International Centre for Theoretical Phvsics

No. 718October 1987

1986 ICTP PrizeAlfred Kastlerto Li Jia Ming

Prof. Li Jia Ming from the Instituteof Physics of the Chinese Academy ofSciences was awarded the 1986 ICTPPrize for his outstanding contributionsin the field of atomic and molecularphysics. The prize was awarded at aspecial ceremony on 30 lvlarch, 1987, inthe Main Lecture Hall of theInternational Centre for TheoreticalPhysics in Trieste, Italy.

The ICTP Prize is named after the latehof. Alfred Kastler, Nobel Laureate inPhysics in 1966 and Chairman of theICTP Council from 1970 to 1983.

Professor Li was born on L6November 1945 and is an expert in themultichannel quantum defect theory(MQDD who has made significantcontribution owards the development ofthis theory. His main scientificachievements include: (l) theestablishment of the relativistic versionof MQTD; (2) the application of MQTDto photoionization, photode[achment andother processes with a large number ofgood results; (3) the establishment of themultiple scattering method forcalculating the MQTD physicalparameters, namely the energy levels ofmolecular Rydberg states; (4) theproposal of a method oo measure thecompressed core density of high-powerlaser imploded spherical target; (5) theinvestigation of aomic shell effect onthe equation of state at high lemperatureand high pressure and the application ofquantum electrodynamics to high energyatomic processes.

Professor Li has about 50 scientificpublications including three invitedpape$. He received his Ph.D. from theUniversity of Chicago in 1974 andworked as a a Associate at theDepartment of Physics of theuniversities of Chicago (1974) and.Pittsburgh (1975-1976) and as a SeniorResearch Associa0e at the Laboratory forLaser Energetics of the University of

Rochester (1977-1978\. He returned roChina in 1979 as an Associate Professorat the Chinese Academy of Sciences andwas appointed Professor in 1983.

The citation was read by ProfessorAMus Salam, Direcor of the ICTP andPresident of tlp Third Wcld Academy ofSciences, while the prize consisting of aUS$ 1,000 cheque, a medal and adiploma was handed to Professor Li byProfessor Louis Emmerij, President ofthe Development Centre of theOrganization for Economic Cooperationand Development in Paris.

Prof. Yu Lu of ICTP made apresentation of the work of Prof. Liwhile Mr. C:R. O'Neal of the ThirdWorld Academy of Sciences paid atribute to the memory of Prof. A.Kastler.

The ICTP 1983, 1984, and 1985Prizes were awarded !o three scientistsfrom Asia, Latin America and Africa inthe fields of solid state, plasma physicsand mathematics respectively.

1987 ICTP PrizeNikolaj N. Bogolubov

to Abdullah Sadiq

On 7 August at a special ceremony inhonour of the 300th anniversary of thepublication of the Principia by Sir IsaacNewton, held at the International Cenrefor Theoretical Physics (ICTP), inTrieste, Ialy, tlrc Centre's 1987 prize inhonour of Prof. Nikolaj N. Bogolubov,was awarded to Dr. Abdullah Sadiq ofPakistan. The prize was awarded inrecognition of Dr. Sadiqs contributionto scientific knowledge in the field ofSolid State Physics. His diverse researchinterests in condensed matter physicshave included Ising models, correlatedpercolation and its relations to spin glasstransition and long chain polymers. Hehas been active in the area of computersimulation of physical systems and hiscurent studies relate to the kinetics ofirreversible chemical processes. Dr.Sadiq is a saff member of the Pakistan

Institute of Nuclear Science andTechnology in Rawalpindi, Pakistan.

Contents

19t6 ICTP Prize - A. Kastler 1

19t7 ICTP Prize .N. Bogolubov

1986 Dirac MedalsAward Cerenony

l

2

19t7 Dirac Medals to De\Mittand Zumino 3

TWAS Awards

Geophysics at ICTP

High-TemperatureSuperconductivity

3

4

1987 Nobel Prize for Physics 7

7Association of Visitorsto the ICTP

ICSU and Third.\MorldScientists: Reflectionsover 30 Years 8

First Meeting of APCB 10

lorld Lab Supports theEstablishment of CCAST 10

Constrained Systems 11

Third ltrorld Must DevelopOwn Technology L2

A New International Centre 13

Distinguished Guest at ICTP:Sir Rudolf Peierls 13

Directory of Physicistsfrom Developing Countries L4

Future Activities at ICTP 14

News from ICTP - No. 7/8 - October 1987

Dr. Sadiq was born in Peshawar,Pakistan in 1940. He has devotedhimself to research in various fieldsrelated to solid state physics for morethan 17 years, and has to date publishedsome 20 papers. He plans to continuehis activities in this area of physics andis currently working on kinetics ofirreversible processes.

and the world scientific community forhis achievements. He has been elected anhonorary member of various nationalAcademies of Science, such as that ofthe USA, the Federal Republic ofGermany, Poland, Bulgaria and theGerman Democratic Republic.

As part of the ceremonies as well,Professor Bogolubov and thee other

Dr. A. Sadiq (right) receiving the award from Professor Bogolubov (left),middle, Prefetto E. de Felice.

In the

Professor Bogolubov presented theaward, consisting of a medal, a certificateand a cheque in the amount of US$1,000, in front of more than 200scientists from all over the world. Prof.Bogolubov who was born in Gorky,USSR in 1909, wrote his first scientificpaper at the age of 14 and received hisdoctorate in mathematics from theUSSR Academy of Sciences at the ageof 2L. He has since made decisivecontributions in the fields ofmathematical physics, non-linearmechanics, quantum statistics, thetheory of superconductivity, nucleartheory, quantum field theory andelementary particle physics. Among hismany contributions were thedevelopment of the methods of secondquantization as well as a brilliantphysical explanation for thephenomenon of superfluidity, theconstruction of the famous Bogolubovtransformation, and the introduction ofBogolubov's microcausality condition inthe field of quantum theory. PrcfessorBogolubov has received some df thehighest awards from the Soviet Union

distinguished individuals were honoured,and presented with ICTP Medals.Professor Bogolubov was the firstrecipient and the award was presented byProfessor Abdus Salam (Nobel Laureale1979), Director of the ICTP andPresident of ttre Third World Academy ofSciences. While Professor Salam readthe individual citations, ProfessorBogolubov then presented the othermedals to Dr. Eustachio de Felice ofTrieste, Sir Rudolf Peierls and hofessorJohn Ziman.

During the course of the ceremonies,which took place in the morning andaftemoon, lectures were given by severaldistinguished professors from the UnitedKingdom, including John Ziman on theDevelopment of Scientific Thought afterNewton, Sir Rudolf Peierls on theMeaning of Models, Hypotheses andApproximation, James Eells onVariational Theory, Alan Cook on theSystem of the World, and DennisSciama on Cosmology, Asfronomy andFundamental Physics.

1986 Dirac MedalAward Ceremonv

On Thusday 23 July 1987, one of the1986 Dirac Medals of the InternationalCentre for Theoretical Physics (ICTP) inTrieste was officially given to ProfessorYoichiro Nambu @nrico Fermi Institutefor Nuclear Studies, Chicago University,USA) by Professor Abdus Salam,Director of the ICTP, and ProfessorHerwig Schopper, Director General ofCERN.

More than three hundred scientists andofficials attended the award ceremonywhich took place in the Main LectureHall of the ICTP during the two-dayConference "Search for Scalar Particles:Experimental and Theoretical Aspects".

After the Medal was handed over,Professor Nambu lectured on BSCMechanisms in Nuclear Physics.

Professor Yoichiro Nambu washonoured "for being one of the firstphysicists to formulate the idea ofspontaneous symmetry breaking and, inparticular, chiral symmetry breaking inrelativistic particle physics. Hiscontributions to the quark model in thesixties and, later, his geometricalformularton of the dual resonance modelsas the dynamics of a relativistic stringare of fundamental importance. Thescope and intensity of cunent research instring theory are witness to theprofundity of Nambu's contibutions toparticle physics".

Professor Yoichiro Nambu was bomin Tokyo on 18 January 1921. Hestudied at ttre University of Tokyo wherehe received his B.Sc. in 1942 and hisD.Sc. in 1951. He was appointed as aProfessor at the Osaka City Universityin 1950. After two years as a Memberof the Institute for Advanced Study ofPrinceton (1952-1954), Prof. Nambujoined the University of Chicago as aResearch Associate (1954-1956) first andthen as an Associate Professor (1956-1958). He has been a full Professorsince 1958. He was Chairman of theDepartment of Physics from 1974 tot977.

Professor Nambu is a member of theNational Academy of Sciences (since1971), American Academy of Arts andSciences (since 1971) and an HonoraryMember of the Japan Academy (since1984). He has received the followingawards: Dannie Heineman Prize forMathematical Physics (1970),Distinguished Service Professor

News from ICTP - No. 7/8 - October 1987

Professor Y. Nambu and Professor Abdus salam at the ICTp Dirac vedal Awardceremony.

(University of Chicago, l97l), 1. RoberrOppenheimer Pnze 9976), Harry PrattJudson Distinguished Service Professor(1977), Order of Culture awarded by theGovernment of Japan, United StatesNational Medal of Science (1982) andl a x Planck Medal (1985).

He is the author of 126 scientificpapers.

The other 1986 Dirac Medal wasgiven to Professor Alexander Polyakov(Landau Institute for TheoreticalPhysics, Moscow, USSR) on 15November 1986.

1987 Dirac Medalsto DeWitt and Zumino

The Dirac Medal, instituted by theInternational Centre for TheoreticalPhysics in 1985 to honour the memoryof the eminent physicist, was awarded inAugust, 1987 to Professor BrunoZumino and Professor Bryce S. Dewittfor their outstanding contribution totheoretical physics.

Prof. Zumino has been for the lasttwenty years one of the leading expertsin field theory. Together with prof.Julius Wess he has made fundamentalcontributions to the study of chiralanomalies in gauge theories withfermions. Also in collaboration with

Prof. Wess, he proposed the firstrenormalizable Lagrangian field ttreoriesto realize supersymmetry in 4-dimensional space-time. With prof.SAnley Deser he constructed one of thefirst supergravity theories in fourdimensions. In addition to thisimportant early work, he has been aleader in the application of moderngeometrical ideas in field theory. Inparticular he has illuminated the role ofK[hler geometry in extendedsupergravities and, more generally, thevalue of differential geometric mettroOsin the study of anomalies.

Prof. Bryce S. De Witt has madefundamental contributions to the studyof classical and quantum gravity andnon-Abelian gauge theory. Hispioneering work with quantum, effectiveaction underlies much of the modernformalism. Particularly important arethe background field method which heinvented, and the methodology of ghostloops in gauge theory, which he didmuch to develop. His name isassociated with the Wheeler-DelVittequation, which provides the basis formost work on quantum cosmology, andwith the Schwinger-DeWitt expansion,which is widely used in srudying fieldtheories in curved space-time anC insfing theory computations.

TWAS Awards

The Council of the Third WorldAcademy of Sciences upon therecommendation of the TWAS AwardsCommittee has decided to award thefollowing four Prizes for the year 1986.The prizes will be presented to scientistsfrom developing countries who havemade singular contributions to basicsciences.

Physics - Prof. Zhong-xian Zhao(China) - for his fund.amental andpioneering contributions to hightemperature superconductivity, inparticular for achieving thesuperconductivity above liquid nitrogentemryraturc in Ba-Y-Cu-O system.

Chemistry . Prof. Saad S.M.Hassan @gyp$ - for his fundamentalcontributions to Modern AnalyticalChemistry, in particular for developingnew simple and selective micromethodsfor tlrc analysis of pharmaceutical andbionudical compounds.

Biology - Prof. MysoreAnanthamurthy Viswamira (lndn) -forhis fundamental contributions to theunderstanding of DNA structure, inparticular for his discovery of seqtilncedependent fine stucture in DNAsegments in single crystals.

Mathematics - Prof. MauricioMatos Peixoto (Brazit) - for hisfundamental and pioneering study ofstructural stability of dynamicalsystems, in particular for proving tlatflmts on closed surfaces re genericallystrucntrally sable.

Each prize will consist of an award ofTen Thousand Dollars and a Medal. Thepresentation of these Awards will takeplace in Beijing, China, at the GreatHall of People on 14 September 198? atthe ceremonial session of the ThirdWorld Academy's Second GeneralConference: "The Future of Science inChina and the Third World".

News from ICTP - No. 7lE - October 1987

Geophysics at ICTP

by Atan Cookr

Courses on geophysical topics havebeen held at the Cenre for many of thepast nrenty-ttree years and I shall showin this article that geophysics isparticularly appropriate for the Centre,alike for its international nature and itstheoretical problems and also because onit rests our understanding andexploitation of our natural world, indeveloping and in industrialisedsocieties. The physical study of theworld beneath our feet and of the seas,atmosphere and plasmas around it, beganwhen the Greeks first gained some ideaof the size of the Earth, but in a modernsense the first geophysicist was WilliamGilbert (t 1603), a student first at St.John's College, Cambridge (the collegeof Dirac and Abdus Salam) and then ofthe famous rnedical school of Padova.He constructed in the manner of themodern scientific method a model of themagnetic field of the Earth which, so faras it goes, is very much in accord withour present knowledge, but the real startof geophysics came a century later, withIsaac Newton and Edmond llalley, whosecontributions to physics we particularlyrecall in 1987. Newon applied his ideaof universal gravitation to calculate theshape of the Earth, demonstrating thatthe polar axis was shorter than any axisin the equator, and also that theattraction of gravity should be greater atthe poles than on the equator. He drewupon some observations of thependulum ttnt llalley had made as a veryyoung man at St. Helena, as well asother more recent observations of thesize of the Earth and of the length of theseconds pendulum, to compare with histheory. Cassini, in Paris, had proposedthat the polar axis of the Earth was thelongest; the settlement of the conflictinvolved careful measurements inLapland and Peru which confirmedNewton, were the origin of moderngeodesy and led eventually tointemational agreement on the metricsystem in which the metre was definedas l/40,000,000 of the length of ameridian. Much of Halley's scientificwork arose from his concern with

' Pro[essor Alan. Cook is thc Master ofSelwyn College in Combridge. He hasbeen involved as Director ard Lecturer inaU the ICTP activities in geophysics.

seamanship and navigation, he observedthe magnetic field and the tides from aship at sea, he studied the world-widesystem of winds and he found from thestudy of ancient eclipses that, as wewould say now, the spin of the Earth isslowing down. Of the main fields ofgeophysics, two were unknown toNewton and his successors - seismologyand the ionised gases and magnetic fieldsaround the Earth.

Geophysics as we know it o-day hasdeveloped over the last fifty years,mainly through the application of threetechniques o geophysical observation -the measurement of geophysicalquantities from ships at sea, the use ofspace craft in geophysical studies, andthe use of very powerful compu0ers.Until the 1.930's, geophysicalobservation had been effectively confinedto the land, after that time, andespecially from about 1950 onwards,measurements of gravity and of magneticfields, but above all, seismicobservations, were made in the deepoceans and completely altered ideas aboutthe nature of continents and oceans, assummarised in the concept of platetectonics. Traditional studies of themagnetic field and the size and shape ofthe Earth were greatly helped by spacetechniques, but a new realm was openedwith the discovery early in the history ofsalellite observations, of the van Allenradiation and of the magnetosphere,while in very recent years, ways ofmaking better synoptic observations ofthe oceans are being devised. Satelliteobservations can be exceedinglynumerous, as indeed, are many othersmade by modern methods, and they couldnot be used without computers toorganise them. Computers are not justfiling systems, they are also used tomanage the observations, while muchtheoretical work depends on computersbeing available. Geophysics deals withthe whole world, world-wideobservations are needed, of quantitiesthat vary in time, and computers arenecessary to get a grasp of the results.The use of very powerful computersmeant that advanced geophysics wasuntil recently developed in a fewindustrialised countries, but now that somuch can be done on microcomputers,physicists and mathematicians indeveloping countries can do comparableoriginal work. Geophysics isinternational - geophysics confined toone country would be ludicrous to-day -and it is also highly theoretical. Thetheoretical concepts and mathematicaltechniques are no less demanding and

rewarding than in the most advancedfields of physics, so that it is whollyappropriate that theoretical geophysicsshould be pursued in the InlernationalCentre. Furthermore, geophysics has farreaching practical applications in scienceand technology in developing countries.In the following sections of this article,I will say more about some theoreticalproblems and give a hint of howgeophysical studies bear upondevelopmenL

Geophysics falls naturally into twoparts - internal geophysics, dealing withthe interior of the Earth, inaccessible asit is o direct observation, and externalgeophysics which studies the fluids onand around the Earth. There is afundamental distinction between themethods of the trvo branches; in externalgeophysics the physical properties of theregion can be observed directly,especially with the aid of space craft,whereas the internal properties have tobe inferred from observations at thesurface of the Earth. One wishes to findsome physical property of the Earth(density, elastic moduli, heat generation,and so on) as a function of positionwithin it, but the observations are offunctionals evaluated at the surface (suchas gravity, travel times of elastic wavesbehveen points on the surface, heat flow,magnetic field). The mathematicalproblem is to infer the function from thefunctional. It cannot be solved uniquelyor exactly, only within some range, andthe study of the methods and scope ofsolutions is the province of inverseth*ry, which has been developed in avery sophisticated and elaborate mannerin terms of Hilbert space theory. Besidethe general theory, each farticular fieldof study requires a solution of theappropriate direct problem, thecalculation of the functional from aspecified function. The direct problemsare aspects of classical physics, but thatdoes not mean they are elementary. TheEarth when shocked by a largeearthquake, vibrates as a whole in acomplex superposition of normal modes;the calculation of the eigenfunctions andeigenperiods and the way in which theydepend on the rotation of the Earth(analogous to the Zenman effect inatoms) and its ellipticity requirespowerful mathematics similar in someways to that for alomic structure theory.Again, the study of the transmission ofelastic waves through the Earth has closeanalogies with the theory ofelectromagnetic waves in plasmaswhich, of course, is the basis of much ofthe study of the plasmas around the

News from ICTP - No. 7/8 - October 1987

Earth. While they may be elaborate andsophisticated, the bases of these theoriesare classical and deterministic. It ishowever, now well understood that notall solutions of the equations of classicalphysics are well determined and thatsome may behave in a random andchaotic manner. Chaotic conditions mayquite well obtain in the behaviour of theoceans, the theory of which is one of theoutstanding major problems of classicalphysics. Only quite recently, by meansof satellite observations, has it becomepossible to observe the sea surface atmore than the very few isolated pointson ships' tracks, and even when thoseobservations will have been made isadequate numbers and over a sufficientspace of time, much of the behaviour ofthe oceans in depth will still beunknown. Correspondingly, importantaspects of the theory are obscure anddifficult. The intluence of geometry iscomplex because of the inegular andasymmetrical shapes of the ocean basins,there are considerable non-linearinteractions and one of the principaldriving forces, the action of the wind atthe surface, is as yet poorly understood.To describe and account for thebehaviour of the oceans is a greatchallenge to human intellect.

Geophysics can stand on its own as ascientific activity, but at the same time,there are important connexions withother fields of physics and chemisry.Geophysics calls upon much ofrheology, of plasma physics, solid statephysics among others, to interpret itsphenomena, but at the same time itretums 0o laboratory physics ideas whichmight not have occurred if it were onlyin the laboratory that physics werestudied. Thus, rhe idea and theory of thehigh pressure metallic s[ate of hydrogenhad their origin over fifty years ago inthoughts about the interior of the Earth,and observations of Jupiter and Saturnfrom space craft have led to much recentwork on that subject, which raises manyof the fundamental issues of the theorvof metals and of our understanding of thlliquid state. These and otherdevelopments in the behaviour ofcondensed matter at very high pressures,were explored three years ago in ICTp ata joint working group of the condensedmat0er and geophysics programmes.

While the theorerical problems andscientific interest of geophysics would,on their own account, justify aprogramme of theoretical geophysics atthe ICTP, the importance of anunderstanding of geophysics for the wayswe live in and use our Earttr, especially

in developing countries, adds weight tothat scientific justification. Theapplications of geophysics to human lifeare indeed many. Locally, geophysicalmethods are used extensively in lookingfor oil, minerals, water and otheisubstances that are economicallvimportant or on which the existence of icommunity may depend. Developingcountries which may want 0o find theirown indigenous resources needgeophysics and geophysicists.Countries with sea coasts need a goodknowledge of their oceanographicconditions, for building ports, oridentifying areas subject to floods, andso on, and that simple, essentialknowledge is often quite lrcking. Thenagain, a good understanding of thetropical ionosphere is needed forplanning radio communications inEopical lands. Important though theseimmediately practical matters are todeveloping countries, the significance ofgeophysics goes much further. Mostpeople in most parts of the world areunaware of the physical processes thatshape and control our world, and of thelimits they set as well as thepossibilities they offer for changing theworld Eo our benefit and profit In manyindustrialised countries that is anunhappy but not a disastrous state ofaffairs, but in some developing countriesit is much more serious, for many ofthose countries are especially subject tonatural disasters, from storm, or flood,or earthquake or volcanoes or drought,and some natuml conditions may be verysensitive to changes man brings about,as changes at the margins of desertsseem to show. Education in thephysical state of the world is verynecessary in most developing countries.There is a further way in whichgeophysics can contribute to education,for the phenomena of the world aroundus afford many examples of theprinciples of classical physics that mightbe more economically and effectivelyused in teaching physics, in universityand in school, than demonstrationstaken over from laboratory practice inindustrialised countries, for which theapparatus is apt to be expensive,sophisticated and difficult to keep inorder by local technicians.

The uses of geophysics thus rangewidely, from fundamental theory toseverely practical industrial use, with theadvancement of education in physics anddevelopment of understanding of whatwe can and cannot do with nature as vervimportant. All those aspects have haitheir place in the geophysics programme

of the ICTP over the past two decadesand there is every reason why all shouldbe extended in the future.

High TemperatureSuperconductivity

by Yu LuSenior Scientist, ICTP

The discovery of room temperaturesuperconductivity has been a long-standing dream of many condensedmatter physicists. The technologicalimplications of such a discovery inelectronics, power industries and so onare expected !o be really tremendous.Until 1986, the painfully slow progressin raising the superconducting Eansitiontemperature had made most physicistsquite pessimistic about the possibility ofever materialising this dream.

A revolutionary breakthrough came inearly 1986 when G. Bednorz and A.Miiller of the IBM Zurich ResearchLaboratory first found the signature ofsuperconductivity in the temperaturerange 30°K in the La-Ba-Cu-O system.Later on, this result has been confirmedby themselves, and has also beenconfirmed and extended by other grcupsin Japan, China, and in the U.S.A. OnFebruary 16 this year, the USA NationalScience Foundation announced at a pressconference that the team led by p. Chuhad observed onset of superconductivityat temperatures as high as 92"K.However, Chu did not reveal thechemical composition of the compound.On February M, the Chinese Academyof Sciences in Beijing announced thatthe research team led by Zhao Zhongxianhad observed superconductivity up to100'K in an oxide of yttrium, bariumand copper. From then on, the race forhigher Tg started. The perspectives ofsuch high temperature superconductorsfor applications are so attractive and theproblems arising in understanding thesuperconductivity mechanism are sochallenging that a major fraction of bothexperimentalists and theorists incondensed matter physics have rushedinto this field instantaneously. Almostall major laboratories all over the worldhave been involved in this high Ts"heatwave", a spectacular demonstration ofwhich was the "Woodstock" meeting ofthe American Physical Society held onMarch 18 in New York and ended at3:15 the next morning.

News from ICTP - No. 7/E - October 1987

A special Adriatico ResearchConference "High TemperatureSuperconductors" took place on July 5-8, right on the crest of this "heat wave"at the International Centre forThmretical Physics (ICTP) in Trieste toprovide a forum for a discussion of thelatest developments in this extremelyrapidly moving field. This conferenceco-sponsored by the ICTP, the SISSA(International School for AdvancedStudies - Trieste) and IBM Italy, hasbeen a first ruly international meetingon this subject with about 200 registeredparticipants and over 300 actual arendeesincluding scientists from otherdisciplines, top-level managers andjournalists.

reported at this Conference (theproceedings will be published very soonby the World Scientific PublishingCompany in Singapore). However, wewould like to give here a very briefdescription of the current status in thisfield. These oxide superconductors aredistinguished from the ordinarysuperconductors in many ways. Firstly,they are characterized by special layer-like, or even chain-like structures ofcopper and oxygen ions. Secondly, thesuperconductivity properties (criticaltemperature, energy gap, the specificheat jumps at the transition temperatureand so on) are extremely sensitive to theoxygen deficiency and, therefore, to theway of sample preparation. It is well

Professor Stig Lundqvist (front), Chairman of the ICTP Scientific Cormcil and movingspirit of the Adriatico Conferences, with Prof. R. Schrieffer, Nobel Prize 1972 (right).

The response of the worlds scientificcommunity to this Conference has beenexEemely wann. More than 60 invitedpapers were presented covering all majordevelopments in materials experiments,theory and applications of hightemperature of superconductors.Scientists from more than 35 countriesall over the world including Africa, Asia,Europe, Oceania, South and NorthAmerica, have communicated their latestachievements. Some of the speakers hadbeen invited only a few days before theconference because of tlte unusual pacein this field. Nevertheless, theymanaged to come and to share with othercolleagues their "hot" results.

It is impossible to summarize in afew words the numerous exciting results

known that superconductors show zeroelectrical resistance and perfectdiamagnetism (Meissner effect).However, the Meissner effect is notcomplete for these high temperaturesuperconductors, even in the bestsamples available. On the other hand,there are clear-cut experiments showingthe macroscopically quantum nature ofthe superconducting state in theseoxides, namely the magnetic fluxquantization and the Josephson tunnelingbetween these and the ordinarysuperconductors.

The theoretical explanation of whythe transition temperature for suchsuperconductors is so high, is a greatchallenge to the condensed matter theory.For thirty years, following the

microscopic theory advanced by Bardeen,Cooper and Schrieffer, the interaction ofelectrons with phonons (sound waves)leading 0o electron pouring, was the onlydocumented mechanism forsuperconductivity. It is doubtful that thesuperconductivity in these oxides can beentirely explained by this theory. Thereare some strong experimental indicationssupporting that viewpoint. u p to nowthere are two families for high Ts

superconductors. The La-Cu-O systemdoped with Ba or Sr with transitiontemperature around 90"K. For the La-Cu-O system, the undoped compound isan antiferromagnetic insulator while thesuperconductivity transition temperatureupon doping is strongly correlated withthe whole concentration measured by theHall effecr Also, there is an additionaloptical absorption in the insulating gapin both systems when the compositiondeviates from the stoichiometric one.Previously, the isotope effect - thetransition temperature is inverselyproportional to the square root of theisotope mass - has been a direct evidencefor the phonon mechanism. Howeverthe yttrium superconductors do not showany isotope effect at all, whereas onlypartial isoope effect has been observedin lanthanum superconductors.

At the moment, more than a dozen oftteoretical models have been proposed ointerpret this new type ofsuperconductivity. All of them shouldbe scrutinized and selected by furtherexperiments.

The race for higher T s is stillcontinuing. From time to time there arereports on 240" K or even roomtemperature superconductivity.However, up to now, the reproduciblesuperconductivity is still in the 90'Krange. The big advantage of oxidesuperconductors is their easyaccessibility to most developingcountries. In fact, they have alreadybrought in their own contributions. Asmentioned before, China was among thefirst to confirm and extend thepioneering discovery of Bednorz andMtiller. Professor Zhao Zhongxian ftomthe Institute of Physics, AcademiaSinica, Beijing, has been awarded the1987 Thtud World Academy of SciencesPrize in Physics for his outstandingcontributions to this field. India hasvery sEong teams working on oxidecompounds. Nowadays even high-school s0rdents in advarrced countries canmake their own s4mples and demonstratethe striking "floating" effects ofsuperconductivity (see the article by Paul

News from ICTP - No. 7/8 - October 1987

1987 Nobel Prize for Phvsics

On going to press, we learn that Professor Alex Muller and hofessor Georg Bednorzshare the 1987 Nobel Prize for Physics in recognition of their work on high-temperattre superconductors. Our congratulations to the two Laureates.

The Centre was fortrmate in having Professor Miiller as a lecturer at the AdriaticoConference on High-Temperature Superconductors,

The photograph shows him attending a lecture in the main auditorium at the ICTP.

Grant in New Scientisr, 30 July 1987).To polarize the research on the high Tg

superconductors in developing counFies,tbe ICTP will hold an "ExperimentalWorkshop on High TemperatureSupe.rconductors" on April ll-22, 1988.Many leading experts and laboratories inthis field are giving advice andassistance in this activity. Theattendants of this workshop will notonly listen to the latest state-of-artlectures but will also make samples andcarry out physical measurementsthernselves.

The 1987 special AdriaticoConference on High-TemperatureSuperconductors was a great success.All the major laboraories involved fromboth the West and the East, tJredeveloping and developed world, werewell represented at this exciting event.Even leading experts in this field havegot new inspiration at this Conferenceand have started new projects as soon asthey got back home. However, this isonly a start but not the end of an heroicchapter in physics. Many questionsremain open and challenging. Tocontinue the efforts along this line, theICTP is going to organize two moreactivities on this subjecr in 1988: a

mini-workshop on "Mechanisms ofHigh-Temperature Superconductivity",June 20 - July 29, co-sponsored bySISSA, and an Adriatico Conference on"Towards Theoretical Understanding ofHigh-Temperature Superconductivity",laly 26-29, co-sponsored by SISSA andIBM ltaly. The first activity is aresearch-oriented special-purposeworkshop with a small but meaningfulfraction of actively working scientists inthis field in the same spirir as rheWorkshop on "Nonlinear ChargeDensity Wave Systems" held in 1987.The Adriatico Conference willconcentrate on a critical overview of themain experimental results in this fieldand an in-depth discussion of themechanisms leading to the high-temperature superconductivity.

Association of Visitorsto the ICTP

(AVTCT)

On 9 September 1987, theAssociation of Visitors to theInternational Centre for Theoretical

Physics (AVICT) was constituted at theICTP.

The aim of AVICT will be to:(a) propagate the ideals of ICTP

(functioning like an alumnibssociation) and advocate the use ofscience for peace and prosperity;

(b) promote international contact andco-operation for scientific activities,supplementing the efforts of ICTPand making them effective;

(c) advocate the involvement ofscientists in national developmentalefforts, especially in developingcounfties; and

(@ express collective views publicly innational and inlemational forums onscience policy matters likeadministration, education, budgetand management of research anddevelopment in science andtechnology.

All the visitors to ICTP are eligibleto become members of AVICT.

The most important pafis of AVICTwill be the local and regional chapterswhose activities will be carried out by anexecutive committee consisting of apresident, a vice-president, a treasurer, asecretary and some executive committeemembers. Apart from other activities,the local chapters must meet once a yearand elect its executive committee.Ipcmrer and discussions on topics relatedo the aim of AVICT can be arranged by

the regional chapters. Regionalorganizations of visilors to ICTP whichalready exist can become regionalchapters of AVICT without loss ofidentity.

The overall co-ordination will be doneby the AVICT general executivecommittee based at ICTP; Trieste. TheDirecor of ICTP will be the Patron ofAVICT.

The general executive committee willhave a term of two years for itspresident, vice-president, fieasurer andsecretary who will be elected in one ofthe s111rrel meetings held at ICTP. Thepresidents and secretaries of localchapters will be members of the generalexecutive committee. Some additionalmembers may also be elected.

The General Secreary will operate theBank account of AVICT along with theGeneral Treasner.

Life membership fee will be US$ l.-,payable to AVICT ac(nunr with Cassa diRisparmio di Trieste. Donations toAVICT may be paid into rhe above-mentioned bank account. Regional andlocal chapters of AVICT may seekseparab donations and contributions fortheir activities.

News from ICTP - No. 7/8 - October 1987

Changes in the constitution can bedone in annual meetings of AVICT atICTP, Trieste, by a simple majority ofvot€s.

The following visiors were elected tothe General Executive Council ofAVICT:

President: Professor S. Lundqvist,Institute of Theoretical Physics,Chalmers University of Technology, S-41296 Gdteborg, Sweden;

Vice-president: Professor A.A.M.Sayigh, Department of Engineering,University of Reading, Whiteknights,P.O. Box 225, Reading RG6 2AY, UK;

General Secretary: Professor M.Yussouff, Departement of Physics,I.I.T., Kanpur, India (presently visitingFakultat Physik, Universitlt Konstanz,Konstanz, D-7750 Konstanz 1, FederalRepublic of Germany);

General Treasurer: Professor AMulAziz Sabir, Department of Mathematicsand Statistics, University of Agriculture,Faisalabad, Pakistan.

ICSU andThird World Scientists:

Reflections Over 30 Years

F.W.G. Bakzr,ICSU Executive Secretary

As part of a presentation about ICSU,Mohamed l{assan asked me o look backover thirty years of work in ICSU toreflect on some of the changes that haveoccurred between 1957 and 1987especially with regard to the ThirdWorld.

ICSU, which brings together in aloose federation, 20 InternationalScientific Unions, 74 Nationalmembers, Associates and Observers, 24Scientific Associates and over 20Scientific and Standing Committees,Commissions and Groups, is the largestinternational non-governmentalorganization in the natural and physicalsciences. ICSU's principal objective isto encourage international scientificacrivity for the benefit of mankind. Ithas been responsible for initiating,designing and coordinating a number ofmajor global interdisciplinary researchprogrammes such as the InternationalGeophysical Year (1957-58), the UpperMantle Project (1961-70), theInternational Biological Programme(1964-74), etc. It is currentlydeveloping a study of the interactionsbetween various parts of the geosphere

and biosphere known as the GlobalChange Programme. In addition, it hasbeen responsible, with members of theUN family, for launching a number ofprogrammes such as the InternationalIndian Ogean Expedition, the WorldScience and Technology InformationSystem, the International GeologicalCorrelation Programme, a study ofClimate Change and the Oceans, and theIntemational Biosciences Nenvork withUNESCO, and the Global AtmosphericResearch Programme and the WorldClimate Research Programme withWMO, and others.

ICSU also acts as a focus for theexchange of ideas, the communication ofscientific information and thedevelopment of scientific standards,nomenclature, units, etc., and incomparison of methods andintercalibration of instruments. Variousmembers of the ICSU family organizescientific conferences, congresses,symposia, summer schools, andmeetings of experts, as well as GeneralAssemblies in many parts of the worldas well as other meetings to decidepolicies and programmes. A wide rangeof publications is produced, includingnewsletters, handbooks, proceedings ofmeetings, congresses and symposia,professional scientific journals, da'ra,standards, etc. Some of these arepublished by the ICSU Press. ICSUalso assists in the creation ofinternational and regional networks ofscientists with similar interests, and itinitiates special studies such as those onRadioactive Waste Disposal and on theDisposal of Toxic Wastes, and thatcarried out by SCOPE on theEnvironmental Consequences of NuclearWar (ENUWAR).

The first thing that struck me inFebruary 1957 when I joined theSecretariat of the InternationalGeophysical Year was the deep interestin Africa. The Secretary General of theIGY Committee was attending inBukava the joint IGY/CSA meeting ofcoordination for the IGY in Africa Southof the Sahara which was examining how!o improve the network of stations inAfrica.

One of the reasons for this and otherregional meetings was the interest of thegeophysicists to obtain as complete acover as possible of the Eafih and itsatmosphere using ground-or-sea-basedobserving platforms with a few countrieslaunching rockets and a much largernumber launching instrumentedballoons. Africa was one of thecontinents with the least dense network

of stations, and a plan was developedwith UNESCO and WMO to help rainAfrican geophysicists and to install newstations in key locations. Although thenetwork of stations and of scientists inAfrica is still less dense than in manyother parts of the world, combinedefforts - with UNESCO particularlyrecently in the framework of the AfricanBiosciences Network and in thosedeveloped by IUGG and IUG Sciencesand with WMO in the framework of theGARP and WCRP - have improvedconsiderably the situation. It is sad tonote that the network of these stationsestablished in Africa for the GARPAtlantic tropical Experiment has notbeen maintained, and important gaps inthe observational network in Africa have

But it was not only in Africa. Otherparts of the Third World were assisted byICSU with the strong support ofUNESCO and WMO so that when theIGY began on I July 1957 there werecountries from the Third Worldparticipating. (It is interesting to notein passing that in the First InternationalPolar Year of 1882-83 - one of thepredecessors of the IGY - there wereseven stations in the Third Worldmaking observations, most of them inthe ropics!).

There was not, however, a focus forICSU activities in the Third World untilthe early 60's when a small study goupwas established o look into the questionof what ICSU might do to helpdeveloping countries. The report of thisgroup w:ls instrumental in the decisionmade by the 12th General Assembly heldat the Tata Institute of FundamentalResearch in Bombay in January 196f tnestablish a Committee on Science andTechnology for Developing Countries(COSTED). I believe that another factorwhich influenced some of the delegatesin their decision was their first contactwith people of the Third World and asharp realization of the conditions underwhich some of them existed.

COSTED began to function in 1966under the Chairmanship of PatrickBlacken with the writer as Secretary. Inits first six years the Committee madecon0acts with the developing countriesalready adhering to ICSU and soughttheir advice. It also stimulated others tojoin ICSU. The most successfulprogramme was that of sending one ormore experts in answer to requests fromNational Members in the Third World.

The first of these was a group ofexperts in land use who went toIndonesia in 1967. The Indonesian

News from ICTP - No. 7/8 - October 1987

authorities brought oogether most of theIndonesian scientists involved in landuse for a series of discussions and anexchange of views about the Indonesiansituation. Similar missions wereorganized to other countries in the ThirdWorld at their request.

The last mission organized byCOSTED under Blacketts leadership wasone to East Africa in 1968. It was at thetime when ICSU and UNESCO werecarrying out the feasibility study for aWorld Scientific Information System(LiNISISTS). A specialist in scienceinformation was sent to East Africa atthe request of the East African Academyof Science to study the possibilities ofcreating a scientific information cenEefor the region. The report was sent bythe East African Academy to a UN bodywith a request that funds be madeavailable to help set up the Centre.Unfortunately, none were madeavailable.

The Chairman suggested that all themembers of COSTED should givelectures at the University of Nairobiwhen COSTED held its meeting there in1969. Only one lecture was given to asmall audience: the start of the lecturesunfortunately coincided with a strike ofthe students which lasted longer than thestay of the potential lecturers in Nairobi.

Perhaps the most interesting studyduring this early part of COSTED'sexistence, however, was that of howscience and technology could be appliedto the economic and social betterment ofthe developing countries: a subject longdear to Blackett's heart. COSTEDdecided to prepaxe a small book with theutJe Tlu Role of Science & Technologyin Developing Countries. An author,Graham Jones, was engaged to work fortwo years under Blackett's direction witlrthe costs shared by ICSU and the RoyalSociety. In the introduction Blackettdescribes the contents of the book asfollows: "Thc content of the book wasplanned taking fully into account thelarge literarure already existing on theproblems of tlrc developing cauntries.This literanre covers a very wide rangeof subject and form, from wide globalsurveys to highly detailed studies.However, many of these studies are hardto come by and only a small fraction ofthem could be studied in detail by aworking Qualified Scientist or Engincer(QSE), if only for lack of time. Thebook therefore contains an extensivebibliography and many of the previousstudies are critically evaluated in thetext. One reason why it was thoughtthqt such a book would be timelv is that

in recent years important advances inunderstanding have been, both in theDCs and the LDCs, of just how theprocess of innovation take place -rneaning by tlu word 'innovation' thewlwle process from scientiftc discoveryor invention to tlrc final emergence of amarketable product, or a social service".He goes on to say "To get science andtechnology used to best adavantage forthe benefit of the LDCs, it is notsufficient tlat a few top economic andsocial planners should understand whatshould be done: this must also bewtdcrstood in the research laboratory, atthe industrial work bench and in thefields. Thus a somewlwt flippant andeven presumptuous sub-title of thisbook might be What Every QSE Oughtto Know". The book was published byOxford University Press in 1971 and waslater translated into and published inSpanish.

The preparation of this book provideda stimulus to the USSR Academy ofSciences which prepared a book entitledThe Third World and Scientiftc TechnicalProgress published in 1976 in Englishby the Nauka Publishing House,Moscow. In his introduction, A.P.Vinogradov states: "The present work,which expresses the views of a groups ofSoviet sclnlars, is such a publication.It reflects the results of investigationsinto the utilisation of science andtechnology in developing countries,carried out in recent years by variousinstitutes of the USSR Academy ofSciences, including a scientificconference - "The Scientific andTechnical Revolution and theDeveloping Cotntries", luld in Moscowin February 1971."

There is a great deal of wisdom inthese two books that continues to berediscovered.

The first phase of COSTED'sactivities ended in Helsinki in 1972when an Ad hoc Group under thechairmanship of S. Bhagavantam made arecommendarton: "The Assembly Ad lncWorking Group on DevelopmentalIssues under thc chairmanship of Dr. S.Blnganntam, made a recommendation,which the Assembly adopted, thatCOSTED be continued with a smallCommittee of nine members, drawnfrom all parts of the world andrepresenting different philosophies ofdevelopment, with the following basicobjectives: to coordinate and toencourage the Unions' assistance todeveloping countries; to encourageparticipation by scientists of developingcountries in the Special and Scientific

Committees; to foster regional tonational affiliations in whichidentiftcation of developmental scientificand technical' problems would befurtlured; to prwide liaison and dvisoryservices to international scientificdevelopment organizations".

Bhagavantam became Chairman ofCOSTED in 1972, and a new phasebegan with the establishment of theCOSTED Secretariat in India where itstill is today tlnnks to the generosity ofthe Indian authorities and of the IndianLeather Research Institute.

One of the major developments inICSU in the last 30 yeans has been thegrowth in the number of members of theICSU family. In 1957 there were 13International Scientific UnionsMembers, now tlere are 20, and 24Scientific Associates. In 1957 ICSUUnions and Committees had adheringorganizations in 60 countries and now in118 so that most of the countries of theThird World are now involved in theactivities of the ICSU family. But it isin the developoment of the Scientific andSpecial Committees, which have theresponsibility for internationalinterdisciplinary programmes, that thegreatest change has taken place. h 1957there was only one Special Committee(for the IGY) and now there are 1lScientific or Special Committees forinterdisciplinary studies in Antarctic,Oceanic, Space and liy'ater Research,Science and Technology in DevelopingCountries, Teaching of Scierrce, Data forScience and Technology, GeneticExperimentation, Biotechnology, theGeosphere-Biosphere Programme, etc.All of these have programmes ofparticular relevance to scientists and tothe population of countries in the ThirdWorld in general.

Another area in which there has beenan interesting series of stop-godevelopments is in relation with themedia and the question of visibility.Although relations with the media wasnot one of the first concerns of theSpecial Committee for the InternationalGeophysical Year, the launching of thefirst Sputnik in 1957 brought the IGY,and to a lesser extent ICSU, to thepublic eye. ICSU did not profit greatlyfrom being in the limelight as can beseen by the fact that already in 1960ICSU set up a Committee on PublicUnderstanding of the Objectives of ICSUwhich was asked to review ways andmeans by which the objectives of ICSUshould become fully known to theworking scientists of the world, and tothis end, to examine the possibilities of

News from ICTP - No. 7/8 - October 1987

closer liaison: a) with the moreimportant world scientific newsperiodicals and b) with the leadingnational newspapers in countriesadhering to ICSU, and with the principalwodd news agencies.

Several such reviews have taken placesince then, but a ceriain reluctance [o beinvolved with the media has untilrecently remained a feature of thescientists who have been members of theICSU Executive Board. The RingbergConference in October 1985 once againdrew attention to the need for ICSU toincrease its visibility and tocommunica0e better with scientists, withdecision-makers and the general public asa whole. An Ad hoc Group on ICSU,the Scientific Community and theMedia, held a meeting in January 1987that brought together representatives ofICSU and a number of sciencecommunicators.

Looking back over thirty years ofworking with ICSU, one of the moststriking things is the srongly developeddesire for cooperation between scientistsof different countries and disciplines. Inspite of the various cold and wann warsthat have occurred and continue to occur,the universality of science and globalcooperation among scientists form acomparatively peaceful island of hope inthe world of today. One region of theworld where science is a dominant force,Antarctica, remains an unchallengedexample of what is possible. Let ushope that when the Antarctic Treatycomes up for renewal in 1999 sense willprevail and Antarctica will continue tobe a peaceful demonstration of friendshipamong scientists of the world.

First Meetingof The Association

for the Advarrcenrnt of Phys icsin the Caribbean Basin

F. Brouersl

The first meeting of the Associationfor the Advancement of Physics (ArcB)in the Caribbean Basin was held, from30 March to 10 April 1987, in MonaCampus, a pleasant site well equippedfor teaching activities belonging to theUniversity of the West Indies (UWI) in

Prof. F. Brouers b a Senior AssociateMember of tle ICTP. He is curreilty atthe Department of Physics, University ofthe West Indies, Kingston 7, Janaica.

Jamaica. This university has theunusual distinction of being aninternational, rather than a nationalinstitution, with presently more than11,000 students from 14 English-speaking Caribbean territories. Themeeting had an international character;speakers were from the USA, Europe,South America and the Caribbean Basin.The high level of the lecturers wascombined with a simole but effectiveapproach. The lecturei offered a broadselection of science research topics,which are being developed in the mostadvanced countries, as well as theCaribbean region, with emphasis on theamorphous state, porous materials,ceramics and rocks. The atmosphere wasoptimistic and markedly influenced by arecent break-through (high temperaturesuperconductivity) in solid state physics.The audience mostly from the academicworld of the Caribbean Basin, Centraland South America, played an active rolein the seminars and discussions. All thegraduate students in materials science andenergy from the three campuses@abdos, Jamaica and Trinidad) att€ndedthe meeting. There was significantparticipation from the academic staff inphysics, chemistry and geology fromUWI, the College of Art, Science andTechnology (CAST), the ScienrificResearch Council, public and privatesector institutions, and from professionalbodies and associations in Jamaica.Among the highlights of the meeringwas the demonstrated interest of theacademic and political authorities in theperspectives offered by internationalcooperation in the field of science andtechnology.

It was fortunate that the workshopcame so closely on the heels of theJamaica Society of Scientists andTechnologists award dinner, where Prof.Abdus Salam gave the key address inwhich he suggested that the scientistsshould be allowed to play a moreimportant role in the effort of nationbuilding, technological development andpolicy decision making in the ThirdWorld. The addresses of Prof. Seraphinand the Hon. Don Mills, an eminentJamaican personality, at the ConferenceBanquet, chaired by Dr. Taylor,Executive Director of the ScientificResearch Council of Jamaica, were inthe same genre. Both speaken developedthe theme of "self reliance and the needto stimulate local scientific developmentto solve local problems". Theysuggested that these scientists workingin the Third World and to some extent inpartial isolation from the wider

scientific community could possiblyestablish and maintain contact throughthe ICTP, TWAS and other similarorganizations.

Along thesb lines, considering thatJamaica has a richness of clay, limestoneand alumina, and that the University ofthe West Indies has good facilities inmaterials scierrces and thin films, a broadactivity in ceramics cermets, thin films,and physics of rocks should beconsidered as a priority. The setup andupgrading of the related facilities shouldalso be included. This research hasstarted with a grant from TWAS to Prof.F. Brouers.

As for energy, a realistic startingpoint could be the characterization ofmaterials and components, with a viewto the design of suitable systems for izsitz applications.

As far as the Association for theAdvancement of Physics in theCaribbean Basin is concerned, thefollowing committee has been electedduring the general meeting on 10 April,1987:Chairperson: Prof. E. Morillo deEscobar, El SalvadocExecutive Secretary and contact personwith CLAF: Prof. F. Brouers, Jamaica;Treasurer: Prof. Gonzalez, Colombia;Deputy Secretary ard contact personwith ICTP: Prof. Lopez Pineda,Honduras and Ialy;Members:Prof. Saunders, Trinidad and Tobago;Prof. Mosely, Barba&s;Prof. Nieves, Puerto Rico;Prof. Trallero, Cuba;Prof. Negrete, Venezuela.

The organization has been founded bythe ICTP Associates of the region. It isopen to all scientists of the CaribbeanBasin, essentially the islands and CennalAmerica. The participation of physicissfrom Colombia, Mexico and Venezuelawho work in fields overlapping theregional interests is also welcomed.

The lecturers and participants of theWest Indies have expressed the wish tofind a way !o be integrated into theLINESCO-CLAF network.

World Lab Supportsthe Establishment of CCAST

At the Annual General Assembly ofthe World Laboratory, held in Geneva on27 luly, 1987, the President, Prof. A.Zichichi, announced the approval of theScientific Committee to support the

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establishment of the China Cente forAdvanced Science and Technology(CCAST). The World Lab will providefunds for purchasing necessaryequipment and for running theprogrirmmes of the Cenre. The Chinesegovernment will provide the buildingand support the personnel.

In describing the structure andprogrammes of the new centre, Prof.T.D. Lee, the Director of the Cenhe,informed ttre assembly that CCAST willconsist of four divisions: TheoreticalPhysics, Condensed Matter Physics,High Energy and Sychrotron Radiation,and Astronomy and Astrophysics.Thirty five eminent Chinese scientistshave been selected as members of theTheoretical Physics division and an equalnumber of experimental physicists havebeen selec0ed for the Condensed Ivlatterand High Energy and SynchrotronRadiation divisions. Prof. Lee indicatedthat the main objective of tlre Centre isto carry out world class research work inthese fields and estimated that about 200research papers will be published ininternational journals by members ofCCAST every year. The World Lab isfinanced by the Govemment of Italy.

Constrained Systems

by Victor TapiaInternational School

for Advarced Studies,Trieste

Constrained systems play afundamental role in contemporaryphysics. In fact, all physically sensibletheories must be constrained systems.This is due to the general covariance, orreparametrisation invariance, requirementfor them. We are not going !o showwhy this is so [cf. 1.]; instead, weconcentrate our efforts to exhibit whatthe general structure of a constrainedsystem is. The formalism to deal withconstrained systems was first developedby Dirac f2., 3., and 4., cf. also 1., 5.,and 6.1.

In order to show how constrainedsystems appear, we restrict thearguments to classical mechanics wherea dynamical system is described by aLagrangian L=L(qi,qi), where qi, withi=1, ..., N, are generalised coordinates.The generalisation to field theorypresents only minor technical problems.In order to integate the Euler-Lagrangeequations, it is necessary to haveW=detwij different from zero, where

Wij=3i<jjL is the Hessian matrix;Yij=6i6jI-di=E0it. In this case the Lagrangian iscalled regular. The number of initialdaa which can be given independently isI=2N. The number of degrees of freedomis f=W. For a regular lagrangian f=N.

If W=0, then the solution of theEuler-Lagrange equations containsarbitrary functions. This corresponds toa constrained or singular system. Beforegoing to deal extensively withconstrained systems, it is useful toremember some fundamentals of theIlamiltonian formalism where they finda proper mathematical setting.

The canonical Hamiltonian Hs

depends only on the variables (qp) wherepi is the canonical momentumconjugated to qi ' this is h generalproperty of the Legendre transformationdefining the Hamiltonian independent ofthe regularity of the Lagrangian. Thefundamental variables of theIlamiltonian formalism are the canonicalvariables (q,p) spanning the 2N-dimensional phase space Q. So onemust solve for the velocities in term of(q,p). The necessary condirion for doingthat is to have W*O.

The time evolution of anydynamical quantity p'=F(qB) is given bythe canonical Hamilonian together withthe Poisson bracket. When F is putequal to the canonical variables, oneobtains the Hamilton equations. Thenecessary condition in order to have theequivalence between the Hamilton andthe Euler-Lagrange equations is W+0.

For a constrained system W=0.Then rank Wij=M.N and the Hessianmatrix has K=N-M null eigenvectors.Contracting the Euler-Lagrangeequations with these null eigenvectors,one obtains K relations g6(q,{)=0 wherea=1,...,K. Some of these relations, K1,let us say, are identities. They areindependent of the validity of theequations of motion and correspond tothe reparametrisation invariance of theaction. The rest, K2 = K - K 1 , arerelations between the coordinates and thevelocities. These are the constraints.Not all the 2N initial data can be givenindependently, they must satisfy theconstraints, therefore the number ofdegrees of freedom is lesser than N. Foran extensive treatment of constraints atthe l"agrangian level [cf. 5].

At the Hamiltonian level theprevious relations translate to $a(q,p)=Qand restrict the dynamics to unfold on a(2N-K)-dimensional submanifold, I , of(l. Constraints appearing in this way

are called primary to emphasize that theequations of motion have not been usedto obtain them, only the form of theI-agrangian.

The Hamilton equations are notequivalent to the Euler-Lagrange ones.This is due to the fact that theconstraints do not appear either in He orin the Poisson bracket. Thus, in orderto obtain the correct equations ofmotion, one must take account of theconstraints modifying either IIs or thePoisson bracket (or both).

By definition, constraints are zero onE, but not on its neighbourhood; oneexpresses this fact by writing $u=Q,where '=' is the weak equality signdifferent from the usual strong one Vvalid on X. Now, all dynamicalquantities must be defined in theneighbourhood of E, i.e., weakly. It canbe shown that two weakly equalquantities differ at most by a linearcombination of the constraints. 8.g.,for the canonical Hamiltonian oneobtains the extended one HsxpHc+USawhere the U's are, at the momentarbitrary, Lagrange multipliers. Since,in general, constraints have non-nullPoisson brackets with the canonicalvariables, the weak equalities becomestrong ones only after all the Poissonbrackets have been evaluated, i.e., whenthe equations of motion have beenexplicitly wrinen.

Constraints are classified in first-class, yp, F=1,...,R=K-J, and second-class, 1g, d, = 1,...,J. First-classconstraints correspond to the gaugeinvariance of the systgm and theyindividually weakly commute with allother constraints. Second-classconstraints correspond fo redundancies inthe definition of the canonical variables;

they satisfy det{Id,rgp})+o.The extended Hamiltonian is now

writEen as llexfllc+uCI1s+vpyp. Thetime-evolution of a dynamical quantity Fis now given by the extendedHamiltonian plus the Poisson bracket.According to Dirac, at this point onemust impose as consistence condition,in order to guarant€e that under the time-evolution induced by tlext the dynamics

does not go out of I , that the constraintsbe preserved in time. Then one is ableto delermine the J Lagrange multipliers

u o . The other R, vF , remainsundetermined and completely arbirary.

Some of the consistence conditionscan give rise to extra relations on the

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News from ICTP - No. 7/8 - October 1987

canonical variables. According to Dirac,these must be neated on the samefooting as the primary consEaints; theyare called secondary constraints. Thesituation is now as before imposing theconsistence conditions. There is thecanonical Hamiltonian and a set ofprimary and secondary constraints. Theprevious procedure must be applied untilall the consistence conditions aresatisfied. One finally ends with R' first-class and J' second-class constraints.The time evolution of a dynamicalquantity F is given by an extendedIlamiltonian containing all, primary andsecondary, constraints together with thePoisson bracket.

The }lamilton equations contain R'arbitrary Lagrange multipliers, evenwhen the physical situation they describeis the same. One already knows of asimilar situation in theoretical physics,namely gauge theories. Any ambiguityin the value of the dynamical quantitiesmust be a physically irrelevant one.This ambiguity is due only to the first-class constraints in the extendedHamiltonian. It can be shown that thefirst-class constraints are the generatingfunctions of transformations which donot change the physical state of thesystem i.e., of gauge transformations.Usually gauge theories are dealt withusing the Fadeev-Popov ghostformalism. It can be shown [7,8] thatboth formalisms are equivalent.

When only first-class consraints arepresent, the Poisson bracket of twoconstraints is a linear combination of the

constraints (Tp,11r1)=Cpv\6. tftneC'sare constant, as happens in Yang-Millstheories, they correspond, since the t'sare the gauge symmetry generators, tothe structure constants of the gaugesymmetry group. If the C's depend onthe canonical variables, one can define aseries of higher-order structure functions.The relevance of them to the physicalworld is at the quantum-mechanical levelof the theory through the Becchi-Rouet-Stora-Tyutin (BRST) operator [9,10]. Adetailed account of this can be found in[11,12]. The Dirac conjectureestablishes that all, primary andsecondary, first-class constraints aregenerators of gauge transformations.

The main motivation of Dirac was,in his own words, "to Hamiltonise asingular Lagrangian". This can be donewhen only second-class constraints arepresent. The dynamical evolution of thesystem is given in terms of thecanonical llamiltonian together with theDirac bracket. The main property of the

Dirac bracket is to be identically zerowhen one of the entries is a second-classconstraint. This allows to put thesecond-class consEaints strongly equal ozero; they are used just to consfuct theDirac bracket after which they can bedisposed of. The evolution equationsdefine a dynamics restricted to a (2N-J)-dimensional E and, since second-classconstraints are now sEongly zero, onecan consider as independent canonicalvariables a subset of (2N-J) of theoriginal ones. Then, by the Darboux

theorem, one can find new variables Qcr,P s , on X such that [Q,P]*=6; (,]* is theDirac b'racket

If first-class constraints are alsopresent, then they must be transformedin second-class. This was done by Diracin his work on gravitation t3l byintroducing another kind of constraints,namely, the gauge constraints, Vp, notimplied by the form of the Lagrangian.In order to have all the constraints ofsecond-class, it must be det{1p,ryy}*0.

This is nothing more than fixing thegauge. Now quantization can be done asfor a standard system, but this, as theBRST theory, merits separateconsideration.

1. K. Sundermeyer, ConstrainedDynamics, LNP 169, Springer-Verlag, Berlin, 1982.

2. P.A.M. Diac, Canad. J. Math . 2,r29, 1950.

3. P.A.M. Ditac, Proc. Roy. Soc.,London, Ser. A 240, 326, 1958.

4. P.A.M. Dtac, Lectures on QuantumMechanics, Belfer Graduate Schoolof Science, Yeshiva University,New York 1964.

5. E.C.C. Sudarshan and N. Mukunda,Classical Dynarnics: A ModernPerspective, John Wiley, New York,L974.

6. A.J. Hanson, T. Regge and C.Teitelboim, ConstrainedHamiltonian Systems, AccademiaNazionale dei Lincei, Rome, 1976.

7. L.D. Fadeev, Theor. Math. Phys. l,3, L969.

8. L.D. Fadeev and V.N. Popov, Plrys.Lett. B 25, 30, 1967.

9. C. Becchi, A. Rouet and R. Stora,Ann. Phys., New York, 98, 287,r976.

10. I.V. Tyutin, Preprint LebedevPhysics Institute N. 39, 1975.

11. M. Henneaux, Phys. Rep. 120, I,1985.

12. I.A. Batalin and E.S. Fradkin,Rivista Nuovo Cim., 10, 1, 1986.

Development:Third World Must Develop

Own Technology,Scientist Says

By courtesy o/ SUNS,Special United Nations Service,

No. 1668. 7 March 1987

Third World countries must undergo amajor cultural transformation !o copewith their need for rapid development inthe field of science and technology, aleading Brazilian physicist said.

"A country where carnival, soccer andindiscipline are tlw most important partsof culture, has lesser possibilities ofcultural interface with modern scienceand technology", the scientist SergioMascarenhas said at a meeting withexperts from the United Nations. Themeeting was organised by the U.N.Center for science and technology fordevelopment (CSTD).

lascarenhas, a fmrner professor at theUniversities of Harvard, Princeton andLondon, and at the MassachusettsInstitute of Technology (MIT), iscurrently the direc0or of bio-medicalphysics at the U.N. Center for Physicsin Trieste, as well as a prbfessor at theUniversity of Sf,o Paulo, Brazil.

Brazilian scientists are discoveringtheir own capabilities in the fields ofcomputers, energy and biotechnologyamong others as the result of financialrestraints imposed on their country bythe foreign debt, lvlascarenhas explained.

"Our job is to make the most out ofthe crisis, to improve our situation.And I wish Brazil had sblected ad-hoccrises, because they show lnw peopleare able to face tlu challenge", he said.

Brazil is the Third World's mostindebted country, with externalobligations of 108 billion dollars, andlast month its government imposed aunilateral moratorium on interestpayments.

To cope with the need for a newsocial approach to science andtechnology, Mascarenhas proposed thereform of the whole educational systemof Third World nations and the creationof regional scientific centres for theyoung through South-Southcooperation.

Simultaneously, he added, ThirdWorld countries should establishtransnational corporations withgovernmental support to boosttechnological research and ake advantage

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of huge Third World markets such asBrazil. According to Mascarenhas, theBrazilian market for pharmaceuticalproducts currently reaches six billiondollars a year, the electronics andinformatics market, four billion dollars,and the high-tech medical equipmentmarket earns one billion.

He also proposed the establishment ofregional science and technologyorganisations within the framework ofthe U.N. system, to monitor the degreeof scientific development in each countryaccording to previously set standards.

lascarenhas asserted that Third Worldcountries have no choice but to rapidlyachieve the level of knowledge andknow-how indusrialised countries have.And that requires a strong politicalcommitment from governments.

He sharply criticised the existingacademic structures in developingcountries — mainly national academiesof sciences — which in most cases arecomposed, he said, of "old people whogot those positions by designation andare daing twthing."

"I only believe in individualsdetermined to make the dffirencethrough their own work," he added.

Mascarenhas himself is leading a teamof experts and students in his homecountry to develop endogenous solutionsto practical problems -— likeunderstanding the motion of water insoils to create and improve irrigationsystems in the mostly semi-desert areasof northeastern Brazil. Mascarenhas'team applied computerised topographyscanning techniques derived from medicalscience to observe the motion of waterin soils. They then modified a micro-computer and designed special softwareto carry out the job, saving 450,000dollars in the process. The irrigationproject for northeastern Brazil includescomputerised meteorological stations,and will be able to irrigate two millionhectares of land in the next two years.

The scientist warned, however, thatdespite remarkable achievements byBrazil, India, Argentina and othercountries, industrialised nations aredoing far better because of their largerfinancial resources and because of theclose relationships between industry,government, universities and researchinstitutions.

According to Mascarenhas, there is nosuch thing as "technology transfer"between North and South, but ratler alarge sale of "black boxes full of buttonsthat only increase dependence" on theNorth.

What Third World countries need, headded, is a process of cultural adaptationsimilar to that experienced by Japan inthe 19th century, and beginning withchanging the aninrdes of children and thescientists themselves. "We'll getnothing in meetings with developedcountries' universities, governments orindustries. We'll get what we arelooking for through live exchangebetween individttols and scientists whobelong to the same club", be sud.

After all, he concluded, the ThirdWorld cannot rely on the past because itis gone, and it must not be afraid of thefuture because "the only thing we haveis the future."

A New International Centre

The International Centre for AppliedSciences $CAS) was inaugurated inGradisca d'Isonzo on 28 September1987. The main objective of the Centreis to promote international scientific andtechnological co-operation, particularlywith developing countries, in the fieldsof energy resources, mineral andmetallurgical processing, plant designand optimization of industrial processes.The ceremony took place at PalazzoTorriani, a beautiful 17th-centurybuilding of the Gradisca Municipality,made available to ICAS for this occasionas well as a temporary seat for itsactivities.

After the addresses of the President ofICAS and of the dignitaries from theTown, the Province and the Region,Professor Abdus Salam, Director of theInternational Centre for TheoreticalPhysics and President of the Third WorldAcademy of Sciences, expressed hiswishes for a successful enterprise andgave a lecture on the present status ofthe theory of elementary particles.

The President of ICAS is ProfessorHassan Dalafi, rector of the Universityfor Science and Technology of Teheran(Iran) until mid 1980. He joined theICTP and the International School forAdvanced Studies (ISAS-SISSA) inSeptember 1980 as a research physicirtfirst and took up the duties of scientificliaison as well as other responsibilitiesin 1983. The Membership of ICASinclude distinguished personalities fromthe academic world and indusrialiss.

The first 8-day workshop of ICASstarted on I Ocober and was devoted tothe improvement of joint interpretationof geophysical and geological data. For

the time being, ICAS will cater mainlyfor Europea.n scientists but ils soon as itsresource basis improves, it will extendits invitations to scientists from theThird World. ICAS has another sevenworkshops on board until the end of1987.

Distinguished Guest at ICIP:Sir Rudolf Peierls

Professor Ernest Rudolf Peierls wasthe honoured guest of the ICTP from 6to 28 August. He stayed at the AdriaticoGuest House and from there he couldwitness the Summer programme inCondensed Matter Physics. Though hehas reached the age of 80, Sir Rudolf

took an extremely active interest in theways of operation and, in particular, inthe guidance of the younger generationof physicists by their senior colleagues.After his return home, he wrote hissuggestions to the Direcor of the ICTP,Professor Abdus Salam.

Sir Rudolf has had many assignments;first in Manchester and Cambridge,before World War II, then the lt'fanhattanProject and, after tlte war, Birmingham,Oxford and Washington University untilretirement. He was knighted in 1986 byQueen Elizabeth. His publications, inaddition to his scientific papers, include:Quantum Theory of Solids; The Laws ofNature; Surpises in Theoretical Physicsand, Bird of Pctssage (an autobiography).

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News from ICTP - No. 7/8 - October 1987

Directony of Physicistsfrom lleveloping eountries

Last year, the ICTP issued apreliminary version of a Directory ofPhysicists from Developing Countrieswith about 1,000 entries. A secondversion with 2,700 names will bepublished in December 1987.

The CenEe is aware that the Directoryas it is now is far from being completeand, therefore, rsquests the collaboration

of all ICTP former Associates, VisitingScientists, Course Lecturers andParticipants. Anyone who did not havethe opportunity to fill out thequestionnaire for the Directory areinvited to write to:

Directory of Physicists fromDeveloping CountriesICTPStrada Costiera, 11P.O. Box 58634136 TRIESTEITALY

Their names will be included in the1988 version. We remind that thecriteria for inclusion are:• qualification of Doctor in Physics (or

its equivalent);• in cases where the last academic

qualification is a Master of Sciencedegree (or its equivalent), theauthorship of a minimum of threepublications in international journalsor, alternatively, three patents.

We thank those who have checked theentries of their own countries and havesent us additional information.

Future Actir,'ities at ICTF

1987Fourth College on Microprocessors: Technolosy and Applications in PhysicsCollese on Soil PhysicsCollege on Riemann SurfacesSecond Workshop on Cloud Physics and Climate

1988College on Variational AnalysisSpin and Polarization Dynamics in Nuclear and Particle PhysicsSecond School on Advanced Techniques of Computing in PhysicsWorkshop on Functional-analytic Methods in Complex Analysisand Applications to Partial Differential EouationsWorkshop on Applied Nuclear Theory and Nuclear Technology Ap'olicationsWinter College on I:ser Physics: Semiconductor Iasers and Intesrated OoticsWorkshop on Ontical Fibre CommunicationImpact of Digital Microelectronics and Microprocessors on Particle PhysicsExperimental Workshop on High-Temperature SuDerconductorsSprine School and Worlshop on SuoerstrinqsSchool on Non-accelerator PhysicsSpring College in Condensed Maner Physics: The Interaction of Atoms and Moleculeswith Solid SurfacesWorkshop on Boundary Layer and Wind ModellingCourse on Physical Climatology and Meteoroloey for Environmental Aoolications\{ini-Workshop on "Mechanisms of High-temperature Superconductivity"Summer School in High-Energy Physics and CosmologyResearch Workshop in Condensed Matter. Atomic and Molecular PhvsicsUnoccupied Electronic StatesComDuler Simulation Technioues for the Studv of Microscooic PhenomenaTowards the Theoretical Understanding of High T" SuperconductorsFifth Trieste Semiconductor SymDosium OUPAP) on SuperlatticesSummer School and Workshoo on Dynamical SvstemsThe Application of lasers in Surface ScienceWorking Party on "Electron TransDort in Small Systems"Frontier Sources for Frontier SpectrosconvSummer workshop on Dynamical SystemsFourth Summer Collese in BiophysicsCourse on Ocean Waves and TidesAfrican Regional College on Microprocessors (Yamoussoukro. Ivorv Coast)

5-30 October2 -20 November9 November -18 December23 November -18 December

I I Jaruam - 5 Februsv12 -15 Jannm18 Janwn -12 Febrwn

8-19 Febnnn15 Febrwm -18 March22 Febntrv -11 March14-25 March28-30 March11-22 Aoil1I -22 Aoril25 Aoril -5 May

25 April -17 June16 - 20 Mn23 Mav-17 Jrne20 June-29 Julv27 June -5 Aupust20 June - 30 Sentember2I-24 June19 -22 Julv26-29 JuIy812 Aupust16 Aupust - 23 Sentember23 - 26 Aupust29 aupust -16 Seotember30 Aupust - 2 Seotember5 - 23 Seotember12 Seotember - 7 October26 Septemher - 28 OctoberSeotember - October

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News from ICTP - No. 7/8 - October 1987

contd.

Collese on Medical Phvsics l0 Oitober - 4 NovemberWorkshoo in lvlathematical Ecolosv 3l October-18 NovemberCollese on Neuroohvsics 7 November - 2 DecemberWorkshop on Global Geophysical Informatics with Applications to Researchin Earthouake Predictions and Reduction of Seismic Risk 15 Novemfur -16 DecentfurColleee on Global Geometric and Toooloeical Methods in Analvsis 21 November -16 Decemfur

1989Winkr: Collese on Atomic and Molecular Phvsics

Workshop on lvfathematics in IndustryCollese on Aeronomv and GeomasnetismWorkshop in Mathematics

Sorins: Workshoo on SuoerstrinssWorkshon on Nondestructive TestinsColleee on Material ScienceWorkshoo in MathematicsCollese on Plasma Physics

Swnmer: Summer Workshoo in Hish Enersv Physics and CosmolosySummer Workshop in Condensed Matter, Atomic and Molecular Physics, ircluding Adriatico Conferences andWorkins Partv

Arttttmn: Wnrkshrrn on None-onventional F.nersv SorrrcesCollese on MicroorocessorsColleoe on Soil PhvsicsCollese in MathematicsCollese on Cloud Phvsics

For information and applications to courses, kindly write to the Scientific Programme Office.

l5

Ners fr$B. ICTP - No. 7/E - OctobGr 1937

Intemational Centre for Theoretical Physics Telephone: (40') 22.401of IAEA and LJNESCO Cablq CENTRATOMStrada Costiera 11 Teler 460392 ICTP IP.O. Box 586 Telefax: (4O) 22.4L.6334136 Trieste, Italy

EDITORIAL NOTE - News from ICTP il not an official document of the International Centre for Theoretical Physics. Its purpose is tokeql scientists informed on past and future activities at the Centre and initiatives in their home countries. Suggestions andcriticisms should be addressed to Dr. AM. Hamende, Chief Administrative and Scientific Information Officer.

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