discontinuities of critical amplitude for specific heat
TRANSCRIPT
Volume45A,number1 PHYSICSLETTERS 27 August 1973
DISCONTINUITIES OF CRITICAL AMPLITUDE FOR SPECIFIC HEAT
R. ABE andS. HIKAMIDepartmentof PureandAppliedSciences,Universityof Tokyo,Komaba,Meguro-Ku,Tokyo,Japan
Received2 July 1973
Onthebasisof 1/n expansion,the criticalamplitudefor specificheatis shownto bediscontinuousat spacedimen-sionsd= 2 + (2/rn), (m = 2, 3, ... ). This propertyis confirmedup to theorderof 1/n3.
In previouspapers[1], thepresentauthorsdis- andcompareonly (in e )/n terms,one would havecussedananomalousbehaviorof logarithmic termre- = ~ 7~~ This is thepreviouslatedto specificheatexponenta. It wasshownthat result [1]. However,eq.(1) suggeststhat the quantity:the coefficientof logarithmic termof the orderof {&~+.~ 7l(_B)mó(d,dm)}appearsasa common1/n hasdiscontinuitiesat dimensionsd= dm=2 +(2/m), multiplicative factor in thehigherorderterms.If we(m = 2,3,...),in thecaseof short-rangeinteraction, neglectthe 1/n2term of exponenta,eq.(1) is con-We interpretedthis anomalyasdiscontinuitiesof aat sistentwith thefollowing form:d= drn. However,thereremainsanotherpossibilitythat the anomalycanbeinterpretedasdiscontinuities E= + B 6(d~dm)]~ ~O —al/n (2)of critical amplitude.Thepurposeof this letter is toclarify the situationby consideringtheleadingloga-rithmic termsup to the orderof 1/n3. (_B)rn 1
Wehavederivedthe expressionfor the in Z(Z: 2(1—d)~(d,dm)e ~° +
partition function)up to theorderof i/n3. On thewith
basisof this expression,we havecalculatedthelead-inglogarithmic termsup to theorderof(ln e)3/n3, a
1 = &~=~ ‘y~(~—d).e beingdefinedby e = Kc — K. It turnsoutthat theenergyin a reducedform is expressedas Fromeq.(2) wecanseethat the result [2—4]without
1 ~ anomaloustermis restored,so that a1 is continuousE~~e~00—-{&i +.}7i(_B)rn~(d,drn)} e °ln� at d = dm. However,the critical amplitude:
[1+ (_B)m6(d,dm)/2 (1 — d)] doesnotjoint continu-1-—~---{&~+~~ (_B)m~(d,drn)}&ie
1~°(lne)2 ously to its valueat n = °° in thecaseofd = drn, and2n2 thereforethecritical amplitude showsdiscontinuities
1 {&i ÷~~ _BY~~id,dm)}&? e’~0(lne)3 at d = dmwhen it is regardedasa function of d.
3!n3 The abovesituationmaybestatedin the following
(1) way. Forthe unperturbedsystem(n = oo), E is ex-pressedasE= e’~0. In the presenceof perturbation,
where however,this termis split off into two partsas shown
= 7~(1 —d), in eq.(2) at d = drn. In this sence,the anomalouscaseis supposedto correspondto thedegenerateunper-
( By~=4 {mr [(1/2)+(1/m)]lm turbedstate.— r’(I/2)r(1/rn) j ford 2+2/rn, It is alsoexpectedthat the anomalousbehaviorof
= 0 for d*2+2/m. afor the long-rangeinteraction[1,5] is interpretedin a similarway. Details of this articlewill be publish-
If oneassumesa simplepowerlawinz = �2_an_al “i edelsewhere.
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Volume45A, number1 PHYSICS LETTERS 27 AugUst 1973
It is ourpleasure-toexpressoursincerethanksto ReferencesProfessorsK.G. Wilson andF. Wegnerfor giving usvaluablecommentsandto ProfressorS. Ma for send- [1] R. AbeandS. Hikami, Phys.Lett.42A (1973)419,
ing us papersprior to publication. Frog. Theor.Phys.49 (1973)No. 6.[2] R. AbeandS.Hikami, Prog.Theor.Phys.49 (1973)442.3] S. Ma, Universityof California preprint.
[4] R.A. FerrellandD.J. Scalapino,Phys.Lett. 41A (1972)371.
[5] M. Suzuki,Frog.Theor.Phys.49 (1973)424.
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