Physics Research

Physics faculty and research groups are active in many different areas, including:

Experimental Elementary Particle Physics

Activities in elementary particle physics are aimed primarily at finding physics beyond the Standard Model. Experimental efforts employ hadronic colliders, e+e- colliders, neutrino beams, and muon beams at several international facilities. Current experiments include the Large Hadron Collider at CERN, which is searching for the Higgs boson and physics beyond the Standard Model; the MINOS and Nova experiments at Fermilab, studying long baseline neutrino interactions; the BABAR experiment at SLAC, searching for new physics in CP-violating and other rare processes in B meson and tau lepton decays, and the mu2e experiment at Fermilab, searching for charged lepton flavor violation.

Affiliated Faculty: Sunil Golwala, David Hitlin, Harvey Newman, Ryan Patterson, Frank Porter, Maria Spiropulu, Nick Hutzler

Theoretical Elementary Particle Physics

The particle theory group studies the unification of interactions based on string theory, the detailed properties of hadrons described by QCD, the quantum properties of black holes, the foundations of cosmology, including dark matter and dark energy, and other aspects of mathematical physics.

Affiliated Faculty: Clifford Cheung, Sergei Gukov, Anton Kapustin, Hirosi Ooguri, David Politzer, John Preskill, John Schwarz, Mark Wise

Nuclear Physics

The interests of the nuclear group include understanding the detailed properties of neutrinos and performing precision nuclear measurements to search for physics beyond the Standard Model. Neutrino oscillations are investigated at off-campus facilities using accelerators and antineutrinos produced in reactors to provide detailed information on the relative neutrino masses and mixing properties. Precision measurements of neutron decay allow sensitive searches for new physics, while measurements of the neutron electric dipole moment may help explain the dominance of matter over antimatter in the universe.

Affiliated Faculty: Brad Filippone, Nick Hutzler

Observational Astrophysics

Research in this area covers a broad range of topics using observational tools covering the entire electromagnetic spectrum.

The high-energy astrophysics group at the Space Radiation Laboratory (SRL) uses X-ray and gamma-ray detectors aboard spacecraft and balloons to investigate energetic processes from compact astrophysical objects, including gamma-ray bursts from neutron-star and black-hole systems, supernova and hypernova dynamics, and the development of stars and galaxies in the early universe.

The cosmic ray group at SRL uses data from a variety of spacecraft to study the composition of energetic particles arriving from the sun, the local interstellar medium, and beyond, in order to understand the origin and acceleration of energetic particles in space.

The ultraviolet astronomy group uses satellite observations, such as from the GALEX spacecraft, to explore the ultraviolet sky. Studies include the birth and death of stars, galaxy dynamics and evolution, and other areas.
The submillimeter astronomy group studies star formation, interstellar gas, galaxies, and quasars using the Caltech Submillimeter Observatory and other facilities. An active program is also under way to develop new superconducting detector technologies for use at these wavelengths, in collaboration with scientists at the Jet Propulsion Laboratory.

The infrared astronomy group studies a host of astrophysical phenomena using Caltech's Palomar Observatory, the twin10-meter optical telescopes at the Keck Observatory, and observations from the Spitzer Space Telescope. Caltech also manages the Spitzer Science Center on campus.

Affiliated Faculty: James Bock, Sunil Golwala, Fiona Harrison, Chris Martin, Tom Phillips, Tom Prince, Tom Soifer, Edward Stone, Jonas Zmuidzinas

Theoretical Astrophysics

The TAPIR (Theoretical Astrophysics Including Relativity) group carries out research on an ever-changing list of topics, including high-energy astrophysics and the physics of black holes and neutron stars, gravitational-wave astrophysics, cosmology, the formation of stars and galaxies in the early universe, and general relativity.

Affiliated Faculty: Yanbei Chen, Peter Goldreich (GPS), Philip Hopkins, Christian Ott, Sterl Phinney, Kip Thorne


The observational cosmology group explores the structure and dynamics of the early universe using precise measurements of the cosmological microwave background radiation from detectors on the ground, on balloons, and on spacecraft. Efforts to directly detect dark matter are also underway. These experiments include an active program of detector development in collaboration with scientists at the Jet Propulsion Laboratory. Theoretical studies seek to understand the large-scale structure of the universe, including the physical nature of dark matter and dark energy.

Affiliated Faculty: James Bock, Sunil Golwala, John Preskill, Mark Wise

Gravitational-wave Astronomy

Observations from the LIGO and LISA projects seek to use gravitational radiation to study a variety of astrophysical sources. Theoretical studies are aimed at developing sensitive data analysis techniques and calculating G-wave signals from sources such as coalescing black holes and neutron stars.

Affiliated Faculty: Sterl Phinney, Tom Prince, Kip Thorne

Gravitational Wave Science with LIGO

Caltech is host to the Laser Interferometer Gravitational-wave Observatory (LIGO) Laboratory, which is constructing advanced detectors that will begin data-taking in 2015; we expect to make the first detections of GWs in subsequent years. We work closely with the Caltech Theoretical Astrophysics group and several Caltech precision measurement groups, and with the LIGO Scientific Collaboration.

Affiliated Faculty: Rana Adhikari, Alan Weinstein

Condensed-Matter Physics

Areas of interest include correlated electron systems, 2-D matter, phase transitions, atomic and excitonic Bose condensation, nanomechanical and nanoelectronic systems, biosensors, quantum electromechanics, phonon physics, high-temperature superconductivity, graphene and carbon nanotube systems, quantum entanglement, dynamics of disordered systems, chaos, pattern formation, and systems far from equilibrium. Resources include numerous labs in the Caltech physics department, at the Kavli Nanoscience Institute at Caltech, and at the Jet Propulsion Laboratory. For more information, please visit the CMP Website.

Affiliated Faculty: Jason Alicea, Michael Cross, Jim Eisenstein, Manuel Endres, David Goodstein, David Hsieh, Alexei Kitaev (IQI), Ken Libbrecht, Olexei I. Motrunich, John Preskill (IQI), Gil Refael, Michael Roukes, Axel Scherer, Nai-Chang Yeh, Ahmed Zewail

Quantum Optics and Information

Research on campus and at the Institute for Quantum Information at Caltech includes studies of the nature of quantum computation and quantum information, cavity quantum electrodynamics, algorithms and error correction techniques in quantum computation, and generally how quantum physics can be harnessed to improve the acquisition, transmission,and processing of information.

Affiliated Faculty: Fernando Brandao, Manuel Endres, Jeff Kimble, Alexei Kitaev, John Preskill, Nick Hutzler

Institute for Quantum Information and Matter

The Institute for Quantum Information and Matter (IQIM) investigators span Caltech's departments of physics, applied physics, and computer science, and are interested in a wide spectrum of both experimental and theoretical research topics.  These topics include, but are not limited to, quantum information science, quantum many-body physics in condensed matter and atomic gas systems, topological states of matter, quantum optics and light-matter interactions at the quantum level, quantum cavity-optomechanics, and quantum metrology. For more information, please visit the IQIM Website.

Affiliated Faculty: Rana Adhikari, Jason Alicea, Xie Chen, Yanbei Chen, Jim Eisenstein, Manuel Endres, David Hsieh, Jeff Kimble, Alexei Kitaev, Olexei I. Motrunich, John Preskill, Gil Refael, Nai-Chang Yeh

Physical Biology

One of the most exciting frontier areas in modern physics is the study of living matter. Because of spectacular advances in technologies such as microscopy and DNA sequencing, it is now possible to have the kind of dialogue between theory and experiment in the study of living organisms that is the life blood of traditional physics. Research in physical biology at Caltech focuses on a broad array of topics ranging from the development of new technologies for single-cell mass spectrometry to the use of statistical mechanics to describing signaling and regulatory networks to quantitative approaches in neuroscience.

Affiliated Faculty: Michael Dickinson, Michael Elowitz, Lea Goentoro, Markus Meister, Lior Pachter, Rob Phillips, Michael Roukes, Matt Thomson