The Johns Hopkins Department of Physics and Astronomy research laboratories are well equipped with state-of-the-art tools. What’s more, the research of our faculty is truly global: some of us work at the Large Hadron Collider, the site of the world’s highest energy particle accelerator, at the Advanced Photon Source, the world’s brightest source of light, and with instruments on the Hubble Space Telescope, the world’s premier space observatory. Our faculty are also on the cutting edge of gravitational physics and gravitational-wave astronomy, preparing for the challenge of detecting gravitational waves in space with the Laser Interferometer Space Antenna (LISA). Closer to home, a special undergraduate laboratory sponsored by the Pew Charitable Trusts allows students to perform their own research under the guidance of faculty mentors. There is also a modern computer laboratory for the exclusive use of undergraduate physics majors.
Our department is strong and diverse, which gives students the opportunity to work with experts in a wide range of fields. Unlike some larger universities, most of our faculty members work with undergraduates. Studying and researching alongside people with this level of expertise and commitment to the field gives you a challenging environment in which to build your skills.
The department focuses on four primary areas of research:
The Center for Astrophysical Sciences (CAS) at Johns Hopkins is the home of more than 75 PhD-level astrophysicists. Using experimental, observational, numerical, and theoretical methods, the scientists in CAS lead research across the entire range of the discipline. Along with members of the nearby Space Telescope Science Institute, we form one of the largest astrophysics communities in the country.
Condensed Matter Physics
Condensed matter physics concerns itself with systems that have a macroscopically large number of elementary parts, typically electrons, atoms, or molecules. Collective behavior of many interacting particles cannot be reduced to the properties of individual particles: rigidity is a property of a solid, not of a single atom; superconductivity cannot be understood by examining one or two electrons. In the words of Nobel laureate P. W. Anderson, more is different.
The condensed matter physics groups at Johns Hopkins maintain active experimental and theoretical research programs covering many areas of their discipline. We investigate the properties of superconductors, topological insulators, liquid crystals, magnetic and superconducting nanostructures, surfaces and interfaces, fluids, granular materials, quantum magnets, and biological cells.
Cosmology and Gravity
The Cosmology and Gravity research group is engaged in a broad range of research that explores the nature of gravity and the origin and evolution of the Universe. Theoretical research is conducted on general relativity, alternative-gravity theories, gravitational-wave physics and astrophysics, physical and early-Universe cosmology, and dark matter and dark energy. Relevant experimental/observational work includes direct searches for dark matter, measurements of the cosmic expansion history, galaxy surveys, and cosmic-microwave-background measurements.
The particle physics group at Johns Hopkins conducts research in both theory and experiment. We have roughly 10 faculty members, 10 postdocs, and 20 graduate students involved in this enterprise. Our experimental group conducts research at the Large Hadron Collider at CERN as part of the CMS Collaboration. Our group is involved in the Higgs analysis and in searches for new physics, particularly those involving very heavy new particles. Our theory group studies problems in formal field theory and string theory, phenomenological issues, models for new physics beyond the Standard Model, and connections between particle physics and astrophysics and cosmology.
Physics and Machine Learning
Neural nets can perform complex tasks but what and how they learn is not understood. As Artificial Intelligence and Machine Learning make rapid strides, physicists at JHU in the physics and machine learning research group are working to understand these systems and incorporate them into Physics and Astronomy research. With their large numbers of neurons and connections, neural nets can be analyzed through the lens of statistical mechanics. We are working to characterize feature learning, optimization, and the scaling of ML systems using various datasets: images, text, the web, scientific measurements, etc.
Plasma, the fourth state of matter, is defined in the simplest terms as an overall neutral collection of charged particles dominated by electromagnetic forces. Whether astrophysical or produced in the laboratory, plasma exists over very large domains of densities and temperatures. Therefore, its properties are studied based on emission of radiation in ranges going from microwaves to very hard X and even gamma rays. Discrete (line) and continuous radiation is emitted by multiply charged ions interacting with electrons, and the physics of the emitting plasma is obtained through methods and techniques of plasma spectroscopy.
Our plasma spectroscopy program has grown out of the astrophysics research and extended to the domain of magnetically confined fusion plasma studies.