John Morrissey Doyle | |
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Education | B.S., Electrical Engineering Ph.D., Physics |
Alma mater | Massachusetts Institute of Technology |
Occupation(s) | Atomic physicist and academic |
Known for | Cold molecule physics, EDM searches |
Awards | Humboldt Research Award (2003) JSPS Fellowship (2005) Herbert P. Broida Prize (2021) Norman F. Ramsey Prize (2024) |
Scientific career | |
Fields | Physics |
Institutions | Harvard University |
Thesis | Energy Distribution Measurements of Magnetically Trapped Spin-Polarized Hydrogen: Evaporative Cooling and Surface Sticking (1991) |
Doctoral advisor | Thomas J. Greytak and Daniel Kleppner |
John Morrissey Doyle is an American physicist working in the field of Atomic, Molecular, and Optical (AMO) physics and Precision Particle Physics. He is the Henry B. Silsbee Professor of Physics, Director of the Japanese Undergraduate Research Exchange Program (JUREP), Co-Director of the Harvard Quantum Initiative as well as Co-director of the Ph.D. Program in Quantum Science and Engineering at Harvard University. [1]
Doyle is most known for his work on cooling and trapping of atoms and molecules as well as for his contributions to the spectroscopy and quantum control of trapped atomic and molecular ensembles. The work of the Doyle group and its collaborators has been contributing to research in AMO (Atomic, Molecular, and Optical) and low-energy elementary particle physics, with implications for molecular structure elucidations, quantum information, and explorations beyond the Standard Model of physics. [2] He is a Fellow of the Fulbright Program and the Japanese Society for the Promotion of Science (JSPS).
Doyle received the Alexander von Humboldt Research Award in 2003 and was the recipient of the 2021 Broida Award and the 2024 Norman F. Ramsey Prize of the American Physical Society (APS). [3] [4] In 2022, he was elected to the presidential line of the APS, and has been serving as APS Vice President. [5]
Doyle obtained his bachelor’s degree in Electrical Engineering from the Massachusetts Institute of Technology (MIT) in 1986 and his Ph.D. in Physics in 1991, likewise from MIT. He stayed on as a postdoctoral associate from 1991 to 1993. [6]
Doyle joined Harvard University as an Assistant Professor in 1993, was promoted to John L. Loeb Associate Professor of the Natural Sciences in 1997, and was appointed as a Professor of Physics in 1999. Since 2015, he has been the Henry B. Silsbee Professor of Physics at Harvard University [7] and since 2019 a Visiting Professor at Okayama University. [8]
Doyle was a Founding Co-Director of Center for Ultracold Atoms, a National Science Foundation Physics Frontier Center from 2000 to 2020 [9] and the Founding Director of the Harvard Quantum Optics Center from 2010 to 2017. Since 2006, he has been serving as the Founder and Director of the Japan-US Undergraduate Research Exchange Program (JUREP) and is a founding Co-director of the Ph.D. Program in Quantum Science and Engineering as well as the Harvard Quantum Initiative. [10]
He served as Guest Editor of a special issue of the European Physical Journal D on Cold Molecules (2004), of ChemPhysChem on Cold Molecules (2009), of Molecular Physics on Manipulation of Molecules via Electromagnetic Fields (2013), of the Journal of Molecular Spectroscopy on Laser Cooling of Molecules (2021) and of a Themed Collection of Physical Chemistry Chemical Physics (PCCP) on Quantum Computing and Quantum Information Storage (2021). [11]
The Doyle group has conducted research on atomic and molecular cooling techniques, such as buffer-gas cooling and the buffer-gas beam, as well as laser-cooling and trapping of molecules, including polyatomic, at ultracold temperatures. His research has involved laser and microwave detection and spectroscopy of molecules, investigation of atomic and molecular collisions, utilization of cold molecules for particle physics (especially the search for CP-violating physics beyond the Standard Model through EDM searches), and the development of new quantum information processing platforms using ultracold molecules confined in electromagnetic traps. In addition, the Doyle group developed a new technique for producing heavy, polar radical molecules in the cold and ultracold regime to search for new particles in the 10-100 TeV mass range. [1]
Doyle has made contributions to AMO physics in the context of quantum science. His research group developed a general technique for cooling and loading molecules into traps, combining cryogenic technology with laser-based cooling and control methods. The group has applied this technique to trap diatomic calcium monofluoride (CaF) molecules and more recently extended it to polyatomic molecules, demonstrating trapped linear calcium monohydroxide (CaOH) molecules and a beam of nonlinear calcium monomethoxide (CaOCH3) molecules, all at ultracold temperatures. [12] [13] In one of his highly cited studies, he demonstrated a loading technique for magnetic trapping of calcium monohydride (CaH) molecules at millikelvin temperatures, achieved via elastic collisions with cryogenic helium serving as a cold buffer gas, while employing Zeeman spectroscopy to precisely determine the quantity of trapped molecules and their temperature. [14] He also studied strong qubit-cavity coupling, and examined quantum information protocols and molecular bit coherence. [15] In addition, he has offered insights into the challenges of cooling molecules to their ground state, as well as the potential applications in fields such as quantum computing and precision measurement and particle physics. [16]
Doyle's research in the area of quantum computing includes methods for producing both diatomic and polyatomic molecules in optical tweezer arrays, [17] [18] demonstrating long rotational coherence times for CaF qubits based on the molecule's rotational states. He also co-proposed integrating isolated polar molecules with mesoscopic solid-state devices to achieve quantum-level control. [19] In addition, he and David Patterson developed a technique for detecting and quantifying chirality in gas-phase molecules using nonlinear resonant phase-sensitive microwave spectroscopy. [20]
In another line of work, Doyle and collaborators demonstrated the production of Bose-Einstein condensates of metastable helium using only buffer-gas loading into a magnetic trap combined with evaporative cooling. [21] With the group of Yoshihiro Takahashi at Kyoto University, he assisted with the production and study of quantum degenerate Bose-Fermi and Fermi-Fermi mixtures of Yb and Li atoms, achieving simultaneous quantum degeneracy in mixtures composed of alkali and alkaline-earth-like atoms Li and Yb. The Doyle group also pioneered the control of cold collisions using applied electromagnetic fields. [22] [23]
A major research interest of Doyle has been molecular collision processes. His investigation on the magnetically trapped imidogen (NH) molecules and their collisions with both 3He and 4He isotopes provided insights into the interplay between molecular structure and collisional energy transfer at low temperatures. [24] In collaboration with David Patterson and Edem Tsikata, he was able to observe larger (>5 atoms) molecules moving slowly at cold temperatures (<10 K), providing insights into the behavior of larger molecules under such conditions. [25] Moreover, by combining the techniques of Stark deceleration, magnetic trapping, and cryogenic buffer-gas cooling, he in collaboration with Jun Ye achieved the first experimental observation of cold collisions between two different species of state-selected neutral polar molecules. [26]
Together with David DeMille and Gerald Gabrielse as part of the ACME collaboration, Doyle made use of thorium monoxide (ThO) to measure the electron electric dipole moment (eEDM), achieving an upper limit of |d(e)| < 8.7 × 10-29 e·cm (90% confidence), significantly improving sensitivity and impacting extensions to the Standard Model at the multi-TeV scale. [27] The same team later achieved another improvement by about a factor of ten in the eEDM limit, |d(e)| < 1.1 × 10-29 e·cm (90% confidence). [28] This improved experimental limit on the electric dipole moment of the electron was enabled by using a buffer-gas beam of cold ThO molecules and measuring the spin precession of electrons subjected to a huge intramolecular electric field. [28] Meanwhile, he alongside his collaborators expanded the range of species for similar searched for eEDM by the highly sensitive YbOH and SrOH molecules. [29]
In the 1990s and 2000s, Doyle demonstrated buffer gas cooling for numerous atoms and small molecules, including VO, NH, CaF, CaH, and NH3. [30] His collaborative work introduced the technique of buffer-gas cooling and loading of atoms and molecules into magnetic traps, applicable to species trappable at buffer gas temperatures as low as 240 mK, [31] and also showed the direct loading and cooling of a thermal beam into a cryogenic helium buffer gas. [32] He further contributed to the development of a general cooling method using a novel beam-loaded buffer gas technique that could be applied to a wide range of molecules in a molecular beam to achieve translational temperatures under 6 K. [33]
In collaboration with David DeMille, Doyle developed a new form of molecular beam, known as the buffer gas beam. This was later followed by him and Patterson creating a new type of cold, slow molecular beam, the hydrodynamically enhanced cryogenic buffer gas beam (CBGB). [34] This technique produces molecular beams that are comparably cold to traditional techniques, but with a much lower velocity in the laboratory frame and a much higher brightness and flux, especially for molecular radicals. [35] The buffer gas beam has found applications in laser cooling of molecules, precision spectroscopy, and in fundamental physics experiments.
In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero, i.e., 0 K. Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which microscopic quantum-mechanical phenomena, particularly wavefunction interference, become apparent macroscopically. More generally, condensation refers to the appearance of macroscopic occupation of one or several states: for example, in BCS theory, a superconductor is a condensate of Cooper pairs. As such, condensation can be associated with phase transition, and the macroscopic occupation of the state is the order parameter.
Laser cooling includes several techniques where atoms, molecules, and small mechanical systems are cooled with laser light. The directed energy of lasers is often associated with heating materials, e.g. laser cutting, so it can be counterintuitive that laser cooling often results in sample temperatures approaching absolute zero. It is a routine step in many atomic physics experiments where the laser-cooled atoms are then subsequently manipulated and measured, or in technologies, such as atom-based quantum computing architectures. Laser cooling relies on the change in momentum when an object, such as an atom, absorbs and re-emits a photon. For example, if laser light illuminates a warm cloud of atoms from all directions and the laser's frequency is tuned below an atomic resonance, the atoms will be cooled. This common type of laser cooling relies on the Doppler effect where individual atoms will preferentially absorb laser light from the direction opposite to the atom's motion. The absorbed light is re-emitted by the atom in a random direction. After repeated emission and absorption of light the net effect on the cloud of atoms is that they will expand more slowly. The slower expansion reflects a decrease in the velocity distribution of the atoms, which corresponds to a lower temperature and therefore the atoms have been cooled. For an ensemble of particles, their thermodynamic temperature is proportional to the variance in their velocity, therefore the lower the distribution of velocities, the lower temperature of the particles.
Optical tweezers are scientific instruments that use a highly focused laser beam to hold and move microscopic and sub-microscopic objects like atoms, nanoparticles and droplets, in a manner similar to tweezers. If the object is held in air or vacuum without additional support, it can be called optical levitation.
Deborah Shiu-lan Jin was an American physicist and fellow with the National Institute of Standards and Technology (NIST); Professor Adjunct, Department of Physics at the University of Colorado; and a fellow of the JILA, a NIST joint laboratory with the University of Colorado.
Wolfgang Ketterle is a German physicist and professor of physics at the Massachusetts Institute of Technology (MIT). His research has focused on experiments that trap and cool atoms to temperatures close to absolute zero, and he led one of the first groups to realize Bose–Einstein condensation in these systems in 1995. For this achievement, as well as early fundamental studies of condensates, he was awarded the Nobel Prize in Physics in 2001, together with Eric Allin Cornell and Carl Wieman.
Lene Vestergaard Hau is a Danish physicist and educator. She is the Mallinckrodt Professor of Physics and of Applied Physics at Harvard University.
An optical lattice is formed by the interference of counter-propagating laser beams, creating a spatially periodic polarization pattern. The resulting periodic potential may trap neutral atoms via the Stark shift. Atoms are cooled and congregate at the potential extrema. The resulting arrangement of trapped atoms resembles a crystal lattice and can be used for quantum simulation.
Atom optics "refers to techniques to manipulate the trajectories and exploit the wave properties of neutral atoms". Typical experiments employ beams of cold, slowly moving neutral atoms, as a special case of a particle beam. Like an optical beam, the atomic beam may exhibit diffraction and interference, and can be focused with a Fresnel zone plate or a concave atomic mirror.
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David Edward Pritchard is a professor at the Massachusetts Institute of Technology (MIT) who specializes in atomic physics and educational research.
Atomtronics Atomtronics is the emerging quantum technology of matter-wave circuits which coherently guide propagating ultra-cold atoms. The systems typically include components analogous to those found in electronic, quantum electronics or optical systems, such as beam splitter, transistors, atomic counterpart of Superconducting Quantum Interference Devices (SQUIDs). Applications range from studies of fundamental physics to the development of practical devices.
David P. DeMille is an American physicist and Professor of Physics at the University of Chicago. He is best known for his use of polar diatomic molecules to search for symmetry-violating effects within the molecules and as a means for manipulating the external properties of the molecules.
Tilman Esslinger is a German experimental physicist. He is Professor at ETH Zurich, Switzerland, and works in the field of ultracold quantum gases and optical lattices.
Gerhard Rempe is a German physicist, Director at the Max Planck Institute of Quantum Optics and Honorary Professor at the Technical University of Munich. He has performed pioneering experiments in atomic and molecular physics, quantum optics and quantum information processing.
Bretislav Friedrich is a Research Group leader at the Department of Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft and Honorarprofessor at the Technische Universität in Berlin, Germany. He is globally recognized for his pioneering research surrounding interaction of molecules with and in electric, magnetic, and optical fields as well as on cold molecules. He was admitted to the Learned Society of the Czech Republic in 2011.
Heather Lewandowski is a professor of physics at the University of Colorado Boulder. She looks to understand the quantum mechanical processes in making chemical bonds. She uses time-varying inhomogeneous electric fields to achieve supersonic cooling. She also studies how students learn experimental skills in instructional physics labs and help to improve student learning in these environments. She is a Fellow of the American Physical Society.
Kate Page Kirby is an American physicist. From February 2015 to December 2020, Kirby was the chief executive officer of the American Physical Society (APS) and sits on the board of directors of the American Institute of Physics. Kate Kirby was elected a fellow of the American Physical Society (APS) in 1989 for her "innovative application of methods of quantum chemistry to the quantitative elucidation of a diverse range of molecular phenomena." She was made a fellow of the American Association for the Advancement of Science (AAAS) in 1996 for her contributions to physics.
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Tanya Zelevinsky is a professor of physics at Columbia University. Her research focuses on high-precision spectroscopy of cold molecules for fundamental physics measurements, including molecular lattice clocks, ultracold molecule photodissociation, as well as cooling and quantum state manipulation techniques for diatomic molecules with the goal of testing the Standard Model of particle physics. Zelevinsky graduated from MIT in 1999 and received her Ph.D. from Harvard University in 2004 with Gerald Gabrielse as her thesis advisor. Subsequently, she worked as a post-doctoral research associate at the Joint Institute for Laboratory Astrophysics (JILA) with Jun Ye on atomic lattice clocks. She joined Columbia University as an associate professor of physics in 2008. Professor Zelevinsky became a Fellow of the American Physical Society in 2018 and received the Francis M. Pipkin Award in 2019.
Silke Ospelkaus-Schwarzer is a German experimental physicist who studies ultra-cold molecular materials at the University of Hanover Institute of Quantum Optics. She was awarded a European Research Council Consolidator Award in 2022.
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