Bertrand Halperin stands as a preeminent theoretical physicist whose profound contributions have shaped modern understanding of condensed matter systems. He currently holds the distinguished position of Hollis Professor of Mathematicks and Natural Philosophy, Emeritus at Harvard University, following a storied career that began with his undergraduate studies at Harvard where he earned his A.B. in Physics in 1961. After completing his M.A. and Ph.D. in Physics at the University of California, Berkeley in 1963 and 1965 respectively, he spent a decade at Bell Laboratories where he established himself as a rising star in theoretical physics. His appointment to Harvard University in 1976 marked the beginning of a transformative period in his career, culminating in his promotion to the prestigious Hollis Chair in 1992 and his service as Chairman of the Physics Department from 1988 to 1991. Throughout his distinguished career, Halperin has maintained dual appointments as both a Senior Fellow in the Harvard Society of Fellows and Scientific Director of the Harvard Center for Imaging and Mesoscale Structures from 1999 to 2004.
Halperin's most groundbreaking contribution came in the 1970s when, together with David Nelson, he developed the theory of two-dimensional melting that predicted the existence of a hexatic phase between solid and liquid states, a prediction that was later confirmed experimentally and became known as the KTHNY theory. His pioneering work on quantum Hall systems in the 1980s fundamentally transformed understanding of electron behavior in two-dimensional systems under strong magnetic fields, where he demonstrated that quantized Hall systems necessarily featured conducting states at their boundaries. This insight proved crucial for understanding the exactness of quantized Hall conductance and laid essential groundwork for subsequent developments in topological phases of matter. His earlier research at Bell Laboratories on dynamic phenomena near classical critical points, conducted with Pierre Hohenberg and others, established foundational frameworks for classifying dynamic behavior at phase transitions using renormalization group methods. These theoretical advances have provided indispensable tools for physicists studying critical phenomena across numerous material systems and continue to influence contemporary research in statistical mechanics.
Recognized with numerous prestigious honors including the Wolf Prize in Physics in 2003 and the APS Medal for Exceptional Achievement in Research in 2019, Halperin's work has received sustained acclaim for its depth and transformative impact on condensed matter physics. His theoretical frameworks have not only advanced fundamental understanding but have also catalyzed experimental investigations that have revealed entirely new classes of quantum phases and phenomena. As an educator, Halperin has mentored generations of physicists, receiving the Phi Beta Kappa Teaching Award from Harvard in 2004 for his exceptional ability to convey complex theoretical concepts with clarity and insight. His more recent research continues to explore the profound implications of topology in quantum systems, extending his lifelong interest in the interplay between geometry and physical phenomena. The enduring legacy of Halperin's scholarship is evident in the widespread adoption of his theoretical constructs across multiple subfields of physics, cementing his position as one of the most influential condensed matter theorists of the modern era.
