Rosenbaum to Retire as Caltech President at the End of the 2025–26 Academic Year

Thomas F. Rosenbaum, the ninth president of Caltech, will retire on June 30, 2026, after 12 years in the position. He will remain at the Institute as a member of the faculty.

Rosenbaum announced his intention to step down from his administrative leadership role at the end of the next academic year in a letter to the Caltech community. Rosenbaum wrote that, as president, his job "has been to sustain and enhance our culture, our values, our intimate environment, our commitment to primary sources and first principles, our defense of evidence-based inquiry, our devotion to learning and discovery."

He added: "Caltech boasts a solid financial footing, remarkable new research and educational facilities, and, most importantly, the capacity to recruit and sustain the brightest and most innovative individuals from every walk of life and from every corner of the world. Our secret for success is no more complicated than the people who comprise our community, but it requires diligence, awareness, and commitment to be able to soar ever higher."

Rosenbaum assumed office on July 1, 2014, and served two full terms as Caltech's president. At the request of the Caltech Board of Trustees, in 2023 he agreed to serve part of a third term, planning to end his tenure at the end of the 2025–26 academic year. In publicly announcing this plan, Rosenbaum positions the Board and the Institute's faculty to begin the Institute's next presidential search, details of which will be announced next week.

"I have every confidence that the faculty and Board of Trustees, working in concert, will identify and attract a dynamic new president to lead the Institute to an even brighter future," Rosenbaum said, while also making clear his continued commitment to his service as Caltech's president and his responsibility to steward the Institute, its resources, and its research and academic enterprise throughout the year ahead. "There remains important work to be done and new heights to scale over the next 15 months."

Throughout his tenure at Caltech, Rosenbaum has sought to position the Institute and its people to fulfill their potential. In his inaugural address on October 24, 2014, Rosenbaum described his intent to "ensure that Caltech's fundamental identity comes from within and that it is never imposed from without" and that the Caltech community continues to "distill the hard-won experience of the past so that we may create a sense of magic and wholeness for the future."

In the same address, he outlined five fundamental elements that characterize Caltech and that, taken together, he said, "yield intellectual magic":

• An absolute commitment to excellence. "Every appointment—student, faculty and staff—matters. Intrinsic to this strategy is the need for diversity: diversity of thought, diversity of background, diversity of experience."
• Ambition, at every scale. "We are at a time in the history of science and technology where competition for federal funds drives the system to conservatism, but the genius of Caltech is its fearlessness to try new ideas, its willingness to absorb risk and even fail if the potential is transforming discovery."
• Focus. "As the constraints become more pronounced, we will be challenged even more profoundly to define areas where the Institute can be a world leader and where it cannot. We will have to forge partnerships … while protecting our capacity to set the intellectual agenda."
• Intimacy and intensity. "This is a visceral feature of Caltech, built on an organizational structure with few disciplinary barriers and the cultural expectation of shared knowledge."
• Perspective. "The arts help us to function as life thrusts us into situations where we have to conceive problems outside of the structures that define them. It provides us with an elasticity of thought and familiarity of experience not fully our own, while challenging us to define the essence of what we believe."

Over the 11 years that followed this address, those pillars have guided and continue to guide Rosenbaum's presidency. He is an advocate for the value of fundamental science and curiosity-driven research and continues to steer the Institute and its community to new discoveries and innovation in the service of humanity, in areas ranging from neuroscience and translational medicine to sustainability and green chemistry; astronomy and planetary science; the no-longer futuristic fields of robotics, quantum computing, and artificial intelligence (AI); and more.

Under Rosenbaum's leadership, Caltech more than doubled its endowment and completed a historic capital campaign, Break Through, that raised $3.4 billion from more than 14,500 donors; instituted programs to enhance students' educational and co-curricular experiences and make a Caltech education more affordable; and strengthened the Jet Propulsion Laboratory (JPL), which the Institute manages for NASA. Caltech also has forged strategic partnerships with other research-focused institutions and private industry that will propel science and engineering advances far into the future; envisioned and constructed new campus facilities and spaces that enable researchers to pursue bold ideas and profound questions; and initiated programs and projects that connect the broader community and region to Caltech, to share in the excitement of discovery.

Those discoveries have included the 2015 observation of gravitational waves, ripples in spacetime created by the most cataclysmic events in the universe; the demonstration of the first wireless transmit of power in space, which also led to detectable power being beamed to Earth for the first time; the development of a new type of vaccine that protects against the COVID-19 virus and closely related viruses; and the launch of landmark missions by JPL to study the early history of the universe (SPHEREx) and our closest planetary neighbor (Mars 2020: Perseverance Rover). During Rosenbaum's tenure, members of Caltech's world-renowned faculty were awarded three Nobel Prizes (including two for the detection of gravitational waves); faculty members have also been recipients of the National Medal of Science, the Breakthrough Prize, the Kavli Prizes, MacArthur Fellowships, and other significant honors.

"Since his appointment in 2014, Tom has personified Caltech's mission to benefit society through research integrated with education. He expanded our intellectual enterprise, strengthened our connection to the broader community, and served as a constant steward of Caltech's legacy at the forefront of discovery, innovation, and education," said David W. Thompson (MS '78), chair of the Caltech Board of Trustees, in a statement today to the Caltech community.

Thompson also praised Rosenbaum for his steady leadership and for providing clarity in direction through historic challenges of a global, regional, and local scale. Rosenbaum's leadership through such events—from the COVID-19 pandemic; to a reconsideration of Caltech's admissions practices and the co-curricular student experience, and reflection on the Institute's past; to the devastating Los Angeles fires that swept through the Altadena and Pacific Palisades communities, displacing thousands and destroying the homes of more than 300 Caltech community members—demonstrates the strength and resolve of Caltech and its people. By working together, supporting one another, and taking reasoned and informed action, often with the counsel of the campus's own scientific experts, the Institute has continued to flourish.

"On a personal level," Thompson added, "I have admired Tom's ability to function as a top-ranked scientist, an informed historian of higher education, and a constant voice emphasizing the importance of science and technology as a primary means of improving the human experience."

An expert on the quantum mechanical nature of materials, work that he continued during his Caltech presidency and will pursue after ending his presidency, Rosenbaum has been a member of the country's academic community and an advocate for fundamental science and engineering research for more than 40 years. He came to Caltech in 2014 from the University of Chicago, where he served as the university's provost from 2007 to 2014 and was the John T. Wilson Distinguished Service Professor of Physics. He held a variety of academic and administrative leadership roles throughout his tenure there, which included directing the University of Chicago's Materials Research Laboratory from 1991 to 1994 and its interdisciplinary James Franck Institute from 1995 to 2001 before serving as vice president for research and for Argonne National Laboratory from 2002 to 2006. Prior to joining University of Chicago's faculty in 1983, Rosenbaum conducted research at Bell Laboratories and at IBM Watson Research Center.

Rosenbaum received his bachelor's degree in physics with honors from Harvard University in 1977 and PhD in physics from Princeton University in 1982.

He serves on the Society for Science Board of Trustees, for which he was named chair in 2024; as General Member of the Aspen Center for Physics; and on the American Academy of Arts & Sciences Los Angeles Committee.

"Working with Tom both as a physicist and as the chair of the Faculty Board is always a delight and an inspiration," says Gil Refael, Taylor W. Lawrence Professor of Theoretical Physics, who has served as the chair of Caltech's faculty board since 2022. "Tom leads Caltech with both a mind and a heart dedicated to the advancement of science, and the people who do science. Caltech is a special place. It is a haven where elite researchers can forge ahead on our joint mission, with minimal disruption and with strong collegiality. Tom fit right in, and worked tirelessly over the last decade to protect and strengthen our Institute. It is a distinct privilege for me to work alongside Tom, and I'm looking forward to another year of our collaboration."

In celebration of what Rosenbaum has achieved thus far, the following highlights some of the defining contributions, events, and developments of his tenure.

Advancing Research

Research is at the heart of Caltech, in all aspects and areas of contribution. The Institute's scholars, scientists, engineers, and inventors investigate and address profound scientific questions and pressing societal challenges in an environment that encourages and supports high-risk, high-reward endeavors in areas of study such as quantum science, AI, bioinformatics, economics, energy, and sustainability, while seeking to answer fundamental questions about the nature of life itself and human behavior.

Throughout his tenure, Rosenbaum ensured that Caltech researchers had the resources and freedom to create, experiment, and define new areas of inquiry, leading to innumerable accomplishments, including:

• The first direct observation of gravitational waves, generated from the merger of two black holes, by the twin National Science Foundation-funded LIGO detectors. The discovery confirmed a major prediction of Albert Einstein's general theory of relativity. Subsequent upgrades to the LIGO observatories, which were conceived, built, and are operated by Caltech and MIT, as well as the addition of other gravitational-wave observatories to the LIGO collaboration, have increased the sensitivity of the instruments, leading to more detections of black-hole collisions, and mergers between pairs of neutron stars and of a black hole and a neutron star.
• The first demonstration, by Caltech's Space Solar Power Project (SSPP), of the ability to harvest solar power in space and wirelessly transmit it to Earth's surface. SSPP was formed thanks to donations, which will eventually exceed $100 million, from Donald Bren, a life member of the Caltech community, and his wife, Brigitte Bren, a Caltech trustee.
• The creation of the mosaic-8 nanoparticle, a new type of vaccine that provides protection against a spectrum of COVID-19-causing viral variants and closely related viruses.
• A new method that enables standard computers to measure quantum computing error rates—a crucial step for the realization of the promise of quantum computing—as well as an ultraprecise timekeeper produced from the merger of atomic clocks and quantum computers that will help physicists better probe the laws of nature, and a new method for converting electrical quantum states into sound and back again.
• Sophisticated new robotic devices, many drawing inspiration from nature, such as a flying robot bat, a freely moving artificial jellyfish and a bionic jellyfish to explore Earth's oceans, and a bioinspired robot capable of eight different types of motion.
• New methods to break the human-made bonds between carbon and silicon found in widely used chemicals—a first step toward rendering these chemicals biodegradable—and to "evolve" bacteria that can create these bonds as well as bonds between carbon and boron atoms. Such work allows chemists to make these compounds in "greener" ways. Other sustainability-focused efforts led to new techniques to mitigate environmental damage from chemical production, technologies for capturing carbon dioxide from ocean water, and methods to optimize wind-farm design.
• Novel advances leveraging AI and machine learning, including to develop a catheter tube that reduces the risk of bacterial infections. Other AI- and machine-learning-informed methods have been developed to determine which types of lung cancer are most likely to metastasize, to identify millions of previously unidentified earthquakes, to predict South Asian monsoon rainfall levels, and to construct unmanned aerial vehicles that respond in real time to changing wind conditions. Such research has been propelled by Caltech's AI4Science initiative, which aims to integrate modern AI tools into every area of science and engineering. At the same time, recognizing that new technologies such as AI can also bring unexpected risk, Caltech experts also were at the forefront of efforts to measure the public health impact of pollution generated by AI data centers.

Over the past 11 years, Caltech also continued to build on its decades-long legacy of groundbreaking neuroscience research and the study of the brain and behavior. In October 2014, Caltech experts led or co-led a remarkable six of the 58 projects supported by the inaugural round of funding from President Barack Obama's Brain Research through Advancing Innovative Neurotechnology (BRAIN) Initiative. The following year, Caltech neuroscientists showed that an implanted neural prosthetic device (a brain–machine interface, or BMI) could convert a paralyzed patient's intention to move a robotic limb into the physical movement of that device. Further progress in this work—which inspired a landmark $115-million donation to Caltech for neuroscience research—has led to the development of a BMI that may one day allow patients who cannot speak to think of a word and have it accurately transmitted to a computer and the creation of a new type of window into the brain that allows researchers to directly see brain activity using ultrasound, among many other advances.

In addition, the Institute strengthened its research efforts in medical engineering through the endowment of the Andrew and Peggy Cherng Department of Medical Engineering, and in translational medicine, with the establishment of the Merkin Institute for Translational Research. It also formalized a relationship with City of Hope, enabling collaborations that further both basic scientific research and translational projects. In partnership with the Heritage Medical Research Institute (HMRI), founded by Caltech trustee Richard Merkin, Caltech created the Heritage Research Institute for the Advancement of Medicine and Science at Caltech, which provides support for faculty conducting translational medicine research.

With such support, Caltech researchers continued their quest to improve modern medicine and the human condition, developing an array of wearable biosensors that track important health measures such as metabolites, hormones, proteins, and medication levels in human sweat. They also devised remoted-controlled bacteria for targeted drug delivery to tumors inside the body; noninvasive methods to continually monitor blood pressure and assess stroke risk; contact lenses for preventing blindness in diabetics and prosthetic heart valves inspired by dragonfly larvae; gene therapy for repairing nerves in the brain; and a host of new technologies for improved medical imaging.

Beyond fundamental exploration, Caltech's scholars design and build new instrumentation that they and other researchers use to advance discovery and knowledge. Such instruments include the Next Generation Palomar Spectrograph at Caltech's Palomar Observatory, which is used to study in detail objects ranging from asteroids and comets to distant stars, galaxies, and supernovae; and a suite of Caltech-designed instruments to augment the capabilities of the W. M. Keck Observatory atop Maunakea in Hawai'i, including: the Keck Cosmic Web Imager, one of the world's best instruments for taking spectral images of celestial objects; the Keck Cosmic Reionization Mapper, designed to provide detailed maps of gas that surrounds dying stars and of other elements of the cosmic web; and the planet-imaging Keck vortex coronagraph.

Additionally, Caltech researchers invented a new type of all-electron instrument for measuring processes that happen at femtosecond (one millionth of one billionth of one second) timescales; and designed a first-of-its-kind mass spectrometer to rapidly identify hundreds of isotopic forms of single molecules, offering insight into a molecule's history and formation environment—information crucial for current geochemistry analyses and future Mars sample-return efforts.

Most recently, JPL experts developed the Compact Fire Infrared Radiance Spectral Tracker, which produces detailed images of high-temperature surfaces such as land scorched by wildfires.

Furthermore, researchers from campus and JPL secured new funding for ambitious projects to build and test scientific instrumentation to study Earth and the universe—on faster timescales and at lower cost than previously possible—through the 2024 creation of the Brinson Exploration Hub, made possible through a $100 million donation from The Brinson Foundation to Caltech.

Improving the Student Experience and Support for Early Career Researchers

Caltech is consistently recognized as being among the world's top research and education institutions. As with his predecessors, Rosenbaum, aligned with the Institute's long legacy of not settling for the status quo, instituted new programs, appointed advisory committees, and reorganized administrative offices to enhance the Institute's ability to attract the best and brightest student applicants, to ensure that admitted students had access to the financial resources and support needed to afford a world-class education, and to improve their experiences at Caltech.

Under Rosenbaum's leadership, the Institute increased investment in undergraduate admissions to ensure that Caltech can effectively communicate the benefits and value of a Caltech education to potential applicants and increased the representation of Pell Grant students at the undergraduate level as well as the recruitment of women and rural students.

In fact, the Institute has further expanded its investment in undergraduate financial aid for lower- and middle-income students. Caltech now offers grant aid packages (meaning no loans, no repayment) that fully cover the cost of tuition, fees, housing, and food, to most students with family income of less than $100,000. Students with family income of less than $200,000 can expect to be offered grant aid packages that fully cover the cost of tuition.

At the same time, the president oversaw the launch and development of new programs for students, postdoctoral scholars, and early-career faculty to promote their academic development and training, increase exposure to and collaboration across fields, and support the transition to campus and their academic careers, at all stages of the process. The First-year Success Research Institute (FSRI) and the Graduate Summer Research Institute (GSRI) have proven to be instrumental in introducing incoming undergraduate students and graduate students to the rigor of Caltech and have helped participants to find community and colleagues across fields. Similarly, the Presidential Postdoctoral Fellowship program helps recruit and retain promising postdoctoral scholars, providing access to professional training and development opportunities that serve participants throughout their career.

Strengthening the Jet Propulsion Laboratory

JPL, founded by Caltech researchers in the 1930s, has been managed by Caltech for NASA since the nation's civilian space agency was established in 1958. Caltech's contract for the management of JPL has been renewed twice, for five-year terms, under Rosenbaum's tenure.

Since the president took office on July 1, 2014, JPL has launched 40 missions, including orbiters, landers, rovers, CubeSats, technology demonstrators, and more; 43 missions are currently active.

Institute faculty are presently leading five NASA missions as principal investigators or principal scientists, including the just-launched SPHEREx, an orbiting observatory that will map the entire sky in three dimensions, helping to answer fundamental questions about the first moments after the birth of our cosmos; the Mars Perseverance rover, which is traversing the surface of the Red Planet, searching for signs of ancient life; and NuSTAR, an orbiting X-ray telescope designed to probe the hottest, densest, and most energetic objects in space. Other Caltech faculty lend their expertise to approximately two dozen more active NASA missions.

Caltech has fostered innovative collaborations among campus-based faculty and JPL-based colleagues, with the Institute providing access to leading research facilities and instrumentation. Most recently, in 2024, the Institute announced the creation of the Brinson Exploration Hub, which provides internal support and funding to interdisciplinary teams of scientists and engineers to develop and test novel scientific concepts and instrumentation on faster timescales and at lower costs than is possible through conventional means.

Meanwhile, Caltech's Center for Autonomous Systems and Technologies (CAST) is developing self-driving, and sometimes self-assembling, autonomous robots, instruments, and vehicles. CAST is also home to a wind tunnel capable of simulating the conditions and environment on Mars, and the center tested the Ingenuity Mars Helicopter before its launch and demonstration on Mars.

Game-changing Fundraising: Break Through and the Initiative for Students

The Break Through campaign, launched in 2016 and ended on September 30, 2021, raised $3.4 billion—a record for an institute of Caltech's size—providing a transformational level of philanthropy for the Institute and its people.

Gifts to Break Through include a $750 million pledge by senior trustee Stewart Resnick and his wife, Lynda Resnick, to propel Caltech's sustainability initiative, augmenting the Resnick Sustainability Institute; more than $139 million from the estate of Allen V. C. Davis to provide endowed support for faculty; $137 million in unrestricted support from the late Gordon Moore (PhD '54) and Betty Moore; $115 million from Tianqiao and Chrissy Chen to create the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech; and $100 million from Donald Bren, a life member of the Caltech community, and his wife, Caltech trustee Brigitte Bren, to launch the Space-Based Solar Power Project and support endowed professorships.

In addition, nearly $30 million was donated by Caltech's faculty and staff, and $770 million was donated by alumni. More than 6,000 gifts were received from first-time donors to Caltech.

Following Break Through and in striving to further amplify support for undergraduate and graduate students, Rosenbaum spearheaded the Initiative for Students. The Initiative seeks to raise $250 million, which includes goals of $100 million for undergraduate scholarships, $60 million for graduate fellowships, $30 million for health and wellness programs, $25 million for career advising, and $35 million for co-curricular experiences.

Fostering Partnerships

Although Caltech remains small, focused, and true to its specializations and expertise, the Institute has worked to expand its already outsized global impact through strategic and intentional partnerships. Under Rosenbaum's leadership, the Institute formalized in 2021 a partnership with Carnegie Science to advance life and environmental science research in Pasadena; and in 2022 became the new home for the independent, nonprofit American Institute of Mathematics (AIM), funded by the National Science Foundation (NSF), which organizes and funds focused collaborations among pure and applied mathematicians, theoretical biologists, computer scientists, physicists, and other scientists working on long-standing math problems.

Continuing a long tradition of collaboration and partnership with industry in the advancement of fundamental science and the commercialization of Caltech research and technologies, Caltech in 2018 welcomed to campus its first corporate partner, Amazon Web Services (AWS), the cloud-computing branch of Amazon. Together, Caltech and AWS foster the development of quantum computers and related technologies that have the potential to revolutionize data security, machine learning, medicine development, sustainability practices, and more.

More recently, Caltech announced a multiyear partnership with Broadcom to advance quantum science research and discoveries with the potential to seed new innovative technologies and applications. The Broadcom partnership will establish the Broadcom Quantum Laboratory at Caltech, a physical collaboration space that will bring together experts in the fields of quantum computing, quantum sensing, quantum measurement, and quantum engineering.

To leverage these relationships, continue to support and protect the Institute's vigorous pipeline of invention and innovation, and further nurture an entrepreneurial environment, Caltech recently dedicated funds to support researchers in the development of their research and technologies, the creation of an innovation center and dedicated research and start-up spaces on and in the vicinity of campus, and the launch of an entrepreneurial programs and services to support faculty and students.

Campus Development

Throughout Rosenbaum's tenure, Caltech's campus—regarded as one of the most beautiful college campuses in California—has been further developed to provide sustainable, state-of-the art facilities and spaces that encourage collaboration, enable discovery and innovation, and enhance the training environment for tomorrow's future STEM leaders.

Caltech's new and newly renovated buildings include:

• Bechtel Residence, the Institute's newest undergraduate residence, which allows Caltech to house all undergraduates on campus for all four years;
• Tianqiao and Chrissy Chen Neuroscience Research Building, a 150,000-square-foot, state-of-the-art facility that brings together, in one shared space, researchers exploring the intricacies and workings of the brain.
• Dr. Allen and Charlotte Ginsburg Center for Quantum Precision Measurement, the campus's newest building, now in development with an expected completion date in 2026. The Ginsburg Center will unite researchers in precision measurement, quantum information, and the detection of gravitational waves.
• Hameetman Center, the campus's new central gathering place for community activity, opened in February 2019. Named in honor of Caltech trustee Fred Hameetman (BS '62) and his wife, Joyce, the center features a large public lounge, an expanded Red Door Marketplace, the Caltech Store, music rehearsal facilities, student-club rooms, a multipurpose room, and a conference room.
• Ronald and Maxine Linde Hall of Mathematics and Physics renovation, which reimagined what was a 1923 experimental facility for electric power transmission to create the home of Caltech's department of mathematics. Renovated through a gift from Caltech alumnus Ronald Linde (PhD '64), vice chair, emeritus, of the Board of Trustees, and his wife, Maxine, Linde Hall is now the home to more than 125 mathematicians.
• Resnick Sustainability Center (RSC), made possible by a $750 million pledge from Lynda and Stewart Resnick, serves as the physical hub for the Institute's sustainability initiatives. The new building provides specialized equipment, space, dedicated staff members, and resources accessible to researchers from across Caltech's Pasadena campus and JPL. It is home to the four resource centers of the Resnick Sustainability Institute (the Solar Science and Catalysis Center, Remote Sensing Center, Ecology and Biosphere Engineering Facility, and Translational Science and Engineering Facility), as well as Caltech's undergraduate chemistry laboratories, additional classroom and lab spaces, a high bay, and a solar roof.

Community Engagement

Fostering connections between Caltech and the broader community has been among Rosenbaum's top priorities, as such interactions allow the public to share in the excitement of innovation and discovery, and provide important perspective and understanding to the next generation of leaders in science and engineering. Throughout his tenure at Caltech, Rosenbaum has welcomed to campus eminent speakers, through the Presidential Distinguished Speaker Series, such as Katherine Fleming, CEO of the J. Paul Getty Trust; Bob Iger, CEO of the Walt Disney Company; Michael Lomax, president and CEO of the United Negro College Fund; and Leroy (Lee) Hood (BS '60, PhD '68), CEO of Phenome Health and co-founder and professor at the Institute of Systems Biology.

The Breakthrough Insights series featured Rosenbaum in conversation with luminaries such as SpaceX president and COO Gwynne Shotwell, Alphabet chairman John Hennessy, Zoom founder and CEO Eric S. Yuan, and Alibaba chairman and CEO Daniel Zhang. The president also welcomed Microsoft founder Bill Gates for a question-and-answer session with Caltech students.

Additionally, to expand Caltech's reach and to help the public understand scientific issues that capture attention but often are not fully understood, Caltech launched the Caltech Science Exchange, a faculty-vetted multimedia website that provides content explaining the science behind critical topics, including emerging viral threats, neuroscience, earthquakes, voting and elections, artificial intelligence, quantum science and technology, sustainability, and most recently the science of wildfires. Articles, faculty expert pieces, and live events convey the science behind societal experiences as they happen and add to a robust slate of programming that aims to introduce the public to Caltech's research and to the people who lead the discoveries.

In this vein and ultimately in support of Rosenbaum's vision for Caltech, the Institute recently revamped its century-old Watson Lecture Series, which offers accessible and engaging talks from scientists and engineers from Caltech's Pasadena campus and JPL who are at the forefront of discovery.

Caltech has also served since 2016 as the host for the Southern California Science Olympiad State Tournament, a team-based science and engineering competition for middle and high school students; in 2022, the Institute hosted the national tournament. Last fall, the Institute partnered with the Getty to present the PST ART exhibition Crossing Over: Art and Science at Caltech, 1920–2020, which showcased artists whose work engages with both the history of science and cutting-edge scientific research.