol [11]have claimed that some of these variables are not covariant,thus suggesting covariant expressions for density contrasts (see also [24]).Although we show that the new variables can be expressed in terms of invariant scalars,and so are coordinate independent and can be computed for any coordinate system,we do not claim that the density and curvature averages and contrast functions introduced here have a clear “covariant interpretation”,or that they are unique.However,what we can certainly claim is that these new variables emerge naturaly from the ?eld equations,provide an adequate initial value treatment and yield a clear and concise description of regularity conditions.

The paper is organized as follows:section II reviews the basic expressions (metric,evolution equation and its solutions)characteristic of LTB models in the usual variables.The new variables are introduced in section III,leading to new forms for the metric,the rest mass density and the solutions of the evolution equation.Volume averages and contrast functions along T i are de?ned in section IV.Section V examines in detail generic properties of the new variables:regularity,symmetry centers and geometric features of the hypersurface T i (subsection V A),characterization of singularities (subsection V B),choice of radial coordinate and homeomorphic class (topology)of T i (subsection V C),expressing the new variables in terms of invariant scalars (subsection V D),FLRW and Schwarzschild (subsection limits V E).In section VI we look at the characterization of the inhomogneity of T i in terms density and 3-curvature “lumps”and “voids”and its relation with the contrast and average functions.In section VII we use the new variables in order to look at the conditions to avoid shell crossings,big bang times,regularity of the selected hypersurface T i and simmultaneous big bang times.A summary of the no-shell-crossing conditions is given in Table 1.Section VIII provides simple functional ansatzes for the new variables and their auxiliary quantities (volume averages,contrast functions,as well as the old variables and the big bang times).A simple step-by-step guideline is provided for the construction of LTB models and for plotting all relevant quantities derived from these ansatzes.The characterization of intial conditions as “lumps”and “voids”,as well as the ful?lment of the no-shell-crossing conditions is illustrated and tested graphicaly in 12?gures that complement the information provided in the text.Finaly,the Appendix provides a useful summary (in terms of the usual variables)of the generic geometric features of the solutions (regularity conditions,singularities,symmetry centers,surface layers).

Some important topics have been left out in this paper:time evolution of lumps and voids by generalizing volume averages and contrast functions to arbitrary times (t =t i ),models without centers,models with a mixed dynamics (elliptic and hyperbolic,etc),matchings of various LTB models,etc.The examination of these topics with the formalism presented here is currently in progress [29].

II.LTB SOLUTIONS,THE USUAL APPROACH.

Lemaitre-Tolman-Bondi (LTB)solutions are characterized by the line element

ds

2

=?c 2dt

2

+

Y ′2

Y

+E,(3)

4πG

Y 2Y ′

,(4)

where

M ≡

4πG

2

√

Y (2M ?|E |Y )

|E |3/2

arccos

1?

|E |Y

|E |3/2

,

c t (Y,r )=c t bb +

|E |

+

M

M

,˙Y <0,πM

|E |3/2

,

(7)

M

Y(η,r)=

|E|3/2[η?sinη],(9)?Hyperbolic solution,E>0:

±c(t?t bb)= E?M M ,(10)

M

Y(η,r)=

[sinhη?η],(12)

E3/2

where the signs±in the parabolic and hyperbolic cases distinguish between“expanding”or“collapsing”dust layers, that is Y increasing(+)or decreasing(?)as t increases,so that for any given layer r=const.,we have t>t

bb (collapse).Notice that the sign±is not necessary in the elliptic case,since dust layers bounce (expansion)and t

bb

(ie˙Y=0)as Y=2M/|E|and so both expansion and collapse are described by the same equations(8)and(9)and by each branch in the canonical solution(7).

As we mentioned before,t

(r)marks the proper time associated with Y=0for each comoving layer(ie the“bang bb

time”).The conventional interpretation for the other two free functions M and E is based on the analogue between

the dynamical equation(3)and an energy equation in newtonian hydrodynamics(see[1]),in which M and E are usualy understood,respectively,as the“efective gravitational mass”and the“local energy per unit mass”associated

with a given comoving layer.An alternative interpretation for E has been suggested as the local“embedding”angle of hypersurfaces of constant t([12],[13],[11]).The speci?cation or prescription of M and E is often made in the

literature by selecting“convenient”mathematical ansatzes that are somehow intuitively based on these interpretations, loosely based on newtonian anlogues.However,con?gurations without centers[13]have no newtonian analogue and

so the interpretation of M and E in this case is still an open question.Also,there is no newtonian equivalent for t

bb and no simple and intuitive way in which this function should be prescribed,though the gradient of this function has

been shown to relate to growing/decreasing modes of dust perturbations in a FLRW background[10][27][14][22],

can be suggested from this feature.

and thus the functional form of t

bb

III.NEW V ARIABLES

in terms of an alternative A useful formulation of LTB solutions follows by rede?ning the free parameters M,E,t

bb

set of new variables de?ned at a given arbitrary and fuly regular Cauchy hypersurface,T i,marked by t=t i(all such

hypersurfaces are Cauchy hypersurfaces in LTB solutions[7]).In order to relate the free function E to the scalar 3-curvature of T i,we remark from(A3)that the Ricci scalar of these hypersurfaces is given by

(3)R=?2(E Y)′

4πG

c 4

ρ(t i ,r )=

M ′

Y 2i Y ′

i ,(17)

as initial value functions de?ned in T i .The subindex i will indicate henceforth evaluation along t =t i .For the moment we

will

assume

this

hypersurface to

be

fuly regular,

we

discuss

the

corresponding

regularity

conditions

in

sections V A and VII.

In order to recast (3)and its solutions in terms of the new variables it is convenient to scale Y with respect to Y i .By de?ning the adimensional scale variable

y ≡

Y

1?

κY 2

i dr 2

+Y 2i

d θ2+sin 2θdφ2 ,

(19)

˙y 2=

2μ

Y 2Y ′

=

ρi

Y ′i /Y i

=1+

y ′/y

Y 3

i ,(23)

κ≡

K

2

κ

+

μ

μ

?arccos

1?

κ

κ3/2

(26)t (y,r )=c t i +

[2μ?κ]1/2+[y (2μ?κy )]1/2

κ3/2 arccos

1?

κy

μ

?2π

,

˙y <0,

πμ

κ3/2

,(27)

y (η,r )=

μ

κ3/2

[(η?sin η)?(ηi ?sin ηi )],

(29)

η=arccos

1?

κy

μ

,

(30)

?Hyperbolic solution c t (y,r )=c t i ±

[y (2μ+|κ|y )]

1/2

?[2μ+|κ|]

1/2

|κ|3/2

arccosh

1+

|κ|y

μ

,

(31)

y (η,r )=

μ

|κ|3/2

[(sinh η?η)?(sinh ηi ?ηi )],

(33)

η=arccosh

1+

|κ|y

μ

,

(34)

where,as before,the signs ±distinguish between expanding layers (?sign,t bb in the past of t i )and collapsing ones (+sign,t bb in the future of t i ).Explicit forms for t bb in terms of μ,κ,ηi and t i are given in section VII.

It is important to remark that y (t i ,r )=y i =1,by de?nition,and so y =1corresponds to t =t i .This is clear for the parabolic (25)and hyperbolic solutions (31)and (33).However,it is important to notice that c t i <πμ/κ3/2in (26)and so the initial hypersurface must be de?ned in the expanding phase in the elliptic solution.In this solution the correspondence between t =t i and y =1only holds in the expanding phase of (26)but not in its collapsing phase.The explanation is simple:in general the expanding and collapsing phases of the elliptic solution are not time-symmetric,as in the homogeneous FLRW case,therefore y =1will also be reached in the collapsing phase but it will not (in general)correspond to a single hypersurface t =constant.Figure 1illustrates this feature.

IV.VOLUME A VERAGES AND CONTRAST FUNCTIONS ALONG THE INITIAL HYPERSURF ACE.

The de?nitions (16)and (17)of the initial value functions ρi and

(3)

R i lead to the following integrals

M (r )=

4πG 2Y i

r

r c

(3)

R i Y 2i Y ′i dr

(36)

where the lower integration limits in these integrals have been ?xed by the conditions M (r c )=K (r c )=0,where r 1=r c marks a Symmetry Center

1

See section V A for more details.See the Appendix for a formal de?ntition of a Symmetry Center

Appendix).For the remaining of this paper we shall assume,unless explicitly speci?ed otherwise,that the spacetime manifold admits at least one SC and so the integrals(35)and(36)become functions that depend only on the upper integration limit r.

Since4π Y2i Y′i dr is the volume associated with the orbits of SO(3)in the hypersurface T i(though it is not a proper volume related to(A12)),equations(35)and(36)suggest then the introduction of the following volume averages

ρi (r)= rρi Y2i Y′i dr Y3i,(37)

(3)R i (r)= r(3)R i Y2i Y′i dr Y2i,(38) In terms of these volume averages the variablesμandκin(23)and(24)become

μ=

4πG

6 (3)R i ,(40) Settingρi and(3)R i to constants in equations(37)and(38)yieldsρi= ρi and(3)R i= (3)R i ,therefore the comparison betweenρi,(3)R i and ρi , (3)R i must provide a“gauge”that measures the inhomogeneity ofρi and (3)R i in the closed interval r≥r c.This motivates de?ning the following“inhomogeneity gauges”or contrast functions

?(m)

i

=

ρi

(3)R i ?1,?(3)R i= (3)R i 1+?(k)i ,(42)

These functions can be expressed in terms of M,K,μandκand their radial gradients.For example:??(m)i and?(k)i in terms ofμ,M,κ,K

1+?(m)

i =

4πG

μ

=

4πG

M

,

1+?(k)i=(3)R i

6K

,(43)

??(m)i and?(k)i in terms ofμ′,M′,κ′,K′and Y′i

1+?(m)

i =

M′/M

3Y′i/Y i

=?(m)

i

,(44)

1+3

2Y′i/Y i

,

κ′/κ

M?3

K

=

μ′

2

κ′

Y i ?(m)i?3

V.GENERIC PROPERIES OF THE NEW V ARIABLES

We discuss in this section the regularity properties and generic features of the new variables,as well as their relation with M ,K de?ned by (37),(38).The averages and contrast functions,(41)and (42),are examined in section VI.Frequent reference will be made to expressions presented and summarized in the Appendix.

A.Initial hypersurfaces.

A hypersurface T i is the 3-dimensional submanifold obtained by restricting an LT

B spacetime to t =t i .This submanifold can be invariantly characterized as the set of rest frames of comoving observers associated with proper time t =t i (see the Appendix).Its induced 3-dimensional metric is

ds 2i =

Y ′2

i

6

(3)

R i Y 2

i =

(3)

R i

√

1+?(k )

i

+

1

From their de?nition in (16),(17)and (15),the functions ρi ,(3)R i ,Y i satisfy the same regularity and di?er-entiability conditions as ρ,(3)R ,Y in the radial direction (see the Appendix):Y i ≥0must be continuous and

ρi ≥0,(3)R i can be piecewise continuous but with a countable number of ?nite jump discontinuities.The average functions, ρi , (3)R i ,constructed from intergration of ρi ,(3)R i ,will be,in general continuous (like

M and K ).The contrast functions,?(m )

i and ?(k )i ,explicitly contain ρi and (3)R i (from (43)),hence they are,at least,piecewise continuous.?Zeroes of Y i and Y ′i .

.

Let r =r c mark a SC (see the Appendix).The functions Y i ,ρi ,(3)

R i ,from their de?nitions in (15),(16)

and (17),must satisfy

Y i(r c)=0,Y′i(r c)=S i=0,Y i≈S i(r?r c)

ρi(r c)>0ρ′i(r c)=0ρi≈ρi(r c)+1

2

(3)R′′i(r c)(r?r c)2

(3)R i(r c)=0(3)R′i(r c)=0(3)R i(r)=0,parabolic dynamics

(50)

where S i=S(t i)=Y′(t i,r c)>0and the fourth subcase above denotes the case of parabolic dynamics in which the condition K=κ=0holds in an interval r c≤r,thus implying that(3)R i(r)=0for all the interval.The central behavior of M,K in(35)and(36)is given by the leading terms

M≈

4πG

6

(3)R i(r c)S2i(r?r c)2,(51)

From(23),(24),(39),(40),(41)and(42),the value ofμ,κand the remaining initial value functions at r=r c are given by

μ(r c)=4πG

6

(3)R i(r c),

ρi (r c)=ρi(r c), (3)R i (r c)=(3)R i(r c),??(m)i(r c)=?(k)i(r c)=0,(52)–Signs and turning values of Y′i.

S i ,y(t,r)≈

S(t)

a SC that might not even be contained in the spacetime manifold.The di?erence between y and Y is illustrated in ?gures2displaying parametric3d plots Y(t,r)and y(t,r)for various LTB models.These?gures clearly show that y(t i)=1for all layers.

From(A8),the gradient Y′/Y is singular at a SC,however,from(21),(22)and(55),we have

Γ(t,r c)=1,ρ(t,r c)=ρi(r c)S3i

S(t)

(57)

while the coordinate locus for shell crossing singularities can be given as

Γ=0,ρi>0,Shell crossing singularity.(58) a characterization that avoids the ambigueity of Y′=0,since,as mentioned in the Appendix,Y′might vanish and change sign regularly for a single r=r?=r c if(A9)holds,preventing surface layers.This situation is now taken

care by conditions(54)acting on Y′i.

C.The function Y i:choice of topology and radial coordinate.

From the common geometric meaning of Y and Y i(see Appendix),it is evident that the homeomorphic class (“open”or“closed”topology)of the regular hypersurfaces of constant t follows from the homeomorphic class of T i. The latter can be determined by applying(A12)to(47)for a given choice of Y i(r),along the domain of regularity of r limited between SC’s(real roots of Y i(r)=0)and/or a maximal value r max de?ned by(49).Because we can always rescale r,it is always possible to select this coordinate so that Y i takes the simplest form,hence the freedom to select Y i can also be the freedom to?nd a convenient radial coordinate for a desired LTB con?guration.As mentioned in the Appendix,the compatibility of any one of the possible choices of homeomorphic class with any one of the three choices of dynamical evolution(parabolic,hyperbolic or elliptic)is only restricted by the regularity conditions(48), (54)and(49).We ellaborate these issues below looking separately the case with one and two SC’s.

?One symmetry center.

Let the centers be marked by r=r c1and r=r c2.Then Y i(r c1)=Y i(r c2)=0,so that Y′i vanishes for some r?in the open interval r c1

The hypersurface T i is homeomorphic to a3-sphere,S3.

D.Invariant expressions.

The volume averages and contrast functions introduced in section IV were constructed by averagingρi and(3)R i with the volume(4/3)πY3i=4π Y2i Y′i dr,a quantity that can be related to the proper area,4πY2i,of the group orbits of SO(3).However,it can be argued that these volume averages and contrast functions are coordinate dependent expressions.We can show that these quantities are equivalent to coordinate independent expressions given in terms of invariant scalars evaluated along T i.From(A4)and(A5)applied to t=t i,together with(41),we obtain

8πG

c 4

ρi +6[ψ2]i =R i +6[ψ2]i 1+?(m )

i

=

4πG ρi

R i +6[ψ2]i

,

(59)

where R i and [ψ2]i are the 4-dimensional Ricci scalar

and the

conformal

invariant

ψ2

evaluated

at

t

=

t

i

.

The evolution equation

(20)applied

to

t

=t i ,together with (A2),(A3),(39),(40),(42)and (59)yields

c 22(3)

R i ?6σi

σi +

Θi 3

2,1+

?(k )

i

=c 2R i +3[σ2

i ?(1

c 2

R i +6c 2[ψ2]i ?(σi +

1

c 2(3)R i ?12σi (σi +

1

(1?K )?1/2Y 2i Y ′i dr

,

(3)

R i (1?K )?1/2Y 2i Y ′i dr

.If for all the domain of regularity of r we have ρi =ρ(0)

i and

(3)

R i =(3)R (0)i ,where ρ(0)

i ≥0and

(3)R (0)

i

are constants,then equations (37),(38),(41)and (42)imply

ρi = ρi =ρ(0)

i ,

?

?(m )

i

=0,M =

4πG

6

(3)

R (0)

i Y 2i ,

(62)

Since μand κin (23)and (24)are now constants,y (determined by (20))must be a function of t only,and so,from (18)and (22),we have Γ=1and Y =(S (t )/S i )Y i ,identifying y =S (t )/S i with an adimensional FLRW

scale factor.Rest mass density and scalar 3-curvature take the FLRW forms:ρ=ρ(0)

i (S i /S )3and (3)R =(3)

R (0)

i (S i /S )2,while the metric (19)becomes a FLRW metric if we identify Y i =S i r so that (1/6)(3)R (0)i S 2i

becomes an adimensional curvature index.Equations (62)rea?rm the role of inhomogeneity gauges for ?(m )

i

and ?(k )

i ,making also evident that initial conditions with homogeneous ρi and (3)R i leads only to FLRW evolution.

?Schwarzschild limit

Y 3i

r

ρ′

i Y 3i dr

?(m )i

=

r

ρ′i Y 3i dr

See ?gures

3a and 3b.

In

this case a density “lump”or “void”is characterized by ρi having a maximum/minimum at the center

worldline r =r c .Hence,for a lump or void,we have (from (64))the following possible ranges of ?(m )

i

initial lump:

ρ′i ≤0,

ρi ≤ ρi ,

?

?1≤?(m )

i ≤0,initial void:

ρ′i ≥0,

ρi ≥ ρi ,

?

?(m )

i

≥0,

(65)

where the lower bound on ?(m )

i for a lump is ?(m )

i

=?1if ρi vanishes for r >r c (from(41)).

?Two symmetry centers.

3c 4

r c 2

r c 1

ρi Y 2i Y ′i dr =0

(66)

Therefore,for every r =a in the open domain r c 1

a

r c 1

ρi Y 2i Y ′i dr =?

r c 2a

ρi Y 2i Y ′i dr = a r c 2

ρi Y 2i Y ′i dr (67)

Since Y i vanishes at both SC’s,this means that,for whatever ρi we choose,the average ρi evaluated from one

center (say r =r c 1)to r =a must be the same as that average evaluated from the other center (r =r c 2).Also,following the usual interpretation of M as the “e?ective mass inside”a comoving layer r ,this “e?ective mass”for the whole hypersurface (from r =r c 1ro r =r c 2)is zero.

We have two possible regular con?gurations (see ?gures 3c and 3d),depending whether ρi is:(i)a local maximum at each center (each center is a density lump)and (ii)a local minimum at each center (each center is a density

void).For each case,?(m )

i vanishes at the centers,while (from (64))and using the same arguments as in the case of one center,we have for the cases (a)and (b).

an initial lump in each center:ρi ≤ ρi ,

?

?1≤?(m )

i ≤0,an initial void in each center:

ρi ≥ ρi ,

?

?(m )

i

≥0,

(68)

If allow ρi ′to change its sign in a given domain containing a SC,we obtain an initial density that can be associated

with “density ripples”(see ?gure 6a).In this case we have ?1≤?(m )

i ≤0for all r for which ρi ′is negative and ?(m )

i ≥0for positive ρi ′.

B.Initial curvature lumps and voids.

Unlike ρi ,the intial 3-curvature (3)R i can be zero,positive,negative or change signs in any given domain of r .This

makes the relation between (3)R i , (3)R i ,K and ?(k )

i more complicated than in the case of ρi .Also,the regularity conditions (48)and (54),as well as the distinction between the type of dynamics (parabolic,hyperbolic or elliptic),all involve speci?c choices of (3)R i and K but not of ρi and M .

The following auxiliary relation,analogous to (64),follows from integration by parts of (38)

(3)

R i ? (3)R i =

1

3

≤?(k )

i ≤0,

curvature voids:

(3)

R i ≥ (3)R i ,

?(k )

i

≥0,

(70)

where the minimal value ?2/3follows from K >0and from the regularity of the left hand side in (45).Notice that condition (48)is not trivialy satis?ed.We examine below the cases with one and two SC’s.

–One SC.(See ?gure 4a).

From

(36)

and (51),

the

functions Y i and K vanish at the center and increase as r →r max ,but (48)requires that K ≤1for all the domain of r .Condition (54)can be avoided by selecting Y i =S i r so that Y ′i never vanishes.Necessary and su?cient condition for complying with (48)and (49)are

(3)

R i →0and K =

1

2Y i (r ?)

r ?

r c 1(3)

R i Y 2i Y ′i dr =K (r ?)=1,

(72)

The graphs of (3)R i , (3)R i ,K and ?(k )

i are shown in ?gures 4and qualitatively analogous to those of

ρi , ρi ,M and ?(m )

i in ?gures 3.The function K must vanish at the SC’s (like M )and comply with (72).

?

(3)

R i <0for a domain of r containing a SC.(See ?gures 5a and 5b).

In this case we have (3)R i and K negative for all the domain of r ,condition (48)holds trivialy and dust layers follow hyperbolic dynamics.However,the characterization of “lump”or “void”in terms of the sign of (3)R ′i is

the inverse to that when (3)R i is nonegative:lump and void are now respectively characterized by (3)R ′

i >0

and (3)R i <0.Besides this point,the range of values of ?(k )

i for lumps and is the same as for the non-negative case in (70).

?

(3)

R i changes sign but K and (3)R i do not.(See ?gure 6b).

Since (3)R i and K are obtained from an integral involving (3)R i evaluated from a SC to a given r ,it is quite possible to have situations in which (3)R i vanishes or pases from positive to negative (or viceverza)but (3)R i and K remains positive (or negative)at least for an interval of the domain of r not containing a SC,so that the model remains elliptic or hyperbolic in this domain.The situation in which (3)R i or K vanish for a given r =r ?in an open domain of r that excludes a SC is qualitatively di?erent and more complicated,since the dynamic evolution of dust layers (governed by (3)or (20))passes from elliptic to parabolic or hyperbolic (or viceverza).This case will be examined in a separate paper [29].

VII.THE FUNCTION Γ,SHELL CROSSING SINGULARITIES AND BANG TIMES.

The function Γde?ned in (22)is essential for calculating relevant quantities characterizing LTB solutions,such as ρ,Θ,σ,(3)R and ψ2((A1),(A2),(A3),(A5)and (21)).The exact functional form of Γis also required in order to ?nd the restrictions on initial conditions that ful?l the important regularity condition:

Γ≥0

for ρi ≥0and K =1,

(73)

with Γ=0only if ρi =0and/or 1?K =0.This condition garantees that:(a)the metric coe?cient g rr is regular,(b)ρ≥0for a given choice of ρi ≥0and (c)provides the necessary and/or su?cient restrictions on initial value functions in order to avoid shell crossing singularities (these conditions are summarized in Table 1).We show in this section that the conditions for avoiding these singularities based on (73)are equivalent to those found by Hellaby and Lake [15](see also [16]and [17]).

The function Γcan be obtained in terms of y and the initial value functions μ,κ,?(m )

i ,?(k )i by eliminating y ′/y from an implicit derivation with respect to r of equations (25),(26),(27)and (31).For hyperbolic and elliptic

dynamics,Γin terms ofηfollows from implicit derivation of(29)and(33),using(28),(32),(30)and(34)in order to eliminateη′in terms of y′/y.We provide below the most compact forms of this function for parabolic solutions(in terms of y)and for hyperbolic and elliptic solutions(in terms ofη)

Γ=1+?(m)

i??(m)

i

P i ?3P[Q?Q i]

?(m)i?3

(coshη?1)2=

√

(x y)3/2

,

Q(η)=sinhη?η=

2+x

x(2+x)?arccosh(1+x),η=arccosh(1+x y)≥0,ηi=arccosh(1+x)≥0,x≡|κ| (1?cosη)2

= (x y)2=±√(x y)3/2,

Q(η)=η?sinη=arcsin(1?x y)?

2?x

x(2?x),η=arccos(1?x y),0≤η≤2π

ηi=arccos(1?x),0<ηi<π,x≡

κ

t i ?t bb <0,

for collapsing layers .(80)

These regularity considerations provide an insight on the relation of the “bang time”t bb with the initial value functions ρi ,(3)R i and their corresponding average and contrast functions.From the forms of t bb that will be obtained in this section and displayed in ?gures 7,the fact that t ′bb =0leads to an r dependent “age di?erence”for the comoving observers,a di?erence whose maximal value is very sensitive to ?(m )

i and ?(k )

i ,and so to the ratios of maximal to minimal ρi and (3)R i (but not to local values ρi or (3)R i ).This feature is illustrated in ?gures 7.

The ful?lment of conditions (73),as well as a comparison with no-shell-crossing conditions of Hellaby and Lake [15],is examined below for the cases with parabolic,hyperbolic and elliptic dynamics.

A.Parabolic solutions.

From (74)and (73),shell crossing singularities are avoided if

(1+

?(m )

i )y 3/2

?

?(m )i

≥0?y

3/2

≥

?(m )

i

3

√

3

√

μ

=

12μ

Y ′i

B.Hyperbolic solutions.

In order to examine the ful?lment of(73),we assume thatρi≥0and(3)R i≤0and rewrite(75)as

Γ=1+3 A?(m)i?B?(k)i ?3P

2

P(η)Q(η),A i=A(ηi),B i=B(ηi),(87)

where P(η)and Q(η)are given by(76).The ful?lment of(73)obviously depends on the behavior of A,B and P in the full rangeη≥0.We have P≥0with P→∞asη→0,while in the same limit A→2/3and B→0. Therefore,the following are necessary conditions for(73)

A i?(m)

i?B i?(k)i≤0,(88)

1+3 A?(m)i?B?(k)i ≥0,(89)

However,A and B satisfy0

ρi≥0,(3)R i≤0,?1≤?(m)i≤0,?2

|κ|3/2=c t i?1

|κ|

1+2x ,x≡|κ|

Y i

μ

that might also violate the no-shell-crossing conditions(see?gures7a and7b),since divergingρi and

|

(3)

R

i

|can

be associated with for voids with large values of?(m)

i

and?(k)i.Hence,a regular hypersurfaces T i always exist for physicaly reasonable intial conditions and a‘good’selection of functions M,E=?K,t

bb

leads to‘good’forms of (3)R i,ρi,Y i.However,we argue again,that?nding a‘good’choice of the latter is easier and more intuitive.

Shell crossing singularities will always emerge for initial conditions with density and/or3-curvature voids(see?gure 7b),however for reasonable initial conditions characterized by?niteρi≥0and(3)R i≤0,we must have?niteμ>0 andκ<0in all T i(see section VIII for examples).Thus,unless we choose pathological initial value functions as in ?gure8,quantities like P i and Q i de?ned in(77)will be?nite and non-zero,leading toΓ→1?(3/2)?(k)i asη→∞asymptoticaly,therefore a regular evolution of intial voids is possible in the domain t≥t i as long as?(k)i≤2/3 (for expanding layers).An LTB model with initial voids and hyperbolic dynamics following this type of evolution is depicted in?gure11a.

C.Elliptic solutions.

As with the hyperbolic case,we assume thatρi≥0and(3)R i≥0and rewrite(75)as

Γ=1+3(?(m)

i??(k)i)?3P Q ?(m)i?3P i A i?(m)i?B i?(k)i ,(94)

A i=1?P i Q i,

B i=1?

3

2

?(k)i +A i?(m)i?B i?(k)i=(2π?Q i)P i ?(m)i?3

2

?(k)i≥0,(97) Following the arguments of Hellaby and Lake[15],we prove the su?ciency of(95)and(96)by assuming that

1+3 ?(m)i??(k)i =3α(ηi) ?(m)i?3

2

?(k)i=?

β(ηi)

P i

[β(α?P Q)+P],

and the ful?lment ofΓ≥0requires(95)andβ≥?P/(α?P Q).However,from the forms of P and Q in(94),this latter condition can only be satis?ed in the whole evolution range0<η<2πif the functionsα,βsatisfyα≥2/3

andβ≥1/(2π).Inserting these inequalities into(98)we obtain(96)together with?(m)

i≥?1.Conditions(95)and (96)are then necessary and su?cient,but we still need to test the compatibility of these conditions with the signs

of?(m)

i

and?(k)i(initial lumps or voids).Clearly,(95)is compatible with either?(m)

i≤0and?(k)i≥0(density

lump and 3-curvature void)or with ?(m )i ≤0and ?(k )

i ≤0(density and 3-curvature lumps).However,(96)is

only

compatible

with the

second choice.

Therefore,

the

full set of

necessary

and

su?cient

conditions

for

avoiding

shell crossing

singularities

are (97),

together

with

?2

2

?(k )i

≥P i Q i

?(m )

i ?

3K 3/2

M ′

2

K ′

κ3/2

=c t i ?

1κ

arccos (1?x )

x

?1

1/2

,

0≤κ≤2μ,

x ≡

κ

Y i

μ2μ)as κ→0.On the other hand,the big

crunch time is c t bc =c t bb +2πμ/κ3/2

.Therefore,conditions (80)can only be violated if both κand μdiverge but complying with 0≤κ/μ≤2,a situation that can be avoided if both μand κor ρi and (3)R i are ?nite.As shown by ?gures 7c,7d and 7e,conditions (80)are satis?ed for reasonable initial value functions,even in the cases displayed in 7d and 7e in which shell crossing occur.In general,a ‘good’selection of functions M,K =?E,t bb leads to ‘good’forms of (3)R i ,ρi ,Y i and viceverza.

As with parabolic and hyperbolic solutions,initial conditions with density and/or 3-curvature voids lead,in general,to shell crossings but a regular evolution with these type of initial conditions is possible in the domain t ≥t i .In order to illustrate this point,we consider Γgiven by (75)and assume that ρi ≥0and (3)R i ≥0are everywhere ?nite (in order to comply with (80)).Bearing in mind that:3P (Q i ?Q )≥?2and 1?P/P i ≥0for η≥ηi (or t ≥t i ),a su?cient condition for Γ≥0is given by

?(k )

i

≤?(m )

i

≤

1

2

?(k )

i ,

(104)

This condition is illustrated graphicaly by ?gure 9c,leading to the model displayed in ?gure 11b,an elliptic LTB model with an initial density void that has a regular evolution for t ≥t i .

D.Simmultaneous big bang.

An important special class of initial conditions is that characterized by a simmultaneous big bang:ie y =0taking place in a singular hypersurface marked by t =constant.The conditions for a

symmultaneous

big

bang readily follow by setting t ′bb

=0in (85),(93)and (103).Clearly,a symmultaneous big bang is incompatible with parabolic solutions,since t ′bb

=0in (85)implies ?(m )

i =0,but this case is the FLRW limit (see section V E).From (93)and (103),a symmultaneous big bang for hyperbolic and elliptic solutions implies the vanishing of the term in square brackets in the right hand sides of (86)and (94),that is

A i ?(m )

i

=B i ?(k )

i ,

(105)

so that Γbecomes

Γ=1+3

A ?(m )i ?B

?(k )i

(106)

The conditions for avoiding shell crossings depend on the forms of A and B given by (86)and (94).We assume that ρi ≥0and (3)R i ≥0(elliptic)and (3)R i ≤0(hyperbolic)are all ?nite and examine the hyperbolic and elliptic cases below:

?For hyperbolic solutions,both A and B are monotonously decreasing with 0≤A ≤1/3and ?1/2≤B ≤0,while A →1/3,B →0as η→0and A →0,B →?1/2as η→∞.For the asymptotic limits,η≈0and η→∞,

we have respectively Γ≈1+?(m )

i and Γ≈1+(3/2)?(k )i .Since A i and B i have also opposite signs,these asymptotic limits,together with (105),lead to the following necessary conditions for avoiding shell crossings

?(m )

i

≥?1,?(k )

i

≥?

2

2+x √

2+x ?arccosh (1+x )

2

√x

√

x

1/2

?

arccosh (1+x )

2

?(k )

i

≥0,?(m )

i

?(k )

i

≥0,

(110)

As with the hyperbolic case,for t bb =t (0)bb

i ,?(k )

i

follow

from (102)and (105)

?(k )i =x 3/2

?√x √x 3/2?32?x arccos (1?x )?√2?x

?(m )

i

,(111)

1κ

arccos (1?x )

x ?1

1/2

=c (t i ?t (0)bb

),(112)

对翻译中异化法与归化法的正确认识

对翻译中异化法与归化法的正确认识 班级：外语学院、075班 学号：074050143 姓名：张学美 摘要：运用异化与归化翻译方法,不仅是为了让读者了解作品的内容,也能让读者通过阅读译作,了解另一种全新的文化,因为进行文化交流才是翻译的根本任务。从文化的角度考虑,采用异化法与归化法,不仅能使译文更加完美,更能使不懂外语的人们通过阅读译文,了解另一种文化,促进各民族人们之间的交流与理解。翻译不仅是语言符号的转换,更是跨文化的交流。有时,从语言的角度所作出的译文可能远不及从文化的角度所作出的译文完美。本文从翻译策略的角度，分别从不同时期来说明人们对异化法与归化法的认识和运用。 关键词:文学翻译；翻译策略；异化；归化；辩证统一 一直以来,无论是在我国还是在西方,直译(literal translation)与意译(liberal translation)是两种在实践中运用最多,也是被讨论研究最多的方法。1995年,美籍意大利学者劳伦斯-韦努蒂(Lawrence Venuti)提出了归化(domestication)与异化(foreignization)之说,将有关直译与意译的争辩转向了对于归化与异化的思考。归化与异化之争是直译与意译之争的延伸,是两对不能等同的概念。直译和意译主要集中于语言层面,而异化和归化则突破语言的范畴,将视野扩展到语言、文化、思维、美学等更多更广阔的领域。 一、归化翻译法 Lawrwnce Venuti对归化的定义是,遵守译入语语言文化和当前的主流价值观,对原文采用保守的同化手段,使其迎合本土的典律,出版潮流和政治潮流。采用归化方法就是尽可能不去打扰读者,而让作者向读者靠拢(the translator leaves the reader in peace, as much as possible, and moves the author towards him)。归化翻译法的目的在于向读者传递原作的基本精神和语义内容,不在于语言形式或个别细节的一一再现。它的优点在于其流利通顺的语言易为读者所接受,译文不会对读者造成理解上的障碍,其缺点则是译作往往仅停留在内容、情节或主要精神意旨方面,而无法进入沉淀在语言内核的文化本质深处。 有时归化翻译法的采用也是出于一种不得已,翻译活动不是在真空中进行的,它受源语文化和译语文化两种不同文化语境的制约,还要考虑到两种文化之间的

翻译中的归化与异化

“异化”与“归化”之间的关系并评述 1、什么是归化与异化 归化”与“异化”是翻译中常面临的两种选择。钱锺书相应地称这两种情形叫“汉化”与“欧化”。A．归化 所谓“归化”（domestication 或target-language-orientedness），是指在翻译过程中尽可能用本民族的方式去表现外来的作品；归化翻译法旨在尽量减少译文中的异国情调，为目的语读者提供一种自然流畅的译文。Venuti 认为，归化法源于这一著名翻译论说，“尽量不干扰读者，请作者向读者靠近” 归化翻译法通常包含以下几个步骤：（1）谨慎地选择适合于归化翻译的文本；（2）有意识地采取一种自然流畅的目的语文体；（3）把译文调整成目的语篇体裁；（4）插入解释性资料；（5）删去原文中的实观材料；（6）调协译文和原文中的观念与特征。 B．“异化”（foreignization或source-language-orientedness）则相反，认为既然是翻译，就得译出外国的味儿。异化是根据既定的语法规则按字面意思将和源语文化紧密相连的短语或句子译成目标语。例如，将“九牛二虎之力”译为“the strength of nine bulls and two tigers”。异化能够很好地保留和传递原文的文化内涵，使译文具有异国情调，有利于各国文化的交流。但对于不熟悉源语及其文化的读者来说，存在一定的理解困难。随着各国文化交流愈来愈紧密，原先对于目标语读者很陌生的词句也会变得越来越普遍，即异化的程度会逐步降低。 Rome was not built in a day. 归化:冰冻三尺,非一日之寒. 异化:罗马不是一天建成的. 冰冻三尺,非一日之寒 异化:Rome was not built in a day. 归化:the thick ice is not formed in a day. 2、归化异化与直译意译 归化和异化，一个要求“接近读者”，一个要求“接近作者”，具有较强的界定性；相比之下，直译和意译则比较偏重“形式”上的自由与不自由。有的文中把归化等同于意译，异化等同于直译，这样做其实不够科学。归化和异化其实是在忠实地传达原作“说了什么”的基础之上，对是否尽可能展示原作是“怎么说”，是否最大限度地再现原作在语言文化上的特有风味上采取的不同态度。两对术语相比，归化和异化更多地是有关文化的问题，即是否要保持原作洋味的问题。 3、不同层面上的归化与异化 1、句式 翻译中“归化”表现在把原文的句式（syntactical structure）按照中文的习惯句式译出。

翻译的归化与异化

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翻译的归化与异化 作者：熊启煦 作者单位：西南民族大学,四川,成都,610041 刊名： 西南民族大学学报（人文社科版） 英文刊名：JOURNAL OF SOUTHWEST UNIVERSITY FOR NATIONALITIES（HUMANITIES AND SOCIAL SCIENCE） 年，卷(期)：2005,26(8) 被引用次数：14次 参考文献(3条) 1.鲁迅且介亭杂文二集·题未定草 2.刘英凯归化--翻译的歧路 3.钱钟书林纾的翻译 引证文献(15条) 1.郭锋一小议英语翻译当中的信达雅[期刊论文]-青春岁月 2011(4) 2.许丽红论汉英语言中的文化差异与翻译策略[期刊论文]-考试周刊 2010(7) 3.王笑东浅谈汉英语言中的差异与翻译方法[期刊论文]-中国校外教育（理论） 2010(6) 4.王宁中西语言中的文化差异与翻译[期刊论文]-中国科技纵横 2010(12) 5.鲍勤.陈利平英语隐喻类型及翻译策略[期刊论文]-云南农业大学学报(社会科学版) 2010(2) 6.罗琴.宋海林浅谈汉英语言中的文化差异及翻译策略[期刊论文]-内江师范学院学报 2010(z2) 7.白蓝跨文化视野下文学作品的英译策略[期刊论文]-湖南社会科学 2009(5) 8.王梦颖探析汉英语言中的文化差异与翻译策略[期刊论文]-中国校外教育（理论） 2009(8) 9.常晖英汉成语跨文化翻译策略[期刊论文]-河北理工大学学报（社会科学版） 2009(1) 10.常晖对翻译文化建构的几点思考[期刊论文]-牡丹江师范学院学报（哲学社会科学版） 2009(4) 11.常晖认知——功能视角下隐喻的汉译策略[期刊论文]-外语与外语教学 2008(11) 12.赵勇刚汉英语言中的文化差异与翻译策略[期刊论文]-时代文学 2008(6) 13.常晖.胡渝镛从文化角度看文学作品的翻译[期刊论文]-重庆工学院学报(社会科学版) 2008(7) 14.曾凤英从文化认知的视角谈英语隐喻的翻译[期刊论文]-各界 2007(6) 15.罗琴.宋海林浅谈汉英语言中的文化差异及翻译策略[期刊论文]-内江师范学院学报 2010(z2) 本文链接：https://www.doczj.com/doc/d38895925.html,/Periodical_xnmzxyxb-zxshkxb200508090.aspx

归化与异化翻译实例

翻译作业10 Nov 15 一、请按归化法(Domestication)翻译下列习语。 Kill two birds with one stone a wolf in sheep’s clothing strike while the iron is hot. go through fire and water add fuel to the flames / pour oil on the flames spring up like mushrooms every dog has his day keep one’s head above water live a dog’s life as poor as a church mouse a lucky dog an ass in a lion’s skin a wolf in sheep’s clothing Love me, love my dog. a lion in the way lick one’s boots as timid as a hare at a stone’s throw as stupid as a goose wet like a drown rat as dumb as an oyster lead a dog’s life talk horse One boy is a boy, two boys half a boy, and three boys nobody. Man proposes, God disposes. Cry up wine and sell vinegar (cry up, to praise; extol: to cry up one's profession) Once bitten, twice shy. An hour in the morning is worth two in the evening． New booms sweep clean. take French leave seek a hare in a hen’s nest have an old head on young shoulder Justice has long arms You can’t teach an old dog Rome was not built in a day. He that lives with cripples learns to limp. Everybody’s business is nobody’s business. The more you get, the more you want. 二、请按异化法(foreignization)翻译下列习语。 Kill two birds with one stone a wolf in sheep’s clothing

翻译术语归化和异化

归化和异化这对翻译术语是由美国著名翻译理论学家劳伦斯韦努蒂（Lawrence Venuti）于1995年在《译者的隐身》中提出来的。 归化：是要把源语本土化，以目标语或译文读者为归宿，采取目标语读者所习惯的表达方式来传达原文的内容。归化翻译要求译者向目的语的读者靠拢，译者必须像本国作者那样说话，原作者要想和读者直接对话，译作必须变成地道的本国语言。归化翻译有助于读者更好地理解译文，增强译文的可读性和欣赏性。 异化：是“译者尽可能不去打扰作者，让读者向作者靠拢”。在翻译上就是迁就外来文化的语言特点，吸纳外语表达方式，要求译者向作者靠拢，采取相应于作者所使用的源语表达方式，来传达原文的内容，即以目的语文化为归宿。使用异化策略的目的在于考虑民族文化的差异性、保存和反映异域民族特征和语言风格特色，为译文读者保留异国情调。 作为两种翻译策略，归化和异化是对立统一，相辅相成的，绝对的归化和绝对的异化都是不存在的。在广告翻译实践中译者应根据具体的广告语言特点、广告的目的、源语和目的语语言特点、民族文化等恰当运用两种策略，已达到具体的、动态的统一。 归化、异化、意译、直译 从历史上看，异化和归化可以视为直译和意译的概念延伸，但又不完全等同于直译和意译。直译和意译所关注的核心问题是如何在语言层面处理形式和意义，而异化和归化则突破了语言因素的局限，将视野扩展到语言、文化和美学等因素。按韦努蒂（Venuti）的说法，归化法是“把原作者带入译入语文化”，而异化法则是“接受外语文本的语言及文化差异，把读者带入外国情景”。（Venuti，1995:20）由此可见，直译和意译主要是局限于语言层面的价值取向，异化和归化则是立足于文化大语境下的价值取向，两者之间的差异是显而易见的，不能混为一谈。 归化和异化并用互补、辩证统一 有些学者认为归化和异化，无论采取哪一种都必须坚持到底，不能将二者混淆使用。然而我们在实际的翻译中，是无法做到这么纯粹的。翻译要求我们忠实地再现原文作者的思想和风格，而这些都是带有浓厚的异国情调的，因此采用异化法是必然；同时译文又要考虑到读者的理解及原文的流畅，因此采用归化法也是必然。选取一个策略而完全排除另一种策略的做法是不可取的，也是不现实的。它们各有优势，也各有缺陷，因此顾此失彼不能达到最终翻译的目的。 我们在翻译中，始终面临着异化与归化的选择，通过选择使译文在接近读者和接近作者之间找一个“融会点”。这个“融会点”不是一成不变的“居中点”，它有时距离作者近些，有时距离读者近些，但无论接近哪

翻译中的归化与异化

姓名：徐中钧上课时间：T2 成绩： 翻译中的归化与异化 归化与异化策略是我们在翻译中所采取的两种取向。归化是指遵从译出语文化的翻译策略取向，其目的是使译文的内容和形式在读者对现实了解的知识范围之内，有助于读者更好地理解译文，增强译文的可读性。异化是指遵从译入语文化的翻译策略取向，其目的是使译文保存和反映原文的文化背景、语言传统，使读者能更好地了解该民族语言和文化的特点。直译和意译主要是针对的是形式问题，而归化和异化主要针对意义和形式得失旋涡中的文化身份、文学性乃至话语权利的得失问题，二者不能混为一谈。 在全球经济一体化趋势日益明显的今天，人们足不出门就能与世界其他民族的人进行交流。无论是国家领导人会晤、国际经济会议，还是个人聚会、一对一谈话，处于不同文化的两个民族都免不了要进行交流。如果交流的时候不遵从对方的文化背景，会产生不必要的误会，造成不必要的麻烦。在2005年1月20 日华盛顿的就职典礼游行活动中，布什及其家人做了一个同时伸出食指和小指的手势。在挪威，这个手势常常为死亡金属乐队和乐迷使用，意味着向恶魔行礼。在电视转播上看到了这一画面的挪威人不禁目瞪口呆，这就是文化带来的差异。人们日常生活中的习语、修辞的由于文化差异带来的差别更是比比皆是，如以前的“白象”电池的翻译，所以文化传播具有十分重要的意义。由此可见，借助翻译来传播文化对民族间文化的交流是很有必要的。 一般来说，采取归化策略使文章变得简单易懂，异化使文章变得烦琐难懂。归化虽然丢掉了很多原文的文化，但使读者读起来更流畅，有利于文化传播的广度。采取异化策略虽然保存了更多的异族文化，能传播更多的异族文化，有利于文化传播的深度，但其可读性大大降低。归化和异化都有助于文化的传播，翻译时应注意合理地应用归化与异化的手段。对于主要是表意的译文，应更多地使用归化手段，反之则更多地使用异化手段。 要使翻译中文化传播的效果达到最好，译者应该考虑主要读者的具体情况、翻译的目的、译入文的内容形式等具体情况而动态地采取归化与异化的手段。 文章字符数：920 参考文献： 论异化与归化的动态统一作者：张沉香（即讲义） 跨文化视野中的异化/归化翻译作者：罗选民https://www.doczj.com/doc/d38895925.html,/llsj/s26.htm

翻译的归化与异化

【摘要】《法国中尉的女人》自1969年面世以来，凭借着高度的艺术价值，吸引了国内外学者的眼球。在中国市场上也流传着此书的多个译本，本文就旨在透过《法国中尉的女人》中的两处题词的译作分析在具体翻译文本中如何对待归化与异化的问题。 【关键词】《法国中尉的女人》；题词；归化；异化 一、归化与异化 在翻译领域最早提出归化与异化两个词的学者是美国翻译学者韦努蒂。归化一词在《翻译研究词典》中的定义为：归化指译者采用透明、流畅的风格以尽可能减弱译语读者对外语语篇的生疏感的翻译策略。异化一词的定义为：指刻意打破目的语的行文规范而保留原文的某些异域特色的翻译策略。韦努蒂主张在翻译的过程中更多的使用异化，倡导看起来不通顺的译文，注重突出原文的异域风格、语言特色与文化背景。 二、如何看待归化与异化 鲁迅说对于归化与异化，我们不能绝对的宣称哪种是绝对的好的，另一种是绝对的不好的。翻译的过程中归化与异化是相辅相成互相补充的，具体使用哪种方法不仅需要依据翻译目的以及译文的读者群来判断。这也正是本文对待归化异化的一个态度。下面就通过分析刘蔺译本与陈译本在处理《法国中尉的女人》第五章的引言丁尼生《悼念集》时的例子来具体分析这一点。对于原文 at first as death， love had not been， or in his coarsest satyr-shape had bruised the herb and crush’d the grape， 刘蔺译本将此处翻译为 啊，天哪，提这样的问题 又有保益？如果死亡 首先意味着生命了结， 那爱情，如果不是 在涓涓细流中戛然中止， 就是一种平庸的友情， 或是最粗野的色迷 在树林中肆意饕餮， 全不顾折断茎叶， 揉碎葡萄―― 而此时陈译本却将此诗译作 哦，我啊，提出一个无益的问题 又有何用？如果人们认为死亡 就是生命的终结，那么，爱却不是这样， 否则，爱只是在短暂的空闲时 那懒散而没激情的友谊， 或者披着他萨梯粗犷的外套 已踩伤了芳草，并摧残了葡萄， 在树林里悠闲自在，开怀喝吃。 两篇译作各有千秋，从这首诗整体着眼刘蔺译本更趋向于归化手法，陈译本更倾向于异化处理。刘蔺译本将satyr一词译色迷采用了归化的技巧，而陈译本却将satyr一词译为萨梯，采用了异化的手法。satyr原指人羊合体的丛林之神，其实刘蔺译本与陈译本在处理satyr 时采用不同的方法就是因为翻译目的及读者文化群不同引起的。1986年出的刘蔺译本出版时，

中国旅游文本汉英翻译的归化和异化演示教学

中国旅游文本汉英翻译的归化和异化

中国旅游文本汉英翻译的归化和异化 内容摘要：自改革开放政策执行以来，我国旅游业一直呈现迅速繁荣发展趋势，旅游业在我国国民经济发展中扮演着十分重要的角色。与此同时，旅游类翻译已经被视为一条将我国旅游业引往国际市场的必经之路。为了能够让国外游客更清楚地了解中国的旅游胜地，我们应该对旅游翻译加以重视。尽管国内的旅游资料翻译如同雨后春笋般涌现，但在旅游翻译中仍存在许多问题，尤其是翻译策略的选择问题。归化与异化作为处理语言形式和文化因素的两种不同的翻译策略，无疑对旅游翻译的发展做出了巨大贡献。本文将重点讨论在汉英旅游翻译中，译者该如何正确的处理归化和异化问题，实现归化和异化的有机结合，从而达到理想的翻译水平。从归化与异化的定义、关系、以及归化和异化在旅游翻译中的应用与意义进行论述。 关键词：旅游文本归化翻译异化翻译 关于翻译中归化和异化的定义，国内外的专家学者已经做了很多的描述。为了使得本文读者更好地了解什么是翻译中的归化和异化，作者将介绍这两种翻译方法的关键不同，包括两者的定义以及两者之间的关系。

从他们的定义，很容易找到归化和异化之间的差异。通过对比，这两种策略有各自的目的、优点和语言样式。归化是指翻译策略中，应使作为外国文字的目标语读者尽可能多的感“流畅的风格，最大限度地淡化对原文的陌生感的翻译策略”（Shuttleworth & Cowie，1997：59）。换句话说，归化翻译的核心思想是译者需要更接近读者。归化的目的在于向读者传递最基本精神和内容含义。这种翻译策略明显的优势就是读者可以很容易地接受它流畅的语言风格。例如，济公是个中国神话中的传奇人物。不过，外国人可能没有在这种明确的翻译方式下获得信息。因此，适合的翻译方法是找出西方国家中类似济公这样的人物。因此最终的翻译为：济公是一个中国神话中的传奇人物（类似于西方文化中的罗宾汉）。这样的翻译更容易被目的语读者所接受。“异化是指在在翻译策略中，使译文打破目地语的约束，迁就外来文化的语言特点以及文化差异。”（Venuti，2001：240）这一战略要求“译者尽可能不去打扰作者，让读者向作者靠拢。”（Venuti，1995：19）归化可能保留源语的主要信息。异化的目的是使读者产生一种非凡的阅读体验。异化可以容纳外语的表达特点，将自身向外国文化靠拢，并将特殊的民族文化考虑在内。例如，如果将“岳飞庙和墓”翻译成英语，可以翻译为：“Yue Fei’s

英语论文 归化与异化翻译

2010届本科生毕业设计（论文） 毕业论文 Domestication or Foreignism-oriented Skills in Translation 学院：外国语学院 专业：姓名：指导老师：英语专业 xx 学号： 职称： xx 译审 中国·珠海 二○一○年五月

xx海学院毕业论文 诚信承诺书 本人郑重承诺：我所呈交的毕业论文Domestication or Foreignism-oriented Skills in Translation 是在指导教师的指导下，独立开展研究取得的成果，文中引用他人的观点和材料，均在文后按顺序列出其参考文献，论文使用的数据真实可靠。 承诺人签名： 日期：年月日

Domestication or Foreignism-oriented Skills in Translation ABSTRACT Translation, a bridge between different languages and cultures, plays an indispensable role in cross-culture communication. However, as a translator, we have to choose which strategy to deal with the cultural differences between the source language and the target language in the process of translation where there exists two major translation strategies--- domestication and foreignization. In this thesis, I will discuss these strategies and their application from translation, linguistics, and cross-cultural communication perspectives. In the thesis, I will first talk about the current research of the domestication and foreignization in the translation circle as well as point out the necessity for further research. Then, I will illustrate the relationship between linguistics and translation as well as between culture and translating and next systematically discuss these two translation strategies including their definitions, the controversy in history and their current studies. Besides, I will continue to deal with such neglected factors as may influence the translator’s choice of translation strategies: the type of the source text (ST), the translation purposes, the level of the intended readers, the social and historical background, the translator’s attitude and so on. Finally, from the linguistic and cultural perspectives, the thesis makes a comparative study of the application of domestication and foreignization by analyzing typical examples from the two English versions of Hong Lou Meng translated by Yang Xianyi and David Hawkes respectively. The thesis will conclude that these two translation strategies have their respective features and applicable value. I sincerely hope that this research into translation strategies will enlighten translators and make a little contribution to the prosperity of