量子理论若干基本问题研究的新进展

213Vol.21,No.320019PROGRESSINPHYSICSSept.,2001:1000O0542(2001)03O0317O44:2001O02O16:(ESI)(,100080):,BraggwhichOway,QEDC60,,,EPRBell,,,,,:;;;;EPRBell;:O437:A0,,(),,,,,[13],,,,[4]1927Solvay,[5],(1935)[6],EPR(1935)[7],(1932)[8],(1952)[9],Bell(1964,1981,1975)[1013],[1416]:,(complementarity),,[22],,,,,(Quantumdecoherence)[17,18],(Wavepacketcollapse):AAx,xpÜ(1)ApÜx,S,,(),,,,Rampe[19],,(Entangledstate)O,EPR,[1925],(),,,O,,,,,:,,[2630](),,O,,,:,1971,HeppColeman[31],81321(HC)N1/2;N,Bell[32]Cini[33],[3441]HC()j,[3641][1925],,,,,O1,,|nA,an,|f=ncn|nA,:A{an|n=0,1,2},|cn|2,(M.Born)|f,f(x)=x|fx,:,|f1|f2,|f=|f1+|f2,,|f|f1|f2,,,Ik=|fk(x)|2fk(x)=x|fk(k=1,2),f(x)=x|fI1(x)I2(x)I(x)=f(x)2=I1(x)+I2(x)+f1(x)f32(x)+f31(x)f2(x),(2),:,?an,,an|f=cn|n|n,fn[8],(Wavepacketcollapse)(Wavefunctionreduction),,,[14]:9132:1f(y)=y|fxyyp,,,f(y)fn(y)=y|n()[42],2,t=0A,t=T,p,|peipx,T,:BA,(AB2,)tT,B,,OT,,,B,AB,,[43],,,,,,,,,,,,,,|f=ncn|n:A,AB|mB,bm,|nbm|m|n|2|an|cn|2,bm02321Pm=ncn2mn2=mm=Tr(mm)(3),f=ncn2nn,(4),Tr,Tr(f)=mm||m,,,=ff=n,mcnc3mnm(5)f3(a),;(b),([3]),,,3,SC()[1],C,(,AB),,,,,,;,,(rank)11,,,,,2=(6),(6),=UU-1,(6)(6),|,==2=2(7)=1-1(6)12EPRBell,1232:EPR,(),(),EPR,,2,1,,(,,)EPR:1);2),,,1935,[1],12,12OEPR,12,,,12,,,,,1964,(J.Bell),EPR,,,,1964J.S.BellBell,Bell,1972,,,,EPR[2]p=0,,,p1p2,p1=-p2,,p1p21,p1=q,2p2=-q,,:1p1=q,,p1=q,p1=s,:p1=q,2,p2=-q,22232112,,EPRx1-x2p1+p2,[44]EPR=x,p=eip1x2xáp(8)|x|pxp1,p1,IDp1EPREPRp1(9)I=p-p1p-p1(10)2p-p1EPRBohm[45],EPR=12(+z,-z--z,+z)(11)4EPRz,zz,50%+z50%-z+z,|+z,-z,,z,,,,1/2,,,,,,EPRz,X,n(4),,,Sxx=12(+z-z)(12)EPREPR=12(-x,+x-+x,-x)(13),Sx,X,,,Sz,+1/2,Sz3232:-1/2,Sx,1250%,n,|EPR=12(-n,+n-+n,-n)(14),,,|EPR,,EPR,,Sz,Sx,:=12+z,-z+z,-z+12-z,+z-z,+z(15),,|x=12+x,-x+x,-x+12-x,+x-x,+x+nonOdiagonalterms(16)xOspin,EPR5Bell,EPR,Bell,BellBell:l(l);A1aa(Pauli)A(a,l),al,A(a,l)=1,l2bbB(b,l),b,B(b,)=1A(a,l)b,B(b,l)a;,a=b,A(a,l)=-B(b,l)abA(a,l)B(b,l)(5)l,l(l),(l)dl=1,(l)A(a,l)B(b,l)dl=A(a)B(b)(17)EPR|ªb|EPR.1a(a)2b(b)p=A(a)B(b)-A(a)B(b)=A(a)B(b)[1A(a)B(b)]42321-A(a)B(b)[1A(a)B(b)](18)A(a)B(b)1,A(a)B(b)1(19)p1A(a)B(b)+1A(a)B(b)(20),BellA(a)B(b)-A(a)B(b)2(A(a)B(b)+A(a)B(b))(21)a=b=c(),A(c)B(c)=-1A(b)B(c)=A(c)B(b)(21)A(a)B(b)-A(a)B(c)1+A(b)B(c)(22)Bell,1/2,Bell,a,b,c60,,,aábEPR():(á1+1á)EPR=0(a)(b)=ab+i(ab)(23)EPRaábEPR=-EPRabEPR=-ab-iEPRá1EPR=-ab=-cosab(24)ababab=/3,bc=/3,ca=2/3,,A(a)B(b)=-1/2,B(b)B(c)=-1/2,A(a)B(c)=1/2(25)(22),=|-1/2-1/2|=1,=1-1/2=1/2,Bell,AspectBell[11],5,Aspect,AspectBell,,1,2,SPDC(SpontaneusParametricDownConversion)Bell,Shih()AlleyKwiatStrekalov,Bell[13]5232:3(Entanglement)OEPR,,,,,,O,(whichOway)[3437],,|=nCn|n,=nCnnªen(26),{|en}|en,|nª|en,|n,EPR,|nª|en|n|en:,|n|en,Hilbert,6Bragg([3]),SternOGerlach(SG),[3]SG,,,RampeBraggwhichOway[19]Bragg(6),A,|-|,,,:H=p22m-Ü2g24cos2kx(27)62321=-aBragg[3]Bragg,,,BCBragg,BCDGEF;DEFG,785Rb,52P3/2|e,52S1/2F=2F=3|2|37([19])|2|3|2,|3,2=-g(2)0,3=-g(3)0(28)8BraggRabi([3])[17],(27),Bragg,,,|3,Bragg,,|2,BraggRampe,,|23GHz/2,Rabi,1/2(|3+|2),Bragg,1/2(|3-|2)B1/2(|3+|2)C;/2Rabi,B|2,C|3Rabi(8),,Bá2+Cá3,(29),(9),,,,,7232:9whichOway([19]),,,,,Rampe[19]whichOway[22](10),A,B,AharonovOBohm(AB),B,,,D,D(QPC),(Coulombblockade),D,DQPC,10whichOway,QPC,B,,=các+dád,(30)|c|dCD|c|dQPC,AB,,[20,21]4,WhichOway,,1935,,,,+,,{|n|n=1,2,,}Vs,|en82321,|n(preOquantummeasurement)(0)=(cnn)áe(31)(t)=(ncn(t)náen(32),|e;|en,(32)s(t)=cn2nn+mncnc3mnmemen(33)(),emen=3m(q)n(q)dq(34),qn,(q)=q|en,(11),:s(t)=cn2nn(35)11,,?,U(t)=ne-iEntnnáUn(t)(36)Un(t),|e|enA,,,H=Hs+HI+He=H0áI+nnnHn(37)H0=Ennn,Hn=i55tUn(t)U-1n(t)(38)9232:HI=Vn(x)nn,Vn=(Hn-He),(39),H[31,47]:[H0,HI]=0,[He,HI]0(40)(40),(),,,,,,,HeppHeppColeman,HeppHeppOColeman(HC)J.Bell[32],Bell,HeppHC(12),cP,1/21(0),2(0)3(0);N1/2,,HC12([3])H=cPx+12(1+3(0))Nj=1V(x-j)2(j),(41)V(x)x,i(j)(i=1,2,3;j=1,2,3,,N)jPauli1/2(1+3(0)),=10,=01,,e=ááá03321(x,0)=x(0)=(x)[(+)]áe()(x)=x|,|x(0)=|+|,HI=Nj=112V(x-j+ct)[1+3(0)]2(j),(42)UI(t)=Nj=1e-iF(x-j+ct)2(j)12[1+3(0)](43)F(x-j+ct)=t-V(x-j+ct)dt=1cx-j+ct-V(y)dyt(x,t)=U(t)(x,-)=(x-ct)(áNj=1áUj(t)+áe)(44)Uj(t)=e-iF(x-j)2(j)=cosF(x-j)-i2sinF(x-j)jV(x)-V(x)dx=/2,tF(x-j+ct)/2,U(t)(0)ááá(0)áá,U(t)(0)ááá(0)áá(45),,,N,,N,,,,zSz=12Nj=1(t)3(j)(t)+12N=2Nj=1sin2F(x-j)(46),t-V(y)dt,sin2F(x-j)DF2(x-j)V(x),Sz=2NV2t2vanHov:NV0VN=Trd((t)(t))=(x-ct)2(2+2+3F(N,t)+h.c.)(47)F(N,t)=Nj=1uj=Nj=1cosF(x-j)(48)1332:,|cosF(x-j)|1,F(x-j)n,(n=0,1,2,)N,F(N,t)0N,,NF(N,t),,HCHCNj=1j3(j),3(0),1992Namik,NakazatoPascazioHC,,,,,HC[3541],N,N,e=Nj=1e(j),en=Nj=1en(j),(49)Fmn(t)=Nj=1Fmn(j,t)Nj=1em(j)en(j),(50)|Fmn(j,t)|=|em(j)|en(j)1,N,N1,Fmn(t)N0,5QED,,,Haroche1996QED[23],,|a;Rabi,(0)=1/2(e+g)á(51)|g|e(),,,,(t)=1/2[eáei+gáe-i](52)=t2/,=-(I)(13)|g|eRydberg,5150,51.099GHz,30ms.CQFabryOPerol,Q5.1107,160s2332113([23]),/2=24kHzC,C010R1R2SQ,egRabi,SDeDg,105000,40%PgR1R2()Pg,RamseyeOgR1R2,,WhichOWay,R1,|