Howard John Carmichael (born 17 January 1950) is a British-born New Zealand theoretical physicist specialising in quantum optics and the theory of open quantum systems. He is the Dan Walls Professor of Physics at the University of Auckland and a principal investigator of the Dodd-Walls Centre. Carmichael has played a role in the development of the field of quantum optics and is particularly known for his Quantum Trajectory Theory (QTT) which offers a more detailed view of quantum behaviour by making predictions of single events happening to individual quantum systems. Carmichael works with experimental groups around the world to apply QTT to experiments on single quantum systems, including those contributing to the development of quantum computers. He is a Fellow of Optical Society of America, the American Physical Society and the Royal Society of New Zealand. He was awarded the Max Born Award in 2003, the Humboldt Research Award in 1997 and the Dan Walls Medal of the New Zealand Institute of Physics in 2017. In 2015, he was recognised as an Outstanding Referee by the American Physical Society.
Biography and education
Carmichael was born in Manchester England on January 17, 1950 and emigrated to New Zealand. He gained a BSc in physics and mathematics in 1971, and an MSc in physics in 1973 at the University of Auckland. It was here that Carmichael met New Zealand physicist Dan Walls, who supervised Carmichael's MSc in Auckland, and later his PhD at the University of Waikato from 1972 to 1977. Having just returned from PhD and postdoctoral studies with Roy Glauber at Harvard University and Hermann Haken at the University of Stuttgart, Walls brought the rapidly growing field of Quantum Optics to New Zealand, established a major research centre with an active strategy of collaborating with quantum optics groups around the world. During Carmichael's PhD studies, he and Walls made seminal contributions to the theoretical foundations of quantum optics. He then travelled to the United States for further postgraduate studies.
After post-doctoral positions at the City University of New York, and at the University of Texas at Austin (1979–1981) Carmichael was appointed as an assistant professor and later associate professor at the University of Arkansas. He was a visiting scientist at the Royal Signal and Radar Establishment in Malvern in 1984, visiting professor at the University of Texas at Austin in 1988 and at Caltech in 1989. In 1989 he was made associate professor, and in 1991 full professor, at the University of Oregon. He returned to New Zealand in 2002 to join the University of Auckland, becoming the inaugural Dan Walls Professor of Physics, a position he still holds today.
Research
Carmichael has made seminal contributions to the field of quantum optics and open quantum systems over more than four decades. He is known particularly for his development of quantum trajectory theory (1993), which offers a way to describe the evolution of a quantum system as it interacts with its environment. In 1993 he developed (at the same time as a separate formulation by Crispin Gardiner) the theory and application of cascaded quantum systems, in which the optical output of one quantum system becomes the optical input for another quantum system. He has also contributed to advances in the theory of nonclassical light and quantum correlation, quantum optical measurements, quantum fluctuations and noise in radiative processes, nonlinear physics and multi-photon processes, cavity quantum electrodynamics, quantum statistical methods and quantum entanglement.