Scientific Highlights

The Aspen Center for Physics (ACP) is a premier summer home for theoretical physicists worldwide. With a blend of workshops, informal discussion, and individual research, it has given birth to a wide variety of significant advances across all fields of theoretical physics, including cosmology, astrophysics, condensed matter physics, biophysics, and more. Below are scientific achievements which our physicists have cited as some of the ACP’s greatest breakthroughs.

1960s

1969-1970 – Pierre Ramond’s work led to the discovery of a new kind of symmetry called Supersymmetry, that can organize the universe’s building blocks by relating the properties of particles which transmit forces (bosons) and that behave like matter (fermions). Supersymmetric extensions of the Standard Model of Particle Physics form the basis of many attempts to unify all the forces of nature into a single framework.
1969-1970 – Robert R. Wilson and his team planned to construct the Fermi National Accelerator Laboratory (Fermilab), the US particle accelerator laboratory.
1969 – ACP physicists discovered links between the zero-viscosity superfluid state of a neutron-star’s core, and the phenomenon of pulsar glitches – the sudden increase in the rotation of a highly magnetized neutron star.

1970s

1974 – A summer program on strong interactions saw the initiation of seminal work by Thomas Appelquist and David Politzer on charmonium, a new type of state composed of heavy quarks, which was critical in the development of QCD and the standard model.
1978 & 1979 – Murray Gell-Mann, Pierre Ramond, and Richard Slansky developed the see-saw mechanism, a proposal explaining why the neutrino, a vastly abundant kind of subatomic particle, has such a tiny mass. (Independently, Peter Minkowski and Tsutomu Yanagida also developed the see-saw mechanism around this time.)
Mid-1970s – Work by a small group of pioneering theorists meeting regularly at the ACP set the foundations for the discovery of string theory in the next decade.

1980s

1984 –Michael Green & John Schwarz discovered “anomaly-cancellation” in string theory, which made the theory that the universe is made up of string-like rather particle-like components a viable quantum description of space and time. This finding triggered the modern string theory revolution.
1980s & 1990s – The ACP propelled the particle astrophysics and cosmological paradigm.

1990s

1991 – Paul Ginsparg founded the arXiv.org electronic scientific paper archive following discussions with Joanne Cohn. The arXiv revolutionized how physicists distributed their discoveries and is now the standard repository for work in this field. This model of open-access scientific publishing now ecompasses mathematics, computer science, economics, and much of biology. The invention of the arXiv massively broadened and democratized access to the latest scientific discoveries across the globe.
ACP participants helped to establish foundations of the AdS/CFT correspondence, a fundamental relationship between quantum theories of gravity and theories about interactions between elementary subatomic particles. The major advances in string theory and quantum gravity that it ensued sparked a “duality revolution” within these fields.
1990s & 2000s – ACP physicists did the early planning of cosmological surveys and facilities like the DEEP, the Dark Energy Survey (DES), the Rubin Observatory, and the Roman Space Telescope.
1990s-now – ACP physicists developed and applied topological field theory, which describes systems in which all physical measurements depend on the “topology” of a space: the set of properties of a geometry that do not change if it is continuously deformed, without making a hole or creating a new edge.

2000s

The ACP hosted initial meetings for LIGO (the Laser Interferometer Gravitational-Wave Observatory). LIGO demonstrated the existence of gravitational waves: ripples in space-time caused by massive, extremely accelerated objects, including merging black holes. The LIGO observatory and its founders went on to receive awards including the Breakthrough Prize and the Nobel Prize in Physics.

2010s

2015 – LIGO, based in Louisiana and Washington state, and the Virgo detector in Italy, demonstrated the existence of gravitational waves. LIGO-Virgo collaborators received the Nobel Prize in Physics. ACP conferences and workshops, started by Sydney Meshkov and Gary Sanders, were among the first to discuss the LIGO-Virgo detection of rare collisions between black holes and neutron stars, sparking numerous highly cited papers on the formation of these systems.
Research at the ACP spearheaded a paradigm shift in particle physics, broadening the traditional search for new particles with large mass and short lifetime, to focus also on long-lived particles, heavy and light. Indeed, theoretical work at the ACP led to an explosion of new ideas for particle searches, and proposals for the FASER, CODEX-b, SeaQuest, and MATHUSLA particle experiments.
ACP physicists were extensively involved in developing ideas connecting quantum information theory, quantum computation and the foundations of quantum gravity.
ACP physicists were instrumental in understanding the Sachdev-Ye-Kitaev (SYK) model, a description of materials with components which interact very strongly, producing unusual phenomena, including the ability to act as if they exist in one more dimension than they really do.

2020s

Over the past decade, the Center has hosted workshops and conferences in emerging and cross-disciplinary fields, including biophysics; quantum computing; quantum entanglement; atomic, molecular and optical physics; and machine learning. These workshops and conferences have seeded novel collaborations and insights, leading to publications that have had a major impact in these areas.
Each year, over 500 articles and publications acknowledge the ACP for advancing the work of their authors.