Noncommutative and Ordinary Super Yang-Mills on (D$(p-2)$, D$p$) Bound States

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The Subleading Isgur-Wise Form Factor $chi_3(vcdot v')$ to Order $alpha_s$ in QCD Sum Rules

The Subleading Isgur-Wise Form Factor $chi_3(vcdot v')$ to Order $alpha_s$ in QCD Sum Rules

a rXiv:h ep-ph/9212266v116Dec1992SLAC–PUB–6017WIS–92/99/Dec–PH December 1992T/E The Subleading Isgur-Wise Form Factor χ3(v ·v ′)to Order αs in QCD Sum Rules Matthias Neubert Stanford Linear Accelerator Center Stanford University,Stanford,California 94309Zoltan Ligeti and Yosef Nir Weizmann Institute of Science Physics Department,Rehovot 76100,Israel We calculate the contributions arising at order αs in the QCD sum rule for the spin-symmetry violating universal function χ3(v ·v ′),which appears at order 1/m Q in the heavy quark expansion of meson form factors.In particular,we derive the two-loop perturbative contribution to the sum rule.Over the kinematic range accessible in B →D (∗)ℓνdecays,we find that χ3(v ·v ′)does not exceed the level of ∼1%,indicating that power corrections induced by the chromo-magnetic operator in the heavy quark expansion are small.(submitted to Physical Review D)I.INTRODUCTIONIn the heavy quark effective theory(HQET),the hadronic matrix elements describing the semileptonic decays M(v)→M′(v′)ℓν,where M and M′are pseudoscalar or vector mesons containing a heavy quark,can be systematically expanded in inverse powers of the heavy quark masses[1–5].The coefficients in this expansion are m Q-independent,universal functions of the kinematic variable y=v·v′.These so-called Isgur-Wise form factors characterize the properties of the cloud of light quarks and gluons surrounding the heavy quarks,which act as static color sources.At leading order,a single functionξ(y)suffices to parameterize all matrix elements[6].This is expressed in the compact trace formula[5,7] M′(v′)|J(0)|M(v) =−ξ(y)tr{(2)m M P+ −γ5;pseudoscalar meson/ǫ;vector mesonis a spin wave function that describes correctly the transformation properties(under boosts and heavy quark spin rotations)of the meson states in the effective theory.P+=1g s2m Q O mag,O mag=M′(v′)ΓP+iσαβM(v) .(4)The mass parameter¯Λsets the canonical scale for power corrections in HQET.In the m Q→∞limit,it measures thefinite mass difference between a heavy meson and the heavy quark that it contains[11].By factoring out this parameter,χαβ(v,v′)becomes dimensionless.The most general decomposition of this form factor involves two real,scalar functionsχ2(y)andχ3(y)defined by[10]χαβ(v,v′)=(v′αγβ−v′βγα)χ2(y)−2iσαβχ3(y).(5)Irrespective of the structure of the current J ,the form factor χ3(y )appears always in the following combination with ξ(y ):ξ(y )+2Z ¯Λ d M m Q ′ χ3(y ),(6)where d P =3for a pseudoscalar and d V =−1for a vector meson.It thus effectively renormalizes the leading Isgur-Wise function,preserving its normalization at y =1since χ3(1)=0according to Luke’s theorem [10].Eq.(6)shows that knowledge of χ3(y )is needed if one wants to relate processes which are connected by the spin symmetry,such as B →D ℓνand B →D ∗ℓν.Being hadronic form factors,the universal functions in HQET can only be investigated using nonperturbative methods.QCD sum rules have become very popular for this purpose.They have been reformulated in the context of the effective theory and have been applied to the study of meson decay constants and the Isgur-Wise functions both in leading and next-to-leading order in the 1/m Q expansion [12–21].In particular,it has been shown that very simple predictions for the spin-symmetry violating form factors are obtained when terms of order αs are neglected,namely [17]χ2(y )=0,χ3(y )∝ ¯q g s σαβG αβq [1−ξ(y )].(7)In this approach χ3(y )is proportional to the mixed quark-gluon condensate,and it was estimated that χ3(y )∼1%for large recoil (y ∼1.5).In a recent work we have refined the prediction for χ2(y )by including contributions of order αs in the sum rule analysis [20].We found that these are as important as the contribution of the mixed condensate in (7).It is,therefore,worthwhile to include such effects also in the analysis of χ3(y ).This is the purpose of this article.II.DERIV ATION OF THE SUM RULEThe QCD sum rule analysis of the functions χ2(y )and χ3(y )is very similar.We shall,therefore,only briefly sketch the general procedure and refer for details to Refs.[17,20].Our starting point is the correlatord x d x ′d ze i (k ′·x ′−k ·x ) 0|T[¯q ΓM ′P ′+ΓP +iσαβP +ΓM+Ξ3(ω,ω′,y )tr 2σαβ2(1+/v ′),and we omit the velocity labels in h and h ′for simplicity.The heavy-light currents interpolate pseudoscalar or vector mesons,depending on the choice ΓM =−γ5or ΓM =γµ−v µ,respectively.The external momenta k and k ′in (8)are the “residual”off-shell momenta of the heavy quarks.Due to the phase redefinition of the effective heavy quark fields in HQET,they are related to the total momenta P and P ′by k =P −m Q v and k ′=P ′−m Q ′v ′[3].The coefficient functions Ξi are analytic in ω=2v ·k and ω′=2v ′·k ′,with discontinuities for positive values of these variables.They can be saturated by intermediate states which couple to the heavy-light currents.In particular,there is a double-pole contribution from the ground-state mesons M and M ′.To leading order in the 1/m Q expansion the pole position is at ω=ω′=2¯Λ.In the case of Ξ2,the residue of the pole is proportional to the universal function χ2(y ).For Ξ3the situation is more complicated,however,since insertions of the chromo-magnetic operator not only renormalize the leading Isgur-Wise function,but also the coupling of the heavy mesons to the interpolating heavy-light currents (i.e.,the meson decay constants)and the physical meson masses,which define the position of the pole.1The correct expression for the pole contribution to Ξ3is [17]Ξpole 3(ω,ω′,y )=F 2(ω−2¯Λ+iǫ) .(9)Here F is the analog of the meson decay constant in the effective theory (F ∼f M√m QδΛ2+... , 0|j (0)|M (v ) =iF2G 2tr 2σαβΓP +σαβM (v ) ,where the ellipses represent spin-symmetry conserving or higher order power corrections,and j =¯q Γh (v ).In terms of the vector–pseudoscalar mass splitting,the parameter δΛ2isgiven by m 2V −m 2P =−8¯ΛδΛ2.For not too small,negative values of ωand ω′,the coefficient function Ξ3can be approx-imated as a perturbative series in αs ,supplemented by the leading power corrections in 1/ωand 1/ω′,which are proportional to vacuum expectation values of local quark-gluon opera-tors,the so-called condensates [22].This is how nonperturbative corrections are incorporated in this approach.The idea of QCD sum rules is to match this theoretical representation of Ξ3to the phenomenological pole contribution given in (9).To this end,one first writes the theoretical expression in terms of a double dispersion integral,Ξth 3(ω,ω′,y )= d νd ν′ρth 3(ν,ν′,y )1Thereare no such additional terms for Ξ2because of the peculiar trace structure associated with this coefficient function.possible subtraction terms.Because of theflavor symmetry it is natural to set the Borel parameters associated withωandω′equal:τ=τ′=2T.One then introduces new variables ω±=12T ξ(y) F2e−2¯Λ/T=ω0dω+e−ω+/T ρth3(ω+,y)≡K(T,ω0,y).(12)The effective spectral density ρth3arises after integration of the double spectral density over ω−.Note that for each contribution to it the dependence onω+is known on dimensionalgrounds.It thus suffices to calculate directly the Borel transform of the individual con-tributions toΞth3,corresponding to the limitω0→∞in(12).Theω0-dependence can be recovered at the end of the calculation.When terms of orderαs are neglected,contributions to the sum rule forΞ3can only be proportional to condensates involving the gluonfield,since there is no way to contract the gluon contained in O mag.The leading power correction of this type is represented by the diagram shown in Fig.1(d).It is proportional to the mixed quark-gluon condensate and,as shown in Ref.[17],leads to(7).Here we are interested in the additional contributions arising at orderαs.They are shown in Fig.1(a)-(c).Besides a two-loop perturbative contribution, one encounters further nonperturbative corrections proportional to the quark and the gluon condensate.Let usfirst present the result for the nonperturbative power corrections.WefindK cond(T,ω0,y)=αs ¯q q TT + αs GG y+1− ¯q g sσαβGαβq√y2−1),δn(x)=1(4π)D×1dλλ1−D∞λd u1∞1/λd u2(u1u2−1)D/2−2where C F=(N2c−1)/2N c,and D is the dimension of space-time.For D=4,the integrand diverges asλ→0.To regulate the integral,we assume D<2and use a triple integration by parts inλto obtain an expression which can be analytically continued to the vicinity of D=4.Next we set D=4+2ǫ,expand inǫ,write the result as an integral overω+,and introduce back the continuum threshold.This givesK pert(T,ω0,y)=−αsy+1 2ω0dω+ω3+e−ω+/T(16)× 12−23∂µ+3αs9π¯Λ,(17)which shows that divergences arise at orderαs.At this order,the renormalization of the sum rule is thus accomplished by a renormalization of the“bare”parameter G2in(12).In the9π¯Λ 1µ2 +O(g3s).(18)Hence a counterterm proportional to¯Λξ(y)has to be added to the bracket on the left-hand side of the sum rule(12).To evaluate its effect on the right-hand side,we note that in D dimensions[17]¯Λξ(y)F2e−2¯Λ/T=3y+1 2ω0dω+ω3+e−ω+/T(19)× 1+ǫ γE−ln4π+2lnω+−ln y+12T ξ(y) F2e−2¯Λ/T=αsy+1 2ω0dω+ω3+e−ω+/T 2lnµ6+ y r(y)−1+ln y+1According to Luke’stheorem,theuniversalfunction χ3(y )vanishes at zero recoil [10].Evaluating (20)for y =1,we thus obtain a sum rule for G 2(µ)and δΛ2.It reads G 2(µ)−¯ΛδΛ224π3ω00d ω+ω3+e −ω+/T ln µ12 +K cond (T,ω0,1),(21)where we have used that r (1)=1.Precisely this sum rule has been derived previously,starting from a two-current correlator,in Ref.[16].This provides a nontrivial check of our ing the fact that ξ(y )=[2/(y +1)]2+O (g s )according to (19),we find that the µ-dependent terms cancel out when we eliminate G 2(µ)and δΛ2from the sum rule for χ3(y ).Before we present our final result,there is one more effect which has to be taken into account,namely a spin-symmetry violating correction to the continuum threshold ω0.Since the chromo-magnetic interaction changes the masses of the ground-state mesons [cf.(10)],it also changes the masses of higher resonance states.Expanding the physical threshold asωphys =ω0 1+d M8π3 22 δ3 ω032π2ω30e −ω0/T 26π2−r (y )−ξ(y ) δ0 ω096π 248T 1−ξ(y ).It explicitly exhibits the fact that χ3(1)=0.III.NUMERICAL ANALYSISLet us now turn to the evaluation of the sum rule (23).For the QCD parameters we take the standard values¯q q =−(0.23GeV)3,αs GG =0.04GeV4,¯q g sσαβGαβq =m20 ¯q q ,m20=0.8GeV2.(24) Furthermore,we useδω2=−0.1GeV from above,andαs/π=0.1corresponding to the scale µ=2¯Λ≃1GeV,which is appropriate for evaluating radiative corrections in the effective theory[15].The sensitivity of our results to changes in these parameters will be discussed below.The dependence of the left-hand side of(23)on¯Λand F can be eliminated by using a QCD sum rule for these parameters,too.It reads[16]¯ΛF2e−2¯Λ/T=9T4T − ¯q g sσαβGαβq4π2 2T − ¯q q +(2y+1)4T2.(26) Combining(23),(25)and(26),we obtainχ3(y)as a function ofω0and T.These parameters can be determined from the analysis of a QCD sum rule for the correlator of two heavy-light currents in the effective theory[16,18].Onefinds good stability forω0=2.0±0.3GeV,and the consistency of the theoretical calculation requires that the Borel parameter be in the range0.6<T<1.0GeV.It supports the self-consistency of the approach that,as shown in Fig.2,wefind stability of the sum rule(23)in the same region of parameter space.Note that it is in fact theδω2-term that stabilizes the sum rule.Without it there were no plateau.Over the kinematic range accessible in semileptonic B→D(∗)ℓνdecays,we show in Fig.3(a)the range of predictions forχ3(y)obtained for1.7<ω0<2.3GeV and0.7<T< 1.2GeV.From this we estimate a relative uncertainty of∼±25%,which is mainly due to the uncertainty in the continuum threshold.It is apparent that the form factor is small,not exceeding the level of1%.2Finally,we show in Fig.3(b)the contributions of the individual terms in the sum rule (23).Due to the large negative contribution proportional to the quark condensate,the terms of orderαs,which we have calculated in this paper,cancel each other to a large extent.As a consequence,ourfinal result forχ3(y)is not very different from that obtained neglecting these terms[17].This is,however,an accident.For instance,the order-αs corrections would enhance the sum rule prediction by a factor of two if the ¯q q -term had the opposite sign. From thisfigure one can also deduce how changes in the values of the vacuum condensates would affect the numerical results.As long as one stays within the standard limits,the sensitivity to such changes is in fact rather small.For instance,working with the larger value ¯q q =−(0.26GeV)3,or varying m20between0.6and1.0GeV2,changesχ3(y)by no more than±0.15%.In conclusion,we have presented the complete order-αs QCD sum rule analysis of the subleading Isgur-Wise functionχ3(y),including in particular the two-loop perturbative con-tribution.Wefind that over the kinematic region accessible in semileptonic B decays this form factor is small,typically of the order of1%.When combined with our previous analysis [20],which predicted similarly small values for the universal functionχ2(y),these results strongly indicate that power corrections in the heavy quark expansion which are induced by the chromo-magnetic interaction between the gluonfield and the heavy quark spin are small.ACKNOWLEDGMENTSIt is a pleasure to thank Michael Peskin for helpful discussions.M.N.gratefully acknowl-edgesfinancial support from the BASF Aktiengesellschaft and from the German National Scholarship Foundation.Y.N.is an incumbent of the Ruth E.Recu Career Development chair,and is supported in part by the Israel Commission for Basic Research and by the Minerva Foundation.This work was also supported by the Department of Energy,contract DE-AC03-76SF00515.REFERENCES[1]E.Eichten and B.Hill,Phys.Lett.B234,511(1990);243,427(1990).[2]B.Grinstein,Nucl.Phys.B339,253(1990).[3]H.Georgi,Phys.Lett.B240,447(1990).[4]T.Mannel,W.Roberts and Z.Ryzak,Nucl.Phys.B368,204(1992).[5]A.F.Falk,H.Georgi,B.Grinstein,and M.B.Wise,Nucl.Phys.B343,1(1990).[6]N.Isgur and M.B.Wise,Phys.Lett.B232,113(1989);237,527(1990).[7]J.D.Bjorken,Proceedings of the18th SLAC Summer Institute on Particle Physics,pp.167,Stanford,California,July1990,edited by J.F.Hawthorne(SLAC,Stanford,1991).[8]M.B.Voloshin and M.A.Shifman,Yad.Fiz.45,463(1987)[Sov.J.Nucl.Phys.45,292(1987)];47,801(1988)[47,511(1988)].[9]A.F.Falk,B.Grinstein,and M.E.Luke,Nucl.Phys.B357,185(1991).[10]M.E.Luke,Phys.Lett.B252,447(1990).[11]A.F.Falk,M.Neubert,and M.E.Luke,SLAC preprint SLAC–PUB–5771(1992),toappear in Nucl.Phys.B.[12]M.Neubert,V.Rieckert,B.Stech,and Q.P.Xu,in Heavy Flavours,edited by A.J.Buras and M.Lindner,Advanced Series on Directions in High Energy Physics(World Scientific,Singapore,1992).[13]A.V.Radyushkin,Phys.Lett.B271,218(1991).[14]D.J.Broadhurst and A.G.Grozin,Phys.Lett.B274,421(1992).[15]M.Neubert,Phys.Rev.D45,2451(1992).[16]M.Neubert,Phys.Rev.D46,1076(1992).[17]M.Neubert,Phys.Rev.D46,3914(1992).[18]E.Bagan,P.Ball,V.M.Braun,and H.G.Dosch,Phys.Lett.B278,457(1992);E.Bagan,P.Ball,and P.Gosdzinsky,Heidelberg preprint HD–THEP–92–40(1992).[19]B.Blok and M.Shifman,Santa Barbara preprint NSF–ITP–92–100(1992).[20]M.Neubert,Z.Ligeti,and Y.Nir,SLAC preprint SLAC–PUB–5915(1992).[21]M.Neubert,SLAC preprint SLAC–PUB–5992(1992).[22]M.A.Shifman,A.I.Vainshtein,and V.I.Zakharov,Nucl.Phys.B147,385(1979);B147,448(1979).FIGURESFIG.1.Diagrams contributing to the sum rule for the universal form factorχ3(v·v′):two-loop perturbative contribution(a),and nonperturbative contributions proportional to the quark con-densate(b),the gluon condensate(c),and the mixed condensate(d).Heavy quark propagators are drawn as double lines.The square represents the chromo-magnetic operator.FIG.2.Analysis of the stability region for the sum rule(23):The form factorχ3(y)is shown for y=1.5as a function of the Borel parameter.From top to bottom,the solid curves refer toω0=1.7,2.0,and2.3GeV.The dashes lines are obtained by neglecting the contribution proportional toδω2.FIG.3.(a)Prediction for the form factorχ3(v·v′)in the stability region1.7<ω0<2.3 GeV and0.7<T<1.2GeV.(b)Individual contributions toχ3(v·v′)for T=0.8GeV and ω0=2.0GeV:total(solid),mixed condensate(dashed-dotted),gluon condensate(wide dots), quark condensate(dashes).The perturbative contribution and theδω2-term are indistinguishable in thisfigure and are both represented by the narrow dots.11。

群论第8章

群论第8章
H (五维表示),", 一维复共轭表示实际上是二维表示(Mulliken 记号),物理上是不可约的。
能级简并(时间反演的结果). 实表示:Cn 的特征标为+1( A 表示),-1( B 表示)。 反演对称操作i 的特征标为 1(偶宇称,下标用 g ),-1(奇宇称,下标用u ).
除Ci ,有 10 个点群具有反演操作i 对称,它们均可以表示为Ci 群与另一正 则转动群的直积:
对 n = 2,4,6 ,它包含一个反演操作 I (≡ C2σ h )。
Sn 群:有一个 n 度转动反演轴( n = 4,6 ); 对 n = 2,3的 S2 和 S3 ,一般用 Ci 和 C3h 符号;
Dn 群:有一个 n 度转动轴及 n 个与之垂直的二度轴( n = 2,3,4,6 ); Dnd 群: Dn 群加 4 n 个垂直对交镜面( n = 2,3)镜面将二度轴角度平分。 Dnh 群: Dn 群加一个水平镜面( n = 2,3,4,6 ). n = 2,4,6 时, Dnh 包含反演操作。 除以上 27 个群外,还有Oh , O ,Td ,Th 和T 群。
群 论 讲 稿----吴 长 勤
第八章 点群和空间群 (Point Groups and Space Groups)
§1 点群 (Point Groups)
点群:使系统(如分子)不变的对称操作的集合构成的群。(某点固定,空 间任何两点距离不变的有限群)
一般,几何对称操作有:
E : 恒等操作;
Cn :转角 2π / n 的操作,转动轴称 n 度轴;
{ } C3v : {E}, C3,C32 , {σ1,σ 2 ,σ 3}; 三个共轭类。 { } { } C'3v : {E},{E}, C3,C32 , EC3, EC32 ,{σ1,σ 2 ,σ 3},{Eσ1, Eσ 2 , Eσ 3};

双指标非交换鞅的一些不等式

双指标非交换鞅的一些不等式

双指标非交换鞅的一些不等式尹磾;马聪变【摘要】In this paper, we discuss the inequalities of two-parameter noncommutative martingales. By using the inequalities of one-parameter noncommutative martingales methods, we obtain the relation betweenk · kHp(M) and k · khp(M) of two-parameter noncommutative martingales (2 ≤ p < ∞), which generalize the equivalence relation between k · kLp(M) and k · khp(M) of two-parameter noncommutative martingales (2≤p≤4) .%本文研究了双指标非交换鞅的一些不等式问题.利用单指标非交换鞅不等式的方法,获得了双指标非交换鞅的k·kHp(M)和k·khp(M)之间的关系(2≤p<∞).推广了双指标非交换鞅的k·kLp(M)和k·khp(M)之间的等价关系(2≤p≤4).【期刊名称】《数学杂志》【年(卷),期】2017(037)004【总页数】8页(P851-858)【关键词】von Neumann代数;双指标鞅;Burkholder不等式;鞅 Hardy空间【作者】尹磾;马聪变【作者单位】武汉大学数学与统计学院,湖北武汉 430072;武汉大学数学与统计学院,湖北武汉 430072【正文语种】中文【中图分类】O177.5非交换鞅空间理论是非交换数学中分析理论的有机组成部分,是当前泛函分析领域的前沿研究方向.从20世纪70年代,人们开始研究非交换鞅.为了研究非交换鞅空间,需要引进新的思想和方法.1971年Cuculescu[1]研究了非交换鞅的弱(1,1)型不等式并提出了著名Cuculescu构造以取代停时的方法.1997年Pisier和Xu[2]取得重大突破,他通过引进列均方函数与行均方函数对p<2与p≥2分别定义了恰当的非交换鞅的Hardy空间Hp(M),并由此证明Burkholder-Gundy鞅不等式的非交换类比.随后经过众多数学家的努力,非交换鞅取得重要进展.到目前为止,绝大多数经典鞅的不等式都成功过渡到了非交换情形,例如条件均方函数的Burkholder不等式[3],Doob极大不等式[4],Stein不等式[2]等.双指标鞅是单指标鞅的自然推广.在交换的情形,Weisz对双指标鞅做了许多工作(见文[5]).Weisz的工作表明,从单指标到双指标绝不是简单的推广,实际上很多在单指标鞅研究中常用的方法不能够适用于双指标鞅的情形.因此常常需要一些新的技巧和方法.关于双指标非交换鞅的研究目前尚属起步阶段.本文研究双指标非交换鞅,证明了双指标非交换鞅的一些不等式.包括双指标非交换鞅的‖·‖Hp(M)和‖·‖hp(M)之间的关系,双指标非交换序列的Stein不等式以及‖·‖Lp(M)和‖·‖hp(M)之间的等价关系. 首先回顾一下关于非交换Lp-空间的一些基本定义与记号.设(M,τ)是一个非交换概率空间,这里M是Hilbert空间H上的von Neumann代数,τ为M上的正规忠实的迹,满足τ(1)=1.记L0(M)为关于(M,τ)的可测算子全体组成的拓扑∗-代数.设1≤p <∞,令其中表示x的模.定义则(Lp(M),‖·‖p)是Banach空间,称之为关于(M,τ)的非交换Lp-空间.当p=∞时,规定L∞(M)=M,且L∞(M)上的范数‖·‖∞为算子范数.设(Mn)n≥0是M的一列单调增加的子von Neumann代数,用En表示M到Mn的条件期望算子.Lp(M)中的序列x=(xn)n≥0称为是关于(Mn)n≥0的鞅,若对任意的m≥n,有En(xm)=xn.关于非交换Lp-空间与非交换鞅的更详细的介绍可参见文献[6].设N是非负整数的集合,N2={ (n1,n2):n1,n2∈N}.在N2上定义半序如下:对任意的n=(n1,n2),m=(m1,m2)∈N2,定义n≤m当且仅当n1≤m1,n2≤m2以及n<m若n≤m且n/m.设(Mn;n∈N2)是M的一列关于N2偏序单调增加的子von Neumann代数,并且在M中w∗-稠密.对任意的n=(n1,n2)∈N2,用En或者En1,n2表示M到Mn的条件期望算子.一般地,对于M的任意一列子von Neumann代数(Nn;n≥0),令表示包含的最小的von Neumann代数.对每个(n1,n2)∈N2,定义以后总是设(Mn;n∈N2)满足(F4)条件:对任意的x∈M和任意的n=(n1,n2)∈N2,有为了方便起见,规定对任意的x∈L1(M),当n1=0或者n2=0时,En1,n2(x)=0.定义2.1 设x=(xn,n∈N2)是L1(M)中的序列.称x为关于(Mn)n∈N2的鞅,如果满足若进一步对每个n∈N2,有xn∈Lp(M)(1≤p≤∞),则称x为关于(Mn)n∈N2的Lp-鞅.此时,令若‖x‖p<∞,则称x为Lp-有界鞅.设x=(xn,n∈N2)是关于(Mn)n∈N2的鞅,n=(n1,n2).令约定当n1=0或者n2=0时,dxn=0,称dx=(dxn)为x的鞅差序列.容易证明当(Mn)n∈N2满足(F4)条件时,若(dxn,n∈N2)是鞅差序列,则En(dxm)=0(∀nm). 为了定义关于双指标非交换鞅的Hardy空间,先回顾一下非交换列空间与行空间的定义(详见文[6]).设1≤p<∞,x=(xn)是Lp(M)中的有限序列.令则‖·‖Lp(M,lc2)和‖·‖Lp(M,lr2)在Lp(M)的有限序列上定义了范数.相应的完备化空间分别记为.注意到对于Lp(M)中的一个序列(xn),如果在Lp(M)中有界,则极限存在.用表示这个极限,则当1≤p<∞时,CRp[Lp(M)]空间定义如下.(i)当p≥2时,定义,赋予范数(ii)当1≤p<2时,定义,赋予范数下面定义双指标非交换鞅的Hardy空间Hp(M).设x=(xn,n∈N2)是一个鞅,令如果(Sc,(n,n)(x))n≥1和(Sr,(n,n)(x))n≥1在Lp(M)中有界,令称Sc(x)和Sr(x)分别为鞅x=(xn,n∈N2)的列均方函数与行均方函数.定义2.2 (i)设1≤p<∞.定义双指标非交换鞅的列Hardy空间,类似地,定义双指标非交换鞅的行Hardy空间.(ii)定义非交换鞅Hardy空间如下.当1≤p≤2时,定义,赋予范数当2≤p<∞时,定义,赋予范数注对一个双指标鞅x=(xn,n∈N2)的鞅差序列dx=(dxn)n∈N2,把它重新编号变成一个单指标的序列,则可以把它视为一个单指标序列dx=(xn)(但是要注意的是xn)一般不是单指标的鞅差序列).因此,无论x=(xn)是单指标鞅还是双指标鞅都有下面定义双指标非交换鞅Hardy空间hp(M).由于这里需要考虑双指标有限鞅,为此先给出双指标有限鞅的知识.设x=(xn,n∈N2)是一个鞅,k∈N,称形如x(k)=(xn1∧k,n2∧k,(n1,n2)∈N2)为停止于k的有限鞅.设1≤p<∞,对Lp(M)中的有限鞅x=(xn),定义记分别为按上述范数完备化的Banach空间.对L2(M)中任意的有限鞅x=(xn),令则‖x‖hcp(M)=‖sc(x)‖p,‖x‖hrp(M)=‖sr(x)‖p.还需要考虑lp(Lp(M)),定义记为lp(Lp(M))中由所有鞅差序列构成的子空间,并且定义‖x‖hdp(M)=‖dx‖lp(Lp(M)).定义2.3 (i)设1≤p<2.定义,赋予范数(ii)设2≤p<∞.定义,赋予范数在这一部分研究双指标非交换鞅Hardy空间的一些不等式,包括双指标非交换鞅的‖·‖Hp(M)和‖·‖hp(M)之间的关系,双指标非交换序列的Stein不等式以及‖·‖Lp(M)和‖·‖hp(M)之间的等价关系.这些结果是关于单指标鞅相应的结果在双指标鞅相应的推广(见文[3]).下面的定理3.1是这一节的主要结果.定理3.1 设x=(xn)n∈N2是Lp(M)中的鞅.则(i) 当1≤p≤2 时,有‖x‖Hp(M)≤Cp‖x‖hp(M);(ii)当2≤p<∞ 时,有‖x‖hp(M)≤p‖x‖Hp(M),其中Cp和p是只依赖于p的常数. 为证明上述定理,需要用到下面的一系列引理.引理3.2[3,4]设(Mn)n≥1是M的一列单调递增的子von Neumann代数,En表示M到Mn的条件期望算子.则对任意的有限序列,有这里Cp是只依赖于p的正常数.下面把引理3.2推广到双指标的情形.引理3.3 设(Mn)n∈N2是M的一列关于N2偏序单调递增的子von Neumann 代数,En表示M到Mn的条件期望算子,则对任意的有限双指标序列,有这里Cp与引理3.2中的Cp一致.证 (i)利用(F4)条件和引理3.2,有(ii)证明方法与(i)的证明是类似的.证毕.推论3.4 (双指标序列的Stein不等式)设2≤p<∞,则对Lp(M)中任意的有限双指标序列(an),有这里Cp与引理3.3中的Cp一致.证利用引理3.3和不等式E(x)∗E(x)≤E(|x|2),得到定理证毕.引理3.5 设1≤p<∞.则对任意的有限双指标序列(xn)⊂Lp(M),有(i)当2≤p<∞时,(ii)当1≤p≤2时,证(i)将(xn)n∈N2进行重新编号为一个单指标的序列,再利用非交换单指标的结论(见文[7]),就得到所要证明的不等式.(ii)证明方法与(i)的证明是类似的.引理证毕.定理3.1的证明(i)先考虑有限鞅的情形.设x=(xn)为hp(M)中停止于k的有限鞅.设x=y+z+w是x的一个分解,其中y,z分别为中的有限鞅,,满足dwk=0,∀k(n,n).由于,由引理3.3(i),有类似地,可以证明接下来证明由定义知道利用引理3.5(ii),得到令,则对x的所有分解取下确界,得到‖x‖Hp(M)≤Cp‖x‖hp(M).一般情形,设x=(xn)n∈N2∈hp(M).对任意的k∈N,令x(k)=(xn1∧k,n2∧k)n∈N2.由上面证明得到‖x(k)‖Hp(M)≤Cp‖x(k)‖hp(M).再令k→∞得到‖x‖Hp(M)≤Cp‖x‖hp(M).(ii)与(i)的证明类似,也先考虑有限鞅的情形.设x=(xn)为Hp(M)中停止于k的有限鞅.由引理3.3(ii)得到通过取伴随得到其次证明由引理 3.5(i) 得到令,由上面的证明得到一般情形,先考虑有限鞅,再取极限即得到所要的结论.定理证毕.下面转到双指标非交换鞅的Burkholder不等式.要用到下面的双指标非交换鞅的Burkholder-Gundy不等式.引理3.6 [7]设1<p<∞.x=(xn,n∈N2)是Lp(M)中的鞅,则x是Lp-有界鞅当且仅当x∈Hp(M).更确切地说,有这里的αp,βp是只与p有关的正常数.定理3.7 设2≤p≤4,x=(xn,n∈N2)是Lp(M)中的鞅,则x是Lp-有界鞅当且仅当x∈hp(M).更确切地说,有这里的αp,βp为引理3.6中的常数,为定理3.1(ii)中的常数.证首先证明第一个不等式.事实上,由定理3.1(ii)和引理3.6可知接下来证明第二个不等式.由引理3.6知‖x‖p≤βp‖x‖Hp(M).下面只需再证明不妨设‖x‖hp(M)≤1.有令|dxn|2=En-1|dxn|2+dyn(n∈N2),这里dyn=|dxn|2-En-1|dxn|2.注意到,有这里y是一个鞅.注意到,利用引理3.5(ii)和引理3.6,得到因此通过取伴随可证因此定理证毕.由定理3.7和定理3.1(ii)得到如下推论.推论3.8 设2≤p≤4,对任意的Lp-有限鞅x=(xn,n∈N2),有证第二个不等式直接由定理3.1得到.对于第一个不等式,由引理3.6和定理3.7得到.证毕.【相关文献】[1]Cuculescu I.Martingales on von Neumann algebras[J].J.Multi.Anal.,1971,1:17-27.[2]Pisier G,Xu Quanhua.Non-commutative martingaleinequalities[J].Comm.Math.Phys.,1997,189:667-698.[3]Junge M,Xu Q.Noncommutative Burkholder/Rosenthal inequalities[J].Ann.Prob.,2003,31:948-995.[4]Junge M.Doob’s inequalities for non-commutative martingales[J].J.ReineAngew.Math.,2002,549:149-190.[5]Weisz F.Martingale Hardy spaces and their application in Fourier analysis[M].Berlin:Springer-Verlag.1994.[6]Pisier G,Xu Quanhua.Non-commutativeLp-spaces[M].Vol.II,Holland:Elsevier,2003.[7]曹芳.双指标非交换鞅的收敛性和不等式[J].数学杂志,2015,35(6):1511-1520.。

21925065_榴辉岩中单斜辉石-石榴子石镁同位素地质温度计评述

21925065_榴辉岩中单斜辉石-石榴子石镁同位素地质温度计评述

1000 0569/2020/036(06) 1705 18ActaPetrologicaSinica 岩石学报doi:10 18654/1000 0569/2020 06 04榴辉岩中单斜辉石 石榴子石镁同位素地质温度计评述黄宏炜1 杜瑾雪1 柯珊2HUANGHongWei1,DUJinXue1 andKEShan21 中国地质大学地球科学与资源学院,北京 1000832 中国地质大学地质过程与矿产资源国家重点实验室,北京 1000831 SchoolofEarthSciencesandResources,ChinaUniversityofGeosciences,Beijing100083,China2 StateKeyLaboratoryofGeologicalProcessesandMineralResources,ChinaUniversityofGeosciences,Beijing100083,China2019 11 14收稿,2020 04 08改回HuangHW,DuJXandKeS 2020 Reviewontheclinopyroxene garnetmagnesiumisotopegeothermometersforeclogites ActaPetrologicaSinica,36(6):1705-1718,doi:10 18654/1000 0569/2020 06 04Abstract Theremarkableequilibriummagnesiumisotopefractionationbetweenclinopyroxeneandgarnetobservedineclogitesmakesitapotentialhigh precisiongeothermometer Therefore,thispaperselects64pairsofclinopyroxene garnetmagnesiumisotopedataofeclogitesintheChinesesouthwesternTianshanorogen,intheDabie SuluorogenandintheKaapvaalcratonintheSouthAfricafromliteratures Then,wescreened50pairsofdatathatreachtheequilibriummagnesiumisotopefractionationbytheδ26MgCpx δ26MgGrtdiagram Usingthesemagnesiumisotopeequilibriumfractionationdata,wecalculatedpeaktemperaturesofeclogitesbymagnesiumisotopegeothermometersofHuangetal (2013)throughfirst principlescalculationandWangetal (2012)andLietal (2016)throughempiricalestimation,andcomparedthemwiththepeaktemperaturesgivenbyothergeothermometers Byanalyzingthecalculationresults,itisfoundthatfororogeniceclogites,thecalculationresultsofthegeothermometerofHuangetal (2013)areconsistentwiththosepreviouslyobtainedbytraditionalgeothermometersandphaseequilibriamodeling,whilethecalculationresultsofthegeothermometersofWangetal (2012)andLietal (2016)aresignificantlylower Forthecratoneclogites,thecalculationresultsofallthethreemagnesiumisotopegeothermometersaresignificantlydifferentfromresultsoftraditionalgeothermometersbymorethan50℃,whichismostprobablycausedbyre equilibriumofmagnesiumisotopeduringearlyretrogrademetamorphismathightemperatures Thisindicatesthatthesethreemagnesiumisotopegeothermometersarenotapplicableforthecratoneclogites Basedontheabovedata,themethodofempiricalestimationisusedtocalibrateanewclinopyroxene garnetmagnesiumisotopegeothermometer,whichisΔ26MgCpx Grt=1 11×106/[T(K)]2(R2=0 92).Inaddition,thispaperalsobrieflydiscussesapplicationprospectoftheclinopyroxene garnetmagnesiumisotopegeothermometersandtheproblemsthatshouldbepaidattentiontoduringapplication Keywords Eclogites;Isotopegeothermometer;Magnesiumisotope;Clinopyroxene garnet摘 要 榴辉岩中单斜辉石和石榴子石之间显著的镁同位素平衡分馏,使其成为一种具有潜力的高精度地质温度计。

QCD Sum Rules - a Working Tool for Hadronic Physics

QCD Sum Rules - a Working Tool for Hadronic Physics
QCD sum rules are overviewed with an emphasize on the practical applications of this method to the physics of light and heavy hadrons.
talk given at Continuous Advances in QCD 2002/ ARKADYFEST (honoring the 60th birthday of Arkady Vainshtein), Minneapolis, Minnesota, 17-23 May 2002.
TTP02-23
arXiv:hep-ph/0209166v1 15 Sep 2002
QCD SUM RULES - A WORKING TOOL FOR HADRONIC PHYSICS
ALEXANDER KHODJAMIRIAN
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Institut f¨ ur Theoretische Teilchenphysik, Universit¨ at Karlsruhe, D-76128 Karlsruhe, Germany
1. Introduction Imagine a big birthday cake for Arkady Vainshtein, each candle on that cake corresponding to one of his outstanding contributions to the modern particle theory. I think, a very bright and illuminating candle should then mark QCD sum rules. The renown papers introducing QCD sum rules [ 1] have been published by Shifman, Vainshtein and Zakharov in 1979. The method, known also under the nickname of SVZ or ITEP sum rules, very soon became quite popular in the particle theory community, especially in Russia. Not only experienced theorists, but also many students of that time contributed to the development of this field with important results. It was indeed a lot of fun to start with an explicit QCD calculation in terms of quark-gluon Feynman diagrams and end up estimating dynamical characteristics of real hadrons. The flexibility and universality of the sum rule method allowed one to go from one interesting problem to another, describing, in the same framework, very different hadronic objects, from pions and nucleons to charmonium and B mesons. Nowadays, QCD sum rules are still being

基于Gogny相互作用的非对称核物质同位旋的相关性质

基于Gogny相互作用的非对称核物质同位旋的相关性质
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弱π缠绕模的Maschke型定理


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原子物理量子力学主要知识点复习

1.爱因斯坦关系是什么?什么是波粒二象性?答:爱因斯坦关系:⎪⎩⎪⎨⎧========k n n h n c h n c E p h hv Eλπλνπω22 其中 波粒二象性:光不仅具有波动性,而且还具有质量、动量、能量等粒子的内禀属性,就是由式n r =局限性:(1)不能解释较复杂原子甚至比氢稍复杂的氦原子的光谱;(2)不能给出光谱的谱线强度(相对强度);(3)从理论上讲,量子化概念的物理本质不清楚。

4.类氢体系量子化能级的表示,波数与光谱项的关系?答:类氢体系量子化能级的表示:()22202442nZ e E n πεμ-= 波数与光谱项的关系 ,4,5.3,3,5.2,121ˆ22=⎪⎭⎫ ⎝⎛-=n n R v了与氢原子能级的差别7.自旋假设内容,碱金属光谱精细结构特点?答:自旋假设内容:(1)电子具有自旋角动量s p,它在空间任何方向上的投影只能取两个值: 21±=sz p(2)电子具有自旋磁矩 s μ,它在空间任何方向上的投影只能取两个值:B sz sz me p m e μμ±=±=-=2 碱金属光谱精细结构特点:原子态:2523212121D 3,P 3,P 2,S 2,S 122222 ----n层数(表示L 的S,P,D,F )J ,其中电子总角动量J=轨道角动量L+自旋角动量S 。

电子自旋耦合:通过电子之间的自旋产生彼此的效果力。

9.碱土族元素光谱特点?答:Mg 的光谱与He 类似。

也形成两套线系,有两个主线系、两个第一辅线系、两个第二辅线系等等。

Mg 原子也有两套能级,一套是单层能级——单态,另一套是三层能级——三重态。

单层能级间的跃迁产生单线,三层能级间的跃迁产生多线光谱。

10.LS 耦合与jj 耦合过程?两种耦合方式的原子态表示?答:略L+S S 最J 值13.磁场中原子磁矩的表示及引起的能量差。

答:原子磁矩:φμp meiA 2==,而对于两个或两个以上电子的原子,其磁矩表达式为:J eJ P m egμ2=轨道磁矩:B el e l l l l l m e p m e μμ)1()1(22+=+==; 自旋磁矩:B es e s s s m e p m e μμ3)1(=+== ;总磁矩:()B j ej sl j j j j g p m e p p p p μμ12212222+⋅=⎥⎦⎤⎢⎢⎣⎡+-+=。

第2章 夸克与轻子 (2)

第二章夸克与轻子Quarks and leptons2.1 粒子园The particle zoo学习目标Learning objectives:我们怎样发现新粒子?能否预言新粒子?什么是奇异粒子?大纲参考:3.1.1 ̄太空入侵者宇宙射线是由包括太阳在内的恒星发射而在宇宙空间传播的高能粒子。

如果宇宙射线粒子进入地球大气层,就会产生寿命短暂的新粒子和反粒子以及光子。

所以,就有“太空入侵者”这种戏称。

发现宇宙射线之初,大多数物理学家都认为这种射线不是来自太空,而是来自地球本身的放射性物质。

当时物理学家兼业余气球旅行者维克托·赫斯(Victor Hess)就发现,在5000m高空处宇宙射线的离子效应要比地面显著得多,从而证明这种理论无法成立。

经过进一步研究,表明大多数宇宙射线都是高速运动的质子或较小原子核。

这类粒子与大气中气体原子发生碰撞,产生粒子和反粒子簇射,数量之大在地面都能探测到。

通过云室和其他探测仪,人类发现了寿命短暂的新粒子与其反粒子。

μ介子(muon)或“重电子”(符号μ)。

这是一种带负电的粒子,静止质量是电子的200多倍。

π介子(pion)。

这可以是一种带正电的粒子(π+)、带负电的粒子(π-)或中性不带电粒子(π0),静止质量大于μ介子但小于质子。

K介子(kaon)。

这可以是一种带正电的粒子(K+)、带负电的粒子(K-)或中性不带电粒子(K0),静止质量大于π介子但小于质子。

科学探索How Science Works不同寻常的预言An unusual prediction在发现上述三种粒子之前,日本物理学家汤川秀树(Hideki Yukawa)就预言,核子间的强核力存在交换粒子。

他认为交换粒子的作用范围不超过10-15m,并推断其质量在电子与质子之间。

由于这种离子的质量介于电子与质子之间,所以汤川就将这种粒子称为“介子”(mesons)。

一年后,卡尔·安德森拍摄的云室照片显示一条异常轨迹可能就是这类粒子所产生。

具有次二次双偶位势的二阶哈密顿系统多重非平凡奇周期解的存在性

0 多重非平凡奇周期解 的存在性.
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