Nogradi, Daniel

I attended the “Strong Dynamics Beyond the Standard Model” workshop in the summer of 2010 in Aspen. The workshop allowed me to interact with colleagues working on similar and more distant fields from my own, people with whom I would otherwise have emailed/skyped/phoned only. Being physically at the same location for an extended period (three weeks for the workshop I attended) was very helpful and allowed for the exchange of ideas which would otherwise be very cumbersome or slow. All in all I have benefited greatly from my stay at the Aspen Center for Physics.

Nelson, Philip

I first attended an Aspen session as a postdoc in 1986. At that impressionable age I formed a reflexive response to Aspen as a place where I could focus completely on science, and every time I have returned something very good has happened in my scientific life.

For example, I remember a single conversation with Greg Moore and Adrian Ocneanu that lasted over eight hours. That sort of intense experience could never have happened back at home, what with one real–life imperative or another. There was a meal in there somewhere, but afterwards I had absolutely no recollection of what I ate. I did, however, know exactly what I wanted to work on next.

Fast–forwarding to this century, I came to Aspen last summer with a steaming heap of ideas for a book that I wanted to write, and a lot of scattered notes and memos. I am absolutely convinced that had I stayed home, I would never have managed to wrap my head all around the many potential story elements. There is a threshold of intensity, below which one's thoughts remain permanently scattered despite repeated attempts to rearrange them. But a couple of weeks in Aspen sufficed to get a real storyline, dense with interconnections. Equally important, I managed to identify all the beautiful threads that didn't fit that particular 500–page story and push them into the Some–Other–Time box. I cannot describe the resulting sense of release, though every author knows it. The road remains long, but now I can see its beginning, middle and end.

Couldn't I have instead gone to some monastery and done this? No, it was essential that I was surrounded by experts who could discuss ideas with me, point out the key experiments in each topic, and so on.

Plummer, Mark A.

First and foremost, I would like to say that attending a 2010 workshop in molecular physics, “New Perspectives in Strongly Correlated Electrostatics in Soft Matter,” was one of the most intellectually stimulating events in my career. Aspen and the ACP is a very lovely place to work and the people in attendance are very helpful in stimulating new ideas.

I am a computational physicist/chemist determining the relationships between molecular structures and molecular properties. Recently, I have been developing a new mathematical technique to more quickly determine the physics of protein folding. My recent publication was on the folding of hydrogenases into their tertiary state which affects the level of hydrogen production from water. I continued this work at the 2010 summer workshop where I was able to cut the error between the actual and computed tertiary structures in about half. After the workshop, the mathematical technique was used in a NSF–sponsored effort that found a hydrogenase mutant that produces hydrogen at a rate of 400 times that obtained in nature. Previous to this finding the best hydrogenase mutant could only produce hydrogen at four times that via the wild type found in nature.

Also at this workshop, I was able to assist my office mate by suggesting a computational technique to study the shape of thin film membranes under stress. This probably resulted via the ACP policy of having office mates being in different workshops.

Lastly, congratulations ACP on 50 years of successfully providing a stimulating work place and people where new ideas can flourish.

Pollet, Lode

Although still being a young researcher (32 years old, first year Associate Professor), I have the best possible memories of the Aspen Center for Physics. I have had the privilege of being able to come several times during summers to Aspen. It is a place where I have been able to work quietly on some of my best known papers, while at the same time the Aspen Center created a stimulating scientific environment for me to explore new horizons. The beauty of Colorado's wilderness allowed me to make great relaxing excursions on the weekends. The Aspen Center provides for me an ideal forum to focus on research, while enjoying a high quality of life. I congratulate the Center on its 50 years, and am looking forward to the next 50 years.

Prince, Tom

Tom Prince invites you to view his Aspen photographic impressions here.

Putman, Mary

One of the moments that stands out in my mind is drawing the distribution of gas in the Local Group on a blackboard for a group of astronomers. This was an interesting step in terms of thinking about the Local Group gas (both in and beyond the galaxies) as an interconnected phenomenon. Several of my papers since that meeting have discussed the connection between the gaseous components.

Radin, Charles

For me the genius of the Aspen Center workshops is an environment in which you can identify something intriguing, and then have sufficient time to think it over, go back for a correction, and repeat, and repeat, over a period of weeks until you have actually connected to something wholly new to you! Ordinary conferences and workshops are successful for picking up ideas close to what you already know, something you can absorb quickly, but the Aspen Center can facilitate a leap into a distant research area. This happened to me, precipitated by some offhand remarks by Randy Kamien at a workshop in 2004, which shifted my focus ever since. The atmosphere at ACP is also incredibly congenial, in large part due to Jane Kelly and the other staff, making it not just a center for creativity, but a truly enjoyable one. I return whenever I can!

Reuter, Juergen

It is really a great and lovely atmosphere there, and especially the policy of having these joint offices with one other person makes personal contact and discussions very easy. I did a substantial amount of work there in Aspen; I for sure learned a lot and had most of the interesting discussions up to now there. Many contacts to scientists important for my research (and not to forget for my career) I made during my stays in Aspen. In fact I met some of the senior scientists with whom I started some of my most successful projects there in Aspen. Those people later on wrote letters of reference for me for faculty positions, so I could really even say that the Aspen workshops helped me substantially in finding a permanent job in research. But I think most importantly, it helps defining new directions in research as I experienced it several times that discussions started there led to workshops and new ideas and directions in research. I wish you all the best and hope for another half a century of Aspen workshops!

Rich, R. Michael

My first experience with the Aspen Center for Physics was attending a summer workshop on galaxy formation, where I was able to have one–on–one discussions concerning the Galactic bulge with Jim Peebles. The Aspen format is unique; over the years, I would grow to appreciate the decision to limit power–point slides, which produce the mind–numbing experience that often characterizes the intensity of the typical meeting scenario. Organizing the 2011 meeting on the Galactic Bulge was one of the high points of my career. The three weeks of intense discussions led to interplay between theorists and observers. Held at a critical time, when our team's Bulge Radial Velocity Assay data had just become public, along with the two other major bulge surveys, the meeting energized the whole subject area. While time will tell, already several significant papers have resulted from that meeting. The meeting also renewed and deepened an old friendship and led to many new ones, something that rarely happens in the larger, more hurried formats of today. I can say now what I did not appreciate as a young faculty member: there is no meeting place or experience in the world like Aspen. The bucolic setting of the summer workshop, a field punctuated by aspens and crisscrossed by streams– is unmatched, resting the soul and inspiring the mind.

Salamon, Peter

The wonderful workshops I attended as a graduate student at the Aspen Center for Physics inspired me to start Telluride Science Research Center.

Schwarz, Dominik J.

To me and my collaborators the ACP provided a marvelous atmosphere to identify several large angle anomalies in the microwave sky. We enjoyed the anomalous mix of recreation and work together with our families and I'll be happy to come back to the ACP in the future.

Schmidt, Brian

I first came to the ACP in 1992 as a finishing graduate student under Bob Kirshner to discuss the Hubble constant. There I met Jim Peebles for the first time, but also renewed my acquaintance with Jeremy Mould – a meeting which eventually lead to me moving to Australia. I next returned in 1996 to tell the community about the High–Z SN Search, our plan to measure the 'deceleration of the Cosmos.' I remember hard questions about how the supernova might be changing, but a keen interest in our work. After 1998, the High–Z team used Aspen several times as a place to jointly work on refining our measurement of Cosmic acceleration, and the Essence program was born out of one of these get togethers in 2001. I celebrated my 40th birthday with the 20th Birthday of SN 1987A in 2007 at the ACP. The ACP has been the place I have gone to expand my horizons for the entirety of my career.

Sethi, Savdeep

I have extremely fond memories of my time at Aspen. Some of my closest friendships and collaborations were formed during those trips. Clean living with just a bicycle combined with the informal setting for discussion makes for a truly wonderful experience. It is hard for me to do justice to those experiences with words. On one occasion, I remember contemplating flux in string theory while absorbing the beauty of the mountains. On another visit, pondering triples with a wonderful set of collaborators. The origin of space-time and the structure of null singularities were the focus of another trip to the center. The discussion of physics is wonderfully complemented by the shared experience of hiking and biking on the weekends. I truly treasure those visits which served to both stimulate thought while rejuvenating the spirit.

Shadmi, Yael

“This is heaven!” I thought, when I saw the ACP for the first time back in 1996. This is what I always tell people when they ask me what the ACP is like. It has often occurred to me that the ACP is remarkably similar to the Jewish version of paradise–a big, beautiful garden with people sitting and studying, minus, fortunately, two elements: the feasting on mythological beasts, and the fact that presumably, as a woman I wouldn't be allowed entrance...

The first time I visited Aspen, I was a postdoc at Fermilab. The next time I visited, I was already back in Israel, and brought my 11–month old son, Michael, along. He got altitude sickness on the way from the Denver airport, as he continued to do on every single visit until he was nine and passed the torch to his twin brothers, which culminated in an eventful stay at the Aspen Hospital. Why does a mother subject her kids to such misery? First, because we all loved it, after the first few miserable days were over. But most importantly, because it was so valuable for me, precisely because I was away from the Center, in Israel. The ACP provided me with the rare opportunity to meet so many of the people working in my field in the same place, at the same time. The fact that it's all happening in Aspen, which is so kid–friendly, is a real added bonus. I didn't have to leave my family and do a lot of travelling to meet all these people.

The quality of the interaction at the ACP is entirely unique. It's not like coming to visit some university, where the hosts are busy with their everyday chores like teaching and committee work, and it's not like a conference, with a schedule packed with talks. At the ACP, everyone has time to talk about physics, and people collaborating on the same projects are completely free to do that. Some of my most enjoyable physics discussions and collaborations took place on the benches outside, or in the different alcoves inside.

I admire the people who conceived the idea of the ACP, the people who designed the beautiful, simple, and immensely pleasant buildings, and the staff who continue to make it feel like a second home. I think this is really one of the secrets to the ACP's huge success and effectiveness: you come back, you meet all the ACP people, and you feel like you've never left.

Shrock, Robert

I have found my stays at the Aspen Center for Physics to be very valuable for my research and for the opportunity to learn about other people's research. This Center plays an extremely important role in bringing together physicists from different universities and laboratories in an atmosphere where they can discuss informally and work intensively on research projects. For example, my first visit to Aspen, in July, 1979, enabled me to collaborate with MikhailVoloshin, then at ITEP, on a paper giving constraints on CKM mixing angles, published as R. E. Shrock and M. B. Voloshin, "Bounds on Quark Mixing Angles from the Decay K_L \to \mu\bar\mu," Phys. Lett. 87B, 375 (1980). Subsequent visits have been equally fruitful. These have made possible valuable collaborative work with Prof. Tom Appelquist from Yale on dynamical models of electroweak symmetry breaking and have contributed directly to two papers, namely T. Appelquist, M. Piai, and R. Shrock, "Fermion Masses and Mixing in Extended Technicolor Models," Phys. Rev. D 69, 015002 (2004), hep-ph/0308061, and T. Appelquist, N. D. Christensen, M. Piai, and R. Shrock, "Flavor-Changing Processes in Extended Technicolor," Phys. Rev. D 70, 093010 (2004), hep-ph/0409035. I am very grateful to the Aspen Center forPhysics for these opportunities to learn more and work on research papers.

Sommerfield, Charles

This is a nostalgic look at Aspen and the Physics Center five decades ago.

As I was walking along a hallway in the physics building at Brandeis University about 50 years ago I saw a notice on a bulletin board inviting applications to a brand new summer institute in theoretical physics. I returned to Yale with the news and Randy Durand's eyes lit up.

Aspen today is probably as different from the Aspen of 50 years ago as that Aspen was from the old mining town. In 1962 only Route 82 and a few streets downtown were paved and Route 82 itself became a gravel road just a few miles east of town on its way to Independence Pass. Tanker trucks would rumble through the city each morning spraying water on the unpaved surfaces and on any passing pedestrians.

The Physics Division of the Aspen Center for Humanistic Studies, as it was officially known, was housed in what is now Stranahan Hall. There were about 12 offices, each holding two people. The secretary was just inside the entrance and there was a small library in the storage area at one end. A volleyball court behind the building afforded exercise most afternoons. I found it desirable to have an office facing the music tent, since if the wind was blowing from the right direction one could hear the music wafting from rehearsals of the festival. In the tent itself (since rebuilt), a strong wind would sometimes cause the whole structure to sway very unstably, usually with an accompanying roar that could overwhelm the concert.

We were housed in some of Aspen's distinguished homes. In 1962 I shared the R. O. Anderson house on W. Smuggler Ave. and N. Second St.---which was at that time painted a brilliant red--- with Jerry Percus and Kurt Symanzik. In 1963 I was with Curt Callen in a modern house at the base of Red Mountain and in 1968 I was one of the residents in the Firestone House on W. Hallam Ave. It was in the latter that I awoke early one Sunday morning to a loud bleating noise and observed a large flock of sheep being led through the town by a shepherd and his skillful dogs.

The music school was then located right in the heart of the city. The music students would also sometimes be in evidence at the occasional physics parties, to which all the participants were generally invited. We could attend lectures at the Institute for Humanistic Studies. I specifically remember one by Howard Head, of the eponymous ski company, telling us that it was important to know how to meet a payroll, and another by Walt Rostow at which there were some rather hostile questions from the audience and equally hostile responses from the speaker. We were also invited to some of the receptions at the Institute where we could meet the Executive Seminar participants. I recall a somewhat argumentative conversation with Paul Goodman but I can't remember what we spoke about.

There were no workshops. The physics program was very unstructured, with usually only a single weekly seminar. At least for the bachelors like me the work week was seven days, but a hike might be arranged at any time that the weather appeared promising. The weekly picnics were held all over the area.

One hears that Aspen is very expensive. This statement seems to be invariant under time translation. It was true in 1962 and it is true today. I do remember passing up the chance in 1963 to buy a lot in the center of town (on which a hotel was later built) for the staggering sum – at least to me – of $30,000.

Lastly I would like to point out that the most important work I did in my many summers at Aspen took place on a very rainy Sunday in 1975 when I was forced to stay in my rented condo while surrounded by my family.

Sundrum, Raman

I am very pleased to relate how profoundly my visits to the ACP have inspired and enriched the direction and substance of my research and career in theoretical particle physics.

In the early 2000's, soon after the original "Randall-Sundrum" (RS) model came out as a solution to the Hierarchy Problem, I was engaged in trying to turn it into a comprehensive framework for experimentally accessible particle physics. This was a very challenging program, trying to integrate our understanding of electroweak precision tests, grand unification, flavor physics, neutrinos, and so on. I was fortunate to have participated in an ACP summer program at this time, bringing me in contact with several of the world experts also engaged in aspects of this program. The Center gave us the opportunity to really test out, criticize and flesh out half-formed ideas, as well as to brain-storm on new possibilities and review developments in related topics. In particular, I would attribute three important benefits to me of this stay: (i) It greatly improved the technical substance of the paper that my collaborators and I later wrote on "RS1, Custodial Isospin and precision tests". (ii) Even more importantly, the deep interactions I had at Aspen sharpened for me the central issues that defined the next decade of my research in this direction. (iii) At Aspen, I had the first intense discussions of a recent "crazy idea" by Gherghetta and Pomarol on the phenomenological viability and attractiveness of the strong-coupling mechanism of "accidental" supersymmetry, rendered in RS form via AdS/CFT duality. While our discussions led to finding some technical objections, the idea resonated greatly with me, and I took home from Aspen the goal of working through the technical issues and adding substantively to the original idea. This took me several years to complete, resulting in my 2009 paper, "SUSY Splits, But Then Returns."

More recently, I was a co-organizer of the "Year One of the LHC" Aspen 2011 summer workshop, at a pivotal time for particle physics in general, as well as for my own efforts to align my theoretical research and understanding more closely with the experimental program of the CERN Large Hadron Collider. At Aspen, we were able to gather a diverse group of theorists and LHC experimentalists and to begin to consider very early LHC data, as well as data from the Tevatron. This group shared very strong common interests but brought very complementary strengths. We had significant discussions about the Tevatron top quark anomaly (still a mystery) as well as wide-ranging discussions about the way forward at the LHC. This was a time in which the experimentalists were able to learn the latest ideas and judgment calls from theory, and theorists were able to learn from the experimentalists the latest techniques and opportunities for the future. It was a special time of equilibration between the two halves of the subject, brought together by the urgency of exploiting the full potential of the LHC. One output of these discussions was the focus on testing the central elements of how weak scale supersymmetry (already under assault from LHC data) solves the hierarchy problem, namely the stop/sbottom/gluino subsector. Several of us, theorists and experimentalists at that workshop, subsequently wrote papers on this subject and helped push the hunt for third generation superpartners as a major enterprise for the LHC in 2012. For me, it was hugely encouraging to see that this subject resonated between the theorists and experimentalists at Aspen, and it made clear to me that the subject "had legs," posing a highly motivated set of challenges and goals for the experimental program. I continue to work on it.

Personally, I was fortunate to have been able to meet a very resourceful, aggressive and knowledgeable group of experimentalists at the workshop, now a very important addition to my "network." Two of my co-organizers, Patrick Meade and Michele Papucci, and I were so inspired by this workshop, and in particular by Aspen discussions with CMS experimentalist Sanjay Padhi and others, that we conceived of a uniquely structured LHC workshop, combining Aspen-type emphasis on wide-ranging discussion among hand-picked participants, with a large conference format that allowed coverage of all major issues. This conference, "Supersymmetry, Exotics And Reaction to Confronting the Higgs" (SEARCH), was put together after we dispersed from Aspen, with cooperation from many theorists and the LHC experiments, and was held at the University of Maryland in March 2012. It was quite a success and we received many words of appreciation. It would not have happened but for the Aspen Center and the time and company it provided to reflect on the deepest needs of the field in the LHC era. In my own career, the Aspen workshop and its spin-off of the SEARCH conference, "retrained" me, and gave me a much greater sense of my own role as a theorist working hand-in-hand with the experimental effort.

Finally, I would like to emphasize how unique ACP is in allowing the kinds of developments I reported above. The mind-altering beauty of the mountains, and the Center itself, combine with the largely unscripted time and high quality of physicists chosen from a range of sub-disciplines, to allow one to really delve into our subject. I often go to workshops at other venues and think to myself, "boring." At the better ones, I think to myself, "I really learned something here." After each of my visits to the Aspen Center I have returned thinking, "I am changed, I have a new direction."

Suntzeff, Nicholas

The ACP has had a big impact on my science and that of dark energy. I was just at the Nobel Prize festivities, and during the lectures, photos of the meeting of the HZT were shown in Adam Riess's talk. As Adam said, we tended to meet in Aspen (at the ACP). You can go the Nobel site, download Adam's talk, and see the photos of Aspen. You can also see the famous photo of Brian and Saul fighting in front of the outdoor blackboard. I had just finished my talk, and we were breaking up, and since both teams were there, I asked the two to pose. It is now an iconic picture – and in a humorous way it shows the spirit of Aspen.

There are two important events I can remember. I am sorry I don't remember the precise dates. Both have something in common. How do you decide how to measure progress on something that has vague scientific goals? You can beat down errors by sqrt(N) statistics, but this is rather brutish.

1. When we were first deciding on the goals of the Large Synoptic Survey Telescope, we had a series of lectures and debates about how to measure success – a metric to measure progress in dark energy, and a Figure of Merit (FoM) for the LSST. Tony led the discussion on how to create a FoM for the LSST and the debate lasted for days. We finally adopted one, which became the basis for the FoM for the telescope project. I would also say that in the FoM discussions, we debated the scientific and technical specs for the telescope. One discussion in particular led to push to make the photometric accuracy of the LSST much higher, so that we could do photo–z's with much great precision. I believe this single discussion more than anything has deepened the range of LSST science.

2. After the discovery of dark energy, around 2000, our HZT wanted to think of what to do next. It was at Aspen, with those discussions, that we decided our future course for our dark energy research. We divided the project up into two pieces. The first was to break off the piece to measure the Hubble flow at z>1 and the other was to pin down with much more precision the value of w. The former became the Higher–Z group which Adam eventually led and was an HST project, and the latter became ESSENCE. Both projects had major impacts on the understanding of dark energy. The topic of discussion really was how to measure reddening in Type Ia's. This is still a somewhat unsolved topic, but we made real progress at Aspen on different ways to attack the problem. In summary, I would say that the ACP provided us a unique place to discuss in freeform the future of our dark–energy research.

Trodden, Mark

I first attended the ACP as a young postdoc. What struck me most was the informal atmosphere, which allowed for more frequent interactions with senior faculty than I had been used to. I learned a lot during that visit, and discussed interesting ideas with new people, who later were to hire me as a postdoc partly on the basis of those discussions. Since then I have visited quite a few times, always enjoyable, and a few years ago I helped run a program, and participated in a public event at the opera house. I have fond memories of all this, but the primary thing I would like to say is that my visits to the ACP have helped me to do better science.

Vachaspati, Tanmay

I have participated in Aspen workshops a few times, and have enjoyed them immensely. I also co-organized a program on cosmic magnetic fields that I feel has fueled a lot of interest in the subject, as it has grown quite a bit since then. The Aspen Center is perfect for getting together a group of people to discuss a topic that is still in its nascent stages because the relaxed schedule, the music under the tent, the hikes, the picnics, the bicycles, are all very conducive to informal and friendly exchanges. Once in a while I have also attended Aspen as a "solo" participant, not particularly attached to any program. On these occasions, I have been able to focus on my own projects, away from all distractions.

Valle, JWF (Jose)

I was only twice at ACP, first in 1987; my host was Lincoln Wolfenstein. That was a very enjoyable stay indeed. On that occasion I remember the fruitful discussions with Lincoln which led me to suggest the idea of non–standard–interaction–driven neutrino conversions based on my previous work on the seesaw mechanism with Joe Schechter and Rabi Mohapatra. Discussions with James Wilson from Lawrence Livermore were very inspiring indeed, and led me to suggest the important non–standard interactions in the propagation of supernova neutrino. This topic was subsequently explored in a number of papers and constitutes today part of the agenda for new long baseline neutrino oscillation experiments.

My second visit at ACP was 20 years later as a co–organizer of the neutrino physics program. This time I hosted many colleagues in the field and I also remember many fruitful discussions with several of them which materialized in publications, whose importance is still a bit early to assess.

What was remarkable on both occasions was the nice and stimulating atmosphere provided at Aspen.

Vishveshwara, Smitha

Time and again, perhaps after a mundane day of toil or errands, I close my eyes and invoke a vision that brings a smile. A long road flanked by aspen trees of shimmering green-grey foliage descending into beauteous vales and rising to pristine mountaintops. Leading to an idyllic sanctuary where scholars abandon their cares, explore in solitude, or more often, in one another’s company, where new ideas brew and old ones take flight. Where streams meander, verdant meadows border awe-inspiring peaks and music of the finest timber wafts from the tent next door. Where caring angels – Jane, Patty, Paula and so many others,-- keep the place alive. Where each week children’s laughter echoes, castaway liquid nitrogen hisses and bubbles in a brook, and smoky fragrances emanate from a grill. Where warm, lasting collaborations and friendships form at a chalkboard, by a hearth or over one or several glasses of wine. What a blessing that for five decades, time and again, this vision has become a reality for so many of us at the Aspen Center for Physics!

Vollhardt, Dieter

I still remember my first stay at the Aspen Center for Physics in the summer of 1981 as if it were today. I was a young postdoc participating in a summer program on “Localization and Interactions in Impure Metals” which was organized by Elihu Abrahams and Patrick Lee. The personal encounter with many icons of theoretical physics impressed me deeply. I was given the opportunity to present the results of Peter Woelfle's and my work on the theory of Anderson localization during one of the blackboard talks on the patio. To stand in front of all those famous experts sitting in the audience was a somewhat intimidating experience. (I also felt hot for another reason: in those days the roof over the patio covered only the audience while the speaker was exposed to the elements, in my case the sun...) Nevertheless my presentation was very well received and led to many discussions. As a result Elihu invited me to prolong my stay at the ACP; Phil Anderson suggested spending some time at Bell Labs (which I did two years later), and on the following weekend I went for my first hike to Buckskin Pass with Hide Fukuyama and other colleagues. The weather was perfect – what a summer! Since then I have returned to the ACP many times and always had most valuable discussions, several of which led to publications. For those reasons the ACP (and especially the inspiring atmosphere of Hilbert Hall) had a profoundly positive influence on my scientific development and career. I have always been most grateful for that.

Weiler, Tom

In the summer of 1981 at Aspen I found that the cosmology group seemed to be displaying a lot of camaraderie and was having much fun with their research. The group included Dave Schramm, Gary Steigman, Mike Turner, Rocky Kolb, Keith Olive... I believe this was the first time I had met these fine people. I decided to move my research more into their direction. I began by reading S. Weinberg's book, Gravitation and Cosmology, pretty much cover to cover. Being a postdoc in those days allowed me to spend the months to do so, and it all began with some weeks at Aspen. For motivation, I set myself a related research project, the aborption of CR neutrinos by the relic big–bang background. The resulting mfp was interesting if a not–too–heavy Z boson existed. The much anticipated Z boson was discovered at CERN in 1983. My paper, begun at Aspen because of the friendliness of the place and the people, turns out to be the second–most cited of all my papers. The merging of particle physics and cosmology in this work gave me a leg up in the emerging field. Turner and Kolb cleverly named the field “inner–space, outer–space,” and because of Aspen, I was along for the ride.

I have continued involvement with this “Aspen/cosmology” group to this day, in various ways. For example, in 1988 Dave Schramm enticed me to join him on a “strenuous” climb up a mountain in the Tyrol region of Italy. We took a two–day stopover as we traveled from a meeting in Trieste to a meeting in Munich. Dave led and I was tethered to him. He told that the point was, if I fell he and the tether would arrest the fall. I asked him what happens if he fell. He answered that wasn't going to happen. I pictured several hundred pounds of manhood having a few seconds to kiss their backsides goodbye. So it was quite reassuring to hear that this wasn't going to happen. At the top of the mountain, we stayed overnight in a climbers' lodge. In the morning, icing had made our chosen path down inaccessible, and we had to descend an “alternate” route which literally put us in a different country. Wild gesticulating on our part convinced a German–speaking farmer to call a taxi and arrange a 65–mile journey up the valley to, and over the next pass, and then back to our car. Many have climbed once with Dave; few have climbed twice with Dave. I am among the one–timers. And I do cherish the adventure, and the special time spent with Dave.

Whiteson, Daniel

Last summer at the ACP particle physics workshop, I asked every theorist the same question: “What have we forgottento look for at the LHC.” One young theorist, Kathryn Zurek from Michigan, had a perfect example. We began collaborating and it has become a large part of my current research plan. Just what I was looking for!

Williams, Bob

The Aspen Center for Physics is a phenomenon. Half a century ago who would have predicted its huge influence on modern physics? The fact is, after having been a participant in approximately 17 consecutive summer astrophysics programs, I admit to having had the 'Center Experience' imprint its wide range of thinking on my own professional efforts. The inspiration I received from being enlightened by and/or defending my ideas with some of the original thinkers in physical sciences has definitely shaped my professional ethos. Enjoying the music from the nearby tent has been a part of this experience. Many times I've wished we could bring back the great composers and enlighten them with what we've learned about the universe in the same way that their music has enriched us.

Woelfle, Peter

Visits at the Aspen Center for Physics have influenced the direction of my research positively in many ways. In particular I remember my visit in 1985, when I first learned about auxiliary particle representations of correlated electron problems. That visit triggered an extensive activity in my group on the search for improved methods and applications of slave particle theories, lasting to this day. That very summer I went hiking with a group of colleagues, including Phil Anderson. As we passed one of the Cairns along the path I put a stone on top, remarking that this is what hikers do in the Alps to help maintain the structure. When we passed the next Cairn, Phil put a stone on top as well - apparently the idea sounded convincing!

I am very grateful for the opportunity I had to visit ACP so many times. It every time has been inspiring for my research. Not to forget, the many friends I have made at Aspen have enriched my life.

Yaffe, Laurence

My sojourns at ACP have always been full of stimulating exchanges of information, but the impact on my own research has usually been of a 'gestational' nature – so it is hard to point to specific results which are directly tied to a stay at ACP. My best story involving ACP and impacts on research concerns anomaly cancellation in superstring theory and the first string theory 'revolution.' During the summer of 1984, Michael Green gave an outdoor seminar announcing his discovery, together with John Schwarz, of the cancellation of anomalies in type I string theory. I believe I was the only one from Princeton in the audience at the time, and I was returning to Princeton in the next day or so. Upon my return, I was asked over lunch “What's the news from Aspen?” and I related what I had just heard. At the time it seemed to me to be technically clever but rather far removed from any of the 'real' physics I was thinking about. But Ed Witten grasped its significance immediately, and instantly started focusing on string theory. The rest is history... That's my cameo role in the development of string theory. For confirmation on this, click here for Michael Green's 2007 talk on “The Birth of String Theory.” Without the ACP, who knows how much slower progress would have been.

Ziherl, Primoz

During the past six years, I have regularly participated in workshops and conferences at the Aspen Center for Physics. The reason for this is twofold: The events organized were cutting–edge, and their format is a perfect retreat from the duties at the university. All of my stays at ACP were very productive both in terms of research; several papers of mine were conceived, worked on, or finalized while I was at ACP. The events seem to attract a diverse yet balanced mix of physicists and I have benefited very much from the exchange with fellow participants, especially when I shared an office with a person from a completely different background. The stays also helped me advance my teaching skills and philosophy. I work in soft condensed matter and in biophysics, and these fields are at a critical stage where introducing them at an undergraduate level seems a good idea if not necessary. In Aspen I had plenty of opportunities to discuss these issues with colleagues. I do not really know what it is that makes ACP so special. Nature helps and the staff makes us feel very welcome. Do maintain the atmosphere and the style of doing physics at ACP.