Francesco Calogero

I had the privilege of meeting Prof. Calogero at one of the NEEDS meetings in Kolympari. He later visited the Institute of Theoretical Mechanics at the University of Ghent—my alma mater—as well as the Royal Flemish Academy of Belgium for Science and the Arts, where he spoke about his work in mathematical physics and his involvement with the Pugwash Conferences.

I will always remember Prof. Calogero as a distinguished scientist and humanitarian, someone unfailingly honest, warm, supportive, and generous with his time. His passing is deeply saddening, yet his influence endures through his writings, his mentorship of students and young colleagues, and his lasting contributions to the Pugwash movement.

My heartfelt condolences go out to his family and friends.

Willy Hereman, Professor Emeritus and former Head,
Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, Colorado, USA

Dearest Francesco,

You are going to be dearly missed, not only by your family and friends, but also by generations of physicists, like myself, and Pugwashites, also like myself, to whom you have been such a constant source of inspiration for so many years, and since my first Pugwash Conference in Lillehammer in 1997 to me.

I maintain the best memories of skiing with you in Andalo, having aperitivos here in Amsterdam, dining together in Paris, and having many discussions on world affairs and nuclear disarmament and non-proliferation at so many Pugwash conferences and workshop around the world, including at the Pugwash Conference we hosted ourselves in The Hague in 2009.

Fond memories remain, and I am thankful to you for the rest of my life for all your original thoughts and stimulating ideas - you will live on in my mind as you do in others’, and I here say a final goodbye to you. And, of course, the final word of this message should be the one with which you always ended mails yourself, which I wish to you and all those around you,

Peace,

Bob van der Zwaan

The first time I met Francesco Calogero, it was back in 2008, when I was doing research for my MA thesis in International History. He didn’t put any distance between himself and a young university student as myself. He made you feel at ease, in every conversation, you could perceive at the same time the prestige of the person, but also his humanity, sympathy, irony.
Then, I was so lucky to be involved in ISODARCO, founded by Edoardo Amaldi and Carlo Schaerf back in 1966 and still very alive, Therefore, I had the privilege of better knowing Francesco as a man, colleague, even friend.

Nella sua ultima mail mi scriveva:
E pensiamo con ottimismo al futuro (anche se ci vuole molta fantasia)!!!
Mi voglio per sempre ricordare della sua presenza affettuosa, della sua risata, e del suo approccio alla vita.

Lodovica

Much like Diego Latella wrote here (above), my "friendly interaction" with Francesco started with an argument, long, long time ago during (guess what..) a ISODARCO Summer School. It ended, with a lot of chats, talks and jokes in between, in August 2025 in Tuscany during (guess what...) a ISODARCO Summer School), when I had the chance to chat, over breakfast and other moments, with Francesco, smartly and brightly as ever. For my son, Jacopo, who has grown through many ISODARCO Winter Schools, Francesco was "equal to" Winter School and ISODARCO. For Jacopo, Francesco was, along with Carlo Shaerf, simply the embodyment of "Physics".

Thank you Francesco and a big hug, from me and Jacopo.

Being a friend of Anna, we were always very welcome in Rome or Capalbio. We have spend beautiful days and evenings in Capalbio with Francesco and Luisa and their family and friends. Always a lot to talk about, very interesting discussions. We will never forget this. And last
But not least, Francesco was the only Italian who didn’t judge me for having a cappuccino after lunch! We have lost a remarkable man. We will remember him.

Caro Francesco, è stato un vero onore conoscerti. Sono stato davvero fortunato a incontrarti nel mio percorso da studente. Forse sono stato l'ultimo tuoi ultimi tesisti, nella tua lunga e splendida carriera di professore e stimolatore di menti.
Sono onorato di aver potuto imparare da te che cosa significhi fare ricerca, e di averlo appreso da uno dei massimi esponenti della fisica matematica italiana. Inoltre, essere rimasti in contatto in questi anni e aver avuto la possibilità di confrontarmi con te, continuando a imparare dal tuo rigore e dalla tua lucidità, è stato per me sempre prezioso.
Ma, ancora di più, conserverò il ricordo della persona che eri: per me sei stato uno degli ultimi gentiluomini, capace di unire rigore intellettuale, eleganza e umanità.
Ti sono grato per la guida e per l’esempio.

Dear Colleagues, and Bereaved Families of Professor Francesco Calogero,

A one-day conference on Mathematical Physics (ICMP 2016), co‐organized by the Qom University of Technology and the Physics Society of Iran, took place on November 3rd 2016 at Grand Parsia Hotel in Qom; I met Professor Francesco Calogero and talked to him, for the first time, there. In fact, Professor Calogero took part in the conference as both a Scientific Committee Member and a Keynote Speaker.
Professor Francesco Calogero's expertise, openness, generosity, insight, and advice will be much missed by many students and scientists around the world.

Rest in Pease!

Warm regards,
Mahdi KHAJEH SALEHANI
--
Faculty Member in Mathematics
School of Mathematics, Statistics, and Computer Science
College of Science
University of Tehran
salehani@ut.ac.ir
--

I met Francesco in 1995, when I first visited the Physics Department at La Sapienza University to work with Decio Levi (whom I take this opportunity to remember with all my affection) and Orlando Ragnisco, who specifically suggested me to study a very recent article by Francesco. The integrable deformations of the new systems introduced there formed the seed of much of my subsequent scientific activity, so despite not having collaborated directly with Francesco, I am, like so many others, indebted to his impressive work. Since then, I have been fortunate enough to meet him on numerous occasions and to enjoy his scientific and human qualities, his approachability and kindness, which we will greatly miss.

I vividly recall the impression made on me by the lecture Francesco gave in the autumn of 1995 at La Sapienza University about his work on disarmament and the Nobel Peace Prize that had just been awarded to Pugwash. His call for commitment to disarmament, peace, and coexistence among all peoples is more essential than ever, and Francisco will always be a figure of inspiration for everyone. My deepest gratitude.

Inge Kratschmann and Ugo La Malfa. We will Luisa and Francesco in our life and hearth always remember.

I first met Francesco Calogero’s disarming smile more than twenty years ago, in his beautiful house in Rome. Yet, I somehow knew of him already, thanks to the many stories that Sara Lombardo and the other Jedi Knights had shared with me. Given the caliber of the man, I was struck by his hospitality, generosity, and the genuine interest he showed in me, someone whom he had never met before. On that same occasion, I also met Luisa and Anna: it was, without doubt, an extraordinary day!

Francesco and I never talked about mathematics, as I am largely incompetent on the topic, but I later helped with the graphics of the Needs Conferences, of which he was the initiator.
We did share a common passion, though - one that, like true passions, fills you with joy as well as sorrow: La Magica Roma.

One thing I noticed from the very first day was that Francesco always carried at least one pen in his shirt pocket; I cannot remember a single time without it (just check the photos!). This was another small commonality between us: Architects tend to keep a pencil at hand at all times, just in case, for a quick sketch, to capture an idea, or to write a brief note. In a sense, Francesco was an architect too: His task was to design a better world, and while his work remains unfinished, his contribution is immense.

Ciao Francesco, e Grazie.

Il tuo esempio continuerà a insegnarci tanto e a farci luce, in questi tempi bui

I met Francesco only in informal occasions, as the father of my friend Anna and grandfather of Cor and Stella. I had a sense of his worth and work but only today, during the online memorial, I could understand how impressive his work was and the impact that he made on his field of inquiry, his students, his colleagues and the people he met. Il suo impegno per la pace, alongside the rest of his work, is even more impressive. A big hug to Anna, Wigert, Cor and Stella. Spero di vedervi presto ad Amsterdam

I knew Francesco and Luisa, his wife, since 1988, when they hosted me in Roma when I came for an event on nuclear disarmament. Then we met lots of times in Pugwash workshops and conferences, Isodarco and Castiglioncello conferences, and also in Paris where he would stay regularly for his scientific collaborations.

Scientifically, Francesco has been prolific, wrote more than 400 papers, almost half of them as a single author. He was active in science almost until the end. He got important awards and remained humble.

I was privileged to interact with Francesco when he served as a very efficient, rigorous and gentle Pugwash SG (I served in the Council and EC from 1992 to 2002), and after. I learnt a great deal from him on the substance of nuclear issues, and also on how to run such an international organisation, with many issues at stake and diverse views and interests, so that it can function smoothly with a dense agenda and produce lasting results.

Francesco was a model of intellectual and moral integrity, intelligence, dedication and courage. He would never compromise on the principles, would always go to the essential, and knew how to treat unpleasant but unimportant matters lightly with humour. He was also very generous with his time and in constant good mood.

In talking and dealing with people, even in public, he was quite straightforward, this could even be felt as abrupt at times. I felt it when I delivered - trembling - my first Pugwash report at the Pugwash conference in Cambridge in 1989 and he was surprised by its content ! However Francesco would be respectful of everybody and take seriously what his interlocutor would tell him. This feeling of abruptness could not last.

As a Pugwash SG, his competent and balanced mind made him interact with everyone in a neutral way, as objective as one can be. He had a sharp vision for peace and world politics, he would be forceful in presenting his views, however at the same time he was completely open to, and would take into account, differing views.

In a great tandem with Jo Rotblat, Francesco organised many Pugwash workshops on specific topics where outstanding participants would be pleased to come regularly. They edited many policy briefs, memos and books, with novel ideas, still worth reading now.

Francesco and I disagreed on several issues, including political ones, but never has this has been source of the slightest animosity among us. He was "rational" in conducting a group or private discussion : until an argument was proven - or the contrary - , discussion could proceed in a fair and respectful way.

Last but not least, Francesco was instrumental to increase the participation of women in the Pugwash Council and among the invitees to the conferences and workshops. This was not easy given that both Science and World Affairs were - and still are - men dominated fields.

Pugwash, as an organisation, and many Pugwashites individually, have benefited a lot from him. The cause of disarmament also.

In the last years, he did not end his mails with his traditional "Peace", as he was dismayed by the course of world events. Let's hope that the values he cherished will prevail.

the two photos were taken at the Nobel reception in 1995 and on the occasion of a workshop in Poland in 1996.

I first met Francesco in July 1998 when we conducted an oral history interview together. This interview was later published alongside others in the book Fisici italiani del tempo presente (Italian Physicists of the Present Day). Over the years, we had the opportunity to meet occasionally and chat briefly. What I remember most vividly is his voice: very distinctive and charming, a special blend of enthusiasm, confidence, irony and kindness that expressed all the elegance of the great person he was.
He himself gave me this photo at that time, when he had just graduated.

I knew Francesco as Cor and Stella’s nonno. I didn’t get to see him a lot, but I will always remember that he was so kind to everyone, and that he carried such a special kind of energy and warmth.
Stella and Cor had a special bond with him, and he will be missed greatly.
I am sure that they will carry his love and memory with them forever.

Stella, Cor, Anna, ik wens iedereen, maar in het bijzonder jullie, ontzettend veel sterkte toe in deze moeilijke tijd.
Ik zal jullie verhalen over nonno graag nog een keer horen, wanneer het kan ❤️

Grazie a mio marito Giorgio ho avuto accesso alla famiglia Calogero La Malfa che mi ha accolto come una figlia fin dal 1989. Di Francesco non ho strumenti scientifici per ricordarne la grandezza come uomo pubblico, ma come membro della mia famiglia acquisita, posso dire quanto mi abbia sempre colpito la sua modernità e la mente aperta. È’ stato per me, con la moglie Luisa, un esempio di coppia solida, capaci insieme di essere sempre circondati da belle persone. Grazie alla loro ospitalità i miei figli hanno potuto vivere delle estati e dei Natali bellissimi con i loro nipoti Cor e Stella e io mi sono sentita ‘cugina’ della loro figlia Anna senza in realtà esserlo. Ho potuto così costruire una mia individuale amicizia con tutti loro senza dover passare per forza da mio marito, nipote diretto di Francesco.
Dí Francesco e Luisa mi piace in particolare ricordare la loro creatività artistica, che li ha portati a produrre bellissimi quadri e manufatti in ceramica e io sono onorata di poter avere un pezzo di questa loro creatività a casa mia, con un vaso di Luisa e un quadro di Francesco.
Luisa e Francesco sono stati un importante punto di riferimento affettivo per me, e spero che i legami che sono riusciti a favorire fra la mia famiglia e la loro rimarranno sempre saldi.

Con grande affetto per Anna Stella e Cor e ammirazione verso coloro che hanno organizzato questo evento di tributo

I have several vivid memories of Francesco, as I had the luck and privilege to see him regularly over many years. I particularly remember the first time I spoke to him, it was in January 2002 at a research meeting of the Italian integrable systems community. I was in my first year of PhD, and until then, his name had simply been the name attached to one of the most important integrable models I was learning as a student.

Very timidly, I approached him to ask a question about his talk, saying, following the rigid Italian etiquette of the time, "Professor Calogero, potrei farle una domanda?"

He looked at me with his kind smile and said, "Francesco... chiamami Francesco."

I replied, "Va bene, Professore."

And he insisted: "No... Francesco," smiling as if to say he knew that wasn't easy for me.

That exchange made a profound impression on me. On one hand, it made me feel privileged, though even more shy, as I wasn't sure I could find the courage to actually address him by his first name. On the other hand, it was a sign of something that, in time, I learned to be a defining feature of his personality: his supreme interest in humanity and science, in the face of which any barrier of status, age, or power would fall away and become irrelevant.

Ci mancherai Francesco,

Antonio

Caro Francesco,
rimarrà sempre nei nostri cuori la tua intelligenza, la tua ironia, il tuo sorriso e la gratitudine per il tempo condiviso con te e Luisa!
Grazie Francesco.

Unforgettable 1975 Calogero-Tosi handouts on "Mathematical Methods for Physics", rest in peace, see you in Heaven!

We appriciate that our grandchild Max zo cordialy was taken up in your family.Max always spoke so positively about Stella's grand father and mother. We think of you in these sad days.

Most remarkable and special man, fare well.

Thank you, Francesco, for the many things you have given us.

For wonderful and rich models to work on. For your important part in shaping a wonderful research community which is welcoming to newcomers, constructive, not focussing on things that can be measured in numbers but on what is truly valuable in what we doing in our science. Research communities are very much influenced by their leaders - you have been a wonderful such. But also on a personal level - meeting you, talking with you, discussing with you; this has meant a lot for me, has been an inspiration and guidance for my work and for my life.

I feel privileged to have known you - when I think of you what comes to my mind is your friendly smile, encouragement, genuine interest, positive energy, light. I know you were important for many people whose lives you touched. You very much were for me.

Thank you, Francesco.

La scomparsa di Francesco lascia un vuoto profondo nella comunità di quanti hanno affrontato i drammatici temi della pace e della guerra nell'era nucleare. Ma al di là del suo impegno politico così appassionato, mi piace ricordarlo soprattutto per la sua umanità, per il suo senso dell'umorismo, e per la grande umiltà con cui si presentava.

L'ultima volta che l'ho visto era il 2023, quando a Roma Tre avevamo organizzato la proiezione del film "Oppenheimer" alla presenza di Kai Bird e della moglie di Marty Sherwin, Susan. Quando lo ringraziai calorosamente per essere venuto, lui, con gli occhi che gli brillavano, mi disse ammiccando che tra lui e Luisa in due facevano quasi due secoli ..

Pugwash Germany and I myself personally are very saddened to learn that our friend and former Secretary General of Pugwash Francesco Calogero passed away at home in one of the seven hills of Rome, the Aventino which saw so much history. Now Francesco is irretrievably part of history.
He was an admirable Secretary General, efficient, active and coureagous. I met him first in the Eighties discussing non-offensive defense. As a great scientist-statesman and a guardian of Pugwash rules, he became a mentor to me who invited me surprisingly to become a Council member in 2003. We met many times at Pugwash or Amaldi Meetings.
Every one who talked or discussed with him learned quickly about his sharp mind, pacifist believes, scientific dedication, political realism and his commitments for arms control and disarmament. He was a giant of Pugwash, a humble and unemotional custodian of the Pugwash spirit and an friendly human being with standfast moral character.
Pugwash will remember and honor him at the next possible opportunity. We would like to express our severe condolences to his daughter Anna and his family and friends.
As a Secretary General he signed his letters simply with the word PEACE! We will miss him in Pugwash and we will never forget him, but now we have to say very sadly: Francesco REST IN PEACE together with your wife Luisa.
Götz Neuneck, Chair of the Pugwash Council

Deeply sad news. Great human being and scientist,
always friendly to young researchers. Will remember him and what he did.

Integrable Systems in Newcastle - October 2013

I first met Francesco during 1997 NEEDS conference in Kolymbari (I have a nice photo of him playing chess with Martin Kruskal, attached). Since then, I met him at numerous conferences, and he also visited us in Linköping. He was always very friendly, he willingly shared his scientific ideas and also his personal warmth.

Rest in peace, Francesco. Yo will be gratly missed!

I miei primi ricordi di Francesco Calogero risalgono a più di sessanta anni fa, quand'ero studente del Corso di Laurea in Fisica. Mi colpirono subito le sue eccezionali capacità didattiche, l'esposizione chiara e coinvolgente e la sua disponibilità al dialogo per spiegazioni e approfondimenti. Le sue lezioni erano per noi un forte stimolo a migliorare il nostro impegno.

Days have passed since Francesco left, but it is still impossible to believe that he is no longer with us. A great teacher, a wonderful scientist, a kind man. We met many times: at conferences, at La Sapienza, at his home in Rome and at my dacha near Moscow. The last time was at a conference in Bologna, in January 2020, just before the start of covid.
Our discussions with him, both on science and on the surrounding reality, were not always simple. But he had an amazing ability to listen and hear the other person! At the same time, there was also something where he never backed down. This is editing his books and articles!
As a member of the editorial board of TMPh, I am proud that seven articles by Francesco have been published in this journal. But my God, how he defended every letter, every comma in his texts! He himself told me that this is not a problem with our journal only. That other editors are annoying him even more. But he fought back fiercely!
Eternal memory.

Ciao Francesco,
quando mi hai salutato il 18 gennaio ,a conclusione del 64esimo Corso invernale Isodarco, ho percepito che il tuo non era il solito arrivederci ma un addio. Lo sapevi, ma mai avrei immaginato cosi presto. In questi 30 anni ad Andalo, presso il nostro hotel, sei stato un esempio di grande intelligenza, di cordialità. Ti sei sempre posto con estrema gentilezza, sempre disposto ad aiutare e il tuo sorriso ha sempre contraddistinto il tuo essere. Grazie per tutto quello che hai fatto, per il tuo contributo alla fisica, alla pace e grazie per l'uomo che sei stato. Sarai sempre nei nostri cuori.
Luciano, Cinzia, Jacopo e Matteo Toscana

n Memory of Dr, Francesco Calogero


I first heard about Dr. Calogero during my student years from Dr. Vladimir Zakharov, who spoke of him with deep respect, and I had the honor of meeting him at a conference in Kyiv. That was a time of remarkable development in the theory of integrable nonlinear differential equations, a field many leading mathematicians regard as one of the most significant achievements of the past century. This progress was the result of the collaborative efforts of mathematicians from the West, the USSR, and Japan. Dr. Calogero was a brilliant representative of this international community, inspiring and involving young mathematicians in this work, both in Italy and beyond.

But beyond his extraordinary scientific and pedagogical contributions, Dr. Calogero earned our deepest respect for his dedication to promoting peaceful and friendly international relations. I will always remember his warm smile, his gentle and courteous manner of conversation, his thoughtful eyes, and the focused attention he gave to every discussion, whether scientific or political. I remember his visit to Tucson for Vladimir Zakharov’s anniversary conference, our walks during the breaks, and the conversations in which he spoke quietly yet persuasively about the relationship between science and the measures needed to strengthen global stability.

Today, we honor not only the remarkable mind of Dr. Calogero but also the kindness, integrity, and humanity that defined him. I am profoundly grateful to fate for having had the privilege of meeting him on my own life journey.

Professor Calogero was one of the main authors of the magazine where I learned to work. Thanks to him, I discovered the Pugwash movement. I would like to remember him here, together with my dear Director Carlo B.

I met Francesco during the first meeting on Mathematical Physics in Cuernavaca, Morelos, Mexico. These meetings began before 2000 and were held every two years. Various researchers participated, but Francesco was the main scientific organizer. I attended them all, as I live in this city, and these meetings were truly wonderful experiences: few lectures (one or two a day) and constant interaction among the international participants and extensive participation from local students.

From this meeting emerged a long and fruitful collaboration with Francesco, which resulted in 20 publications. During this time, I got to know him better and learned not only to admire him as a scientist but also as a great human being who frequently welcomed us, my wife and me, with generous hospitality, as did Luisa. I learned a great deal from him about science, but also about arms control, Italian politics, soccer, and so much more.

Francesco was undoubtedly an extraordinary person, both as a scientist and as a human being, who left an indelible mark on all of us who had the immense fortune to know him and share time with him. Thank you so much, Francesco. We will miss you.

I met Francesco around 1980. In the following decades our relationship grew as we were both frequent participants at Pugwash seminars, and even more when Francesco became Secretary General in 1989 and I joined the Council in 1992. I had the privilege to stay in touch until recently.
We were all under Jo Rotblat’s guardianship at that time. When the quinquennial conference at Lillehammer (1997) was over and only a few of us were left, Francesco among them, we said to each other that the conference is not over until we have waived Jo goodbye. Two years earlier, Francesco had the honour of accepting the Nobel Peace Prize on behalf of Pugwash, awarded jointly to Pugwash and to Jo personally.
Francesco reserved part of his time for physics and was firm about that. At one point, he said that if others wanted more of him, they should find another SG. I remember the way he said it: straight, honest, convincing and friendly. We could always be sure that he would speak his mind in the spirit of the Pugwash community that he cherished so much. When disagreements emerged and discussions became heated, he could see to it that they were friendly quarrels.
Francesco became a towering figure in the movement, widely respected for his devotion, efficiency, integrity and good judgement. More than that, he was a warm human being. I always enjoyed his company and will miss him sorely.

We met Francesco Calogero during our repeated research visits to La Sapienza University, made possible through a cooperation agreement with the University of Warsaw, facilitated by Francesco and our mentor, Antoni Sym. We had the opportunity to meet a group of outstanding scientists gathered around him, as well as mathematical physicists who came from all over the world. We benefited from Francesco’s aura of cross-border scientific collaboration, which fostered friendships that transcended political views and nationalities—what mattered was science and mutual respect. We valued him at the time as a scientist of remarkable caliber, but only later did we come to realize that he took his public service and his commitment to international cooperation and disarmament just as seriously. Francesco was a warm, open, and generous person. He was a model intellectual and scientist deeply committed to the future of our world.

Jan Cieśliński, Adam Doliwa and Maciej Nieszporski

What a shock. It hit me really hard to hear about Francesco's passing.
He was one of those very special people who leave an indelible mark on everyone who comes into contact with them.
I first met Francesco at the NEEDS conference in Kolymbari, Crete, in 1999. This was my first NEEDS conference, and even today, when I think about it, my heart skips a beat, and an overwhelming nostalgia sets in. I remember that I was quite anxious, not knowing if my work would find any sympathetic ear. After my talk, Francesco stood up and complimented me on my talk, which was what I desperately needed, and then ... asked a question about my thoughts about a system I knew nothing about (the Calogero-Francoise system) and its relation to the Camassa-Holm equation.
It took me two years to answer his question, and at the 2001 NEEDS conference at Cambridge, I gave a short talk about that.

Several years later, I was fortunate to spend some unforgettable time with Francesco in Cuernavaca, Mexico. There was one particular year when we were, for one week, the only visitors with adjacent offices, sharing meals together and enjoying crazy bus and taxi rides from the Institute to our Moshinski's residence. He told me many great stories about his time in the Soviet Union, his encounter with Sir Paul McCartney in Oslo at the Nobel Peace Prize reception, and more. He also completely exposed my ignorance about my countryman, Sir Joseph Rotblat. Thanks to Francesco, I have become a messenger of Rotblat and Francesco's work in the service of disarmament.

Last week, by some strange coincidence, I repeated several stories I heard from Francesco to my colleagues and my family. I am not imagining it. No question, he has left a mark on my life, not only in Mathematics; after all, I spent quite a lot of time working on the Calogero-Francoise model, but he also impressed me as a profoundly great human being. I will miss Francesco for the rest of my days.

With sadness,

Jacek Szmigielski

I had the pleasure of meeting Luisa and Francesco through Anna. Though we hadn’t met before the opened their home to friends of mine that they also had not met. This unprecedented generosity is something that over the next couple of decades I would enjoy. We celebrated holidays and birthdays together in Amsterdam. Enjoyed lunches and dinners in Rome, museum and botanical garden tours in Brooklyn and debated politics in Capabio.
Francesco always with a humor, humanistic and humble. It was an honor and enrichment to my life to have known him. Thank you Francesco, you both will always be in my heart

It is a very sad momemt! France3sco was not only distinguished scientist with many important contributioons to several different fiels of physics. He was also a very kind and generous man!
He will be missed by many colleagues and by his numerous pupils.
My sincere condolencies to his family and pupils!
Vladimir Gerdjikov, Sofia, Bulgaria

E’ molto difficile esprimere le sensazioni che ho provato alla notizia della scomparsa di Francesco. Per me che lo conoscevo da quasi quarantacinque anni è stato come riavvolgere, in un attimo, un nastro in cui sono contenuti i ricordi di una vita. Ho conosciuto Anna, io allora ventenne, nell’ormai lontano 1982 e con Francesco, così come con Luisa, il legame è stato sempre fortissimo. Il profondo affetto che nutro non mi consente quindi un’analisi lucida della persona. Dovrei operare una sorta di distacco razionale ma sinceramente proprio non ce la faccio. Preferisco ricordare Francesco semplicemente per la sua dolcezza, per il suo essere uomo mite ma sempre determinato, per la sua straordinaria dimensione di uomo di scienze e di insegnamento, per il suo immenso patrimonio di conoscenza mai ostentata e, al tempo stesso, per la bella semplicità della persona che era. In una parola, per la sua grande umanità da cui ho avuto la fortuna di imparare molto.
Ciao Francesco, mi mancherai tanto!

I join all here in mourning the passing of Francesco Calogero--a first-class physicist, deep thinker about world affairs, exceptional Pugwash leader, and dear friend and mentor to so many of us.

Francesco and I were the closest of colleagues during the third of a century when I was most active in Pugwash, above all in the years when he was Secretary General and I was the head of the US Pugwash Group and Chair of the Executive Committee of the Pugwash Council.

In the last 15 years, though, I had seen him only a couple of times. I was grateful to be invited by Carlo Schaerf, Steve Miller, and Francesca Giovannini to speak at this year's ISODARCO seminar in Andalo--my first time at ISODARCO--for many reasons, not least for the opportunity to some old friends from Pugwash once again. I was hoping Francesco would decide to come up from Rome in spite of his failing health, and I will be forever grateful that he did.

He sat with me, my wife Cheri (who, like me, had known him since 1973), and our grown daughter Jill at a number of the breakfasts, lunches, and dinners at the seminar, and he and I sat together in the front row and kibitzed at nearly every session over the course of the seminar.

During the mid-day break on the second-to-last day of the meeting, Francesco and I were visited at the conference hotel by the Executive Director of the Lindau Nobel Laureate Meetings, Nikolaus Turner, and a German photojournalist who works with the Lindau group, Peter Badge. They had traveled from Lindau to talk with us about the Pugwash Nobel Peace Prize ceremony in Oslo in 1995 and to recruit the two of us to the Founder's Assembly of the Lindau meetings. (As older Pugwashites may recall, Francesco and I had shared the stage in Oslo with Joseph Rotblat, co-winner of the Prize in his own right; I followed Jo at the podium to give the acceptance speech on behalf of the Pugwash organization, and Francesco accepted Pugwash's medal from the King.)

I tell this story to explain the two photos you can find at this link: https://drive.google.com/drive/folders/1bfx504U4D-MF3EefafaXh2riLwkyWLdp?usp=sharing. They were taken by Peter Badge on January 16, and they must be among the last photos taken of Francesco before his passing. One is of Francesco and me with Nikolaus Turner; the other shows Francesco signing the agreement to join the Founder's Assembly of the Lindau Nobel Laureate Meetings.

As has already been abundantly noted on this Memory Wall, the world has lost a great scientist-statesman, and many of us have lost a dear friend. He will be sorely missed, and none of us who knew him will ever forget him.

In ricordo di Francesco Calogero e a complemento a quanto di più completo e vissuto è stato scritto e detto in questa triste circostanza da parte degli amici di Francesco di tutta la vita , posso solo aggiungere- se qualcuno non lo ha già fatto-che egli fu anche ispiratore, firmatario e probabilmente redattore della lettera aperta/appello intitolata “Per un mondo senza armi nucleari”, pubblicata dal Corriere della Sera nel 2008 in cui alcune eminenti personalità politiche (appartenenti a schieramenti politici diversi)e scientifiche italiane si espressero a favore del disarmo nucleare. Oltre a Francesco la sottoscrissero: Massimo D’Alema, Gianfranco Fini (allora presidente della Camera)Giorgio La Malfa e Arturo Parisi.
In un momento storico, purtroppo di breve durata, in cui una riduzione ed eventuale eliminazione delle armi nucleari appariva quasi a portata di mano, i “5 politici e scienziati” italiani si unirono ai “4 cavalieri” americani (Kissinger, Nunn, Perry e Schultz) nel richiamare l’attenzione internazionale sulla necessità di un mondo senza armi nucleari. Tali iniziative dettero origine alla formazione a Londra del think tank “European Leadership Network” del cui gruppo italiano i 5 citati “cavalieri italiani ”formarono il primo “nocciolo duro”.
Un ulteriore titolo di merito che si aggiunge ai molti altri evocati in memoria del nostro comune amico scomparso.

Carlo Trezza

Sono veramente addolorato per la perdita di un grande uomo di pace e di scienza con il quale ho condiviso momenti di vita di vario genere.
Conobbi Francesco Calogero, di cui mi onoro di averlo avuto come amico e compagno nell'USPID, negli anni '60 all'Istituto di Fisica dell'Università La Sapienza come mio professore di Fisica Teorica. Fummo poi rivali nelle partite di calcio: Francesco "ala veloce" della squadra "Professori", io "ala meno veloce" della squadra "Spazio". E poi ci ritrovammo come soci dell'USPID.
Quanti bei momenti di serenità e di scambi di idee durante i numerosi incontri di Castiglioncello. Quanti pranzi e cene consumati assieme in piacevole conversazione sempre illuminata dalla sua saggezza e fondamentale bontà.
Grazie di cuore Francesco per la tua fondamentale attività in favore della pace anche in Pugwash, quando come Segretario Generale del "Pugwash Conferences on Science and World Affairs" ritirasti il Premio Nobel per la Pace il 10 Dicembre 1995, assegnato a Pugwash e a Josep Rotblat.

Caro Francesco ci mancherà la tua voce saggia in favore della Pace. Riposa in pace,
Franco

Come segretario nazionale dell'Unione Scienziati per il Disarmo ho un grande debito di riconoscenza nei confronti di Francesco, per aver contribuito a creare l'associazione e ad averla mantenuta attiva e vivace per tutti questi anni.

La sua voce autorevole, la sua assoluta lucidita' e precisione scientifica erano risorse insostituibili per le nostre attivita' e ci mancherenno moltissimo.

Non avevamo sempre la stessa opinione, ma il confronto dialettico, anche acceso, ha permesso a tutti di capire meglio, di vedere oltre, di guadagnare una comprensione ultieriore degli argomenti.

Tutto l'USPID e' rimasto colpito dalla notizia della scomparsa di Francesco e gli si stringe attorno con un grande abbraccio.

Francesco Forti
Segretario Nazionale USPID

Professor Francesco Calogero was a longtime friend of China's nuclear disarmament community. He made significant efforts to encourage Chinese nuclear scientists to participate in international nuclear disarmament exchanges. My Chinese colleagues and I all miss him dearly.

Very sad news.
Francesco was a great friend. I met him at the fantastic meetings organized by Pierre Sabatier in Montpelier in the late 1970's
and I remember him and Tony Degasperi with warmth and affection.
He was at the center of a great moment in Math-Physics where lots
of strands came together.
Sorry that I cannot be there and best regards to so many friends that we shared over the years.

Caro Francesco avevo visto una tua intervista tempo fa sul tema del riarmo nucleare. Mi auguro tu abbia potuto avere una morte serena. Conservo ancora diverse edizioni della rivista Pugwash che mi avevi regalato. Uomo di scienza che coltivava l'etica della pace con animo gentile. Per me, tu e Luisa eravate una cosa sola. Vi porto con me.

Francesco Calogero is one of the pillars of peace and disarmament movements and associations, such as Pugwash, the International School On Disarmament And Research On Conflicts (ISODARCO) and the Union of Scientists For Disarmament (USPID).

He was a person of great intellectual honesty, great scientific competence and rigor, and great openness to the ideas and opinions of others.

He leaves an unfillable void for all of us and for future generations who care about Arms Control, Disarmament, and Peace.

I met Francesco in the context of activities organized by USPID first and then ISODARCO. I was always struck by his rigor in evaluating the points of view of others and his willingness to accept them when they were well documented.

I remember when, following a seminar I gave as part of an ISODARCO course in which I questioned the effectiveness of a missile defense system during a Gulf War and criticized certain technical aspects of the IT subsystem in particular, Francesco reprimanded me rather harshly, arguing that what I was saying was very serious and that I should have backed it up with appropriate bibliographical references, which I had omitted to cite so as not to weigh down the seminar too much.

We did not know each other very well yet: I was just a young researcher of the Italian Research Council, little more than a new hire.

I was very upset and we began to argue. I explained the reason for the omission and provided him with the reference bibliography (articles published in international scientific journals and official reports).

Francesco immediately changed his attitude, to the point that, together with the other members of the USPID Scientific Council, he approved an official document on the subject produced by myself in collaboration with a colleague from USPID.

Since then, Francesco has listened with great interest to my considerations on the (un)reliability of digital systems and, more recently, has greatly appreciated the work that we, together with colleagues from USPID and ISODARCO, have carried out in the field of military uses of AI.

Diego

Ciao Francesco, we will miss you, for ever.

We will miss our visits to you and Luisa at the Aventino or in Capalbio. We will miss the possibility to remember our Cuernavaca memories together. Our discussions about maths, physics, science or geopolitics and your comment and wisdom on the current world affairs. We will miss your sense of humour, your voice and your beautiful and reassuring smile.
But in this moment of sorrow, we would like to thank you for every minute that you have spent with us: it has been a privilege and an honour. You have been a role model, a mentor, an intellectual of the finest calibre – we have learned so much from you! - but above all you have been a very dear friend, curious and supportive. You have touched our lives and the lives of many generations.

Grazie, Francesco! For ever.

David, Matteo & Sara – your Jedi Knights

Ricordo Francesco per la sua profonda umanità e gentilezza, unite a una determinazione sincera e mai ostentata. I suoi consigli puntuali sulla campagna Senzatomica hanno rappresentato per me un riferimento fondamentale, espressione di un impegno autentico, guidato da rigore intellettuale, umiltà e responsabilità civile.

Seven years ago I met Anna Calogero in Amsterdam and of course I fell deeply in love with her. Fortunately this feeling was mutual and so that summer I had the chance to meet her parents in Capalbio. I was welcomed with open arms by Luisa and Francesco, who both insisted that I would call them by their first names.
At that time Francesco still spent a lot of time at his desk in the middle of the living room writing pages and pages of mysterious formulas. From time to time he joined in the conversation, preferably to make a joke or have a good laugh and someone else’s. After these brief interruptions he would go straight back to this other universe of numbers, equations and formulas.
I’ve always admired this capability to exist in two realities on very different levels at the same time. Maybe this is quite normal for a physicist, but to me this was very special.
I remember him as a bright, kind and open person. He would gladly tell me about his life and showed genuine interest in mine. I understood that he worked at the highest level in science and in matters of disarmament. At the same time I watched him studying things like corkscrews or pepper mills with fascination. When I could sometimes help him by repairing a stapler, he would be very thankful and would even show some kind of admiration.
I know that his work involved the entire world and probably even the universe. I’m very grateful that I had the chance to meet him on a smaller scale in Rome, Capalbio and Amsterdam. To me he was first and foremost the father of the love of my life. I will certainly miss him for his wisdom, his kindness and his open-mindedness.
On the day of my father’s funeral we heard about the passing of Anna’s father. Having previously lost our mothers, this makes us orphans and also the next senior generation. We will try to follow the example of our parents on our own scale.

Wigert Dronkert