Robert J. Schoelkopf | |
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![]() Schoelkopf in 2014 | |
Born | 1964 |
Alma mater | |
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Awards |
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Scientific career | |
Fields | Condensed matter |
Institutions | Yale University |
Doctoral advisor | Thomas G. Phillips |
Doctoral students | Jerry M. Chow |
Other notable students | Andreas Wallraff, Jay Gambetta, |
Robert J. Schoelkopf III (born January 24, 1964) is an American physicist, most noted for his work on quantum computing as one of the inventors of superconducting qubits. [2] Schoelkopf's main research areas are quantum transport, single-electron devices, and charge dynamics in nanostructures. His research utilizes quantum-effect and single-electron devices, both for fundamental physical studies and for applications. Techniques often include high-speed, high-sensitivity measurements performed on nanostructures at low temperatures. [3] Schoelkopf serves as director of the Yale Center for Microelectronic Materials and Structures and as associate director of the Yale Institute for Nanoscience and Quantum Engineering. Since 2014, Schoelkopf is also the Director of the Yale Quantum Institute. He is Professor of Physics and Sterling Professor of Applied Physics at Yale University. [4] The title of Sterling Professor is the highest honor bestowed upon Yale faculty.
Schoelkopf was born in Manhattan, New York City, the son of art dealer and Hudson River School expert Robert J. Schoelkopf II. [5] Schoelkopf received his A.B. in physics from Princeton University, cum laude, in 1986, and his Ph.D. from Caltech in 1995. [6] From 1986 to 1988 he was an electrical/cryogenic engineer in the Laboratory for High-Energy Astrophysics at NASA’s Goddard Space Flight Center, where he developed low-temperature radiation detectors and cryogenic instrumentation for future space missions. He came to Yale as a postdoctoral researcher in the group of Daniel Prober in 1995.
Moving to Yale University, he was from 1995 to 1998 a lecturer and associate research scientist, advancing to assistant professor in 1998, and professor of applied physics and physics in 2003. He was later awarded the titles Sterling Professor of Applied Physics and Physics and William A. Norton Professor of Applied Physics and Physics. [3] [6]
Schoelkopf was a visiting professor at the University of New South Wales in Australia in 2008. He has been an invited lecturer at universities and professional organizations throughout the United States and in Canada and Europe. Schoelkopf was a semi-finalist for Discover magazine's Technological Innovation of the Year in 1999. His other honors include NASA's Technical Innovator Award. He is a fellow of the American Association for the Advancement of Science and the American Physical Society.
He became the William A. Norton Professor at Yale in 2013 and the Sterling Professor of Applied Physics and Physics.
Schoelkopf was elected to the National Academy of Sciences in 2015. [7] His other honors include Fellow in the American Physical Society and Fellow of the American Association for the Advancement of Science.
Robert Schoelkopf focuses his research on the development of superconducting devices for quantum information processing, which might eventually lead to revolutionary advances in computing.
In 2007, a team of scientists led by Schoelkopf and Steven Girvin made a major breakthrough in quantum computing when it engineered a superconducting communication "bus" to store and transfer information between distant quantum bits, or qubits, on a chip. Their work is the first step to making the fundamentals of quantum computing useful. In 2009, their team demonstrated the first electronic quantum processor which could perform a quantum computation.
Schoelkopf's techniques emphasize high-speed, high-sensitivity measurements performed on nanostructures at low temperatures. Together with his former supervisor Daniel Prober and his laboratory team, Schoelkopf invented the Radio-Frequency Single-Electron Transistor, an electrometer capable of measuring sub-electron charges on nano-second timescales. This new transistor allowed them to study electrical transport at the single-charge level in various systems. They also developed new types of sensors and detectors that employ these capabilities.
Schoelkopf's current research focus, together with Michel Devoret and Steven Girvin of the Yale Department of Applied Physics, is to further develop superconducting circuits that might one day lead to a practical quantum computer. Other projects are directed at developing "hybrid" quantum systems based on integrating cold atoms, molecules, or electrons with solid-state circuits.
In quantum computing technology, roughly every three years, quantum decoherence has been improved by a factor of 10. It is the quantum computing analogue of Moore's law. [2] [8] [9]
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Quantum error correction (QEC) is used in quantum computing to protect quantum information from errors due to decoherence and other quantum noise. Quantum error correction is theorised as essential to achieve fault tolerant quantum computing that can reduce the effects of noise on stored quantum information, faulty quantum gates, faulty quantum preparation, and faulty measurements. This would allow algorithms of greater circuit depth.
In quantum computing, a charge qubit is a qubit whose basis states are charge states. In superconducting quantum computing, a charge qubit is formed by a tiny superconducting island coupled by a Josephson junction to a superconducting reservoir. The state of the qubit is determined by the number of Cooper pairs that have tunneled across the junction. In contrast with the charge state of an atomic or molecular ion, the charge states of such an "island" involve a macroscopic number of conduction electrons of the island. The quantum superposition of charge states can be achieved by tuning the gate voltage U that controls the chemical potential of the island. The charge qubit is typically read-out by electrostatically coupling the island to an extremely sensitive electrometer such as the radio-frequency single-electron transistor.
Superconducting quantum computing is a branch of solid state quantum computing that implements superconducting electronic circuits using superconducting qubits as artificial atoms, or quantum dots. For superconducting qubits, the two logic states are the ground state and the excited state, denoted respectively. Research in superconducting quantum computing is conducted by companies such as Google, IBM, IMEC, BBN Technologies, Rigetti, and Intel. Many recently developed QPUs use superconducting architecture.
In physics, quantum acoustics is the study of sound under conditions such that quantum mechanical effects are relevant. For most applications, classical mechanics are sufficient to accurately describe the physics of sound. However very high frequency sounds, or sounds made at very low temperatures may be subject to quantum effects.
In quantum computing, more specifically in superconducting quantum computing, flux qubits are micrometer sized loops of superconducting metal that is interrupted by a number of Josephson junctions. These devices function as quantum bits. The flux qubit was first proposed by Terry P. Orlando et al. at MIT in 1999 and fabricated shortly thereafter. During fabrication, the Josephson junction parameters are engineered so that a persistent current will flow continuously when an external magnetic flux is applied. Only an integer number of flux quanta are allowed to penetrate the superconducting ring, resulting in clockwise or counter-clockwise mesoscopic supercurrents in the loop to compensate a non-integer external flux bias. When the applied flux through the loop area is close to a half integer number of flux quanta, the two lowest energy eigenstates of the loop will be a quantum superposition of the clockwise and counter-clockwise currents. The two lowest energy eigenstates differ only by the relative quantum phase between the composing current-direction states. Higher energy eigenstates correspond to much larger (macroscopic) persistent currents, that induce an additional flux quantum to the qubit loop, thus are well separated energetically from the lowest two eigenstates. This separation, known as the "qubit non linearity" criteria, allows operations with the two lowest eigenstates only, effectively creating a two level system. Usually, the two lowest eigenstates will serve as the computational basis for the logical qubit.
A quantum bus is a device which can be used to store or transfer information between independent qubits in a quantum computer, or combine two qubits into a superposition. It is the quantum analog of a classical bus.
In quantum computing, and more specifically in superconducting quantum computing, the phase qubit is a superconducting device based on the superconductor–insulator–superconductor (SIS) Josephson junction, designed to operate as a quantum bit, or qubit.
Steven M. Girvin is an American physicist who is the Eugene Higgins Professor of Physics at Yale University and who served as deputy provost for research at Yale from 2007 to 2017. Girvin is noted for his theoretical work on quantum many body systems such as the fractional quantum Hall effect, and as co-developer of circuit QED, the application of the ideas of quantum optics to superconducting microwave circuits. Circuit QED is now the leading architecture for construction of quantum computers based on superconducting qubits.
In quantum computing, and more specifically in superconducting quantum computing, a transmon is a type of superconducting charge qubit designed to have reduced sensitivity to charge noise. The transmon was developed by Robert J. Schoelkopf, Michel Devoret, Steven M. Girvin, and their colleagues at Yale University in 2007. Its name is an abbreviation of the term transmission line shunted plasma oscillation qubit; one which consists of a Cooper-pair box "where the two superconductors are also [capacitively] shunted in order to decrease the sensitivity to charge noise, while maintaining a sufficient anharmonicity for selective qubit control".
In quantum mechanics, the cat state, named after Schrödinger's cat, is a quantum state composed of two diametrically opposed conditions at the same time, such as the possibilities that a cat is alive and dead at the same time.
Coplanar waveguide is a type of electrical planar transmission line which can be fabricated using printed circuit board technology, and is used to convey microwave-frequency signals. On a smaller scale, coplanar waveguide transmission lines are also built into monolithic microwave integrated circuits.
Michel Devoret is a French physicist and F. W. Beinecke Professor of Applied Physics at Yale University. He also holds a position as the Director of the Applied Physics Nanofabrication Lab at Yale. He is known for his pioneering work on macroscopic quantum tunneling, and the single-electron pump as well as in groundbreaking contributions to initiating the fields of circuit quantum electrodynamics and quantronics.
Yasunobu Nakamura (中村 泰信 Nakamura Yasunobu) is a Japanese physicist. He is a professor at the University of Tokyo's Research Center for Advanced Science and Technology (RCAST) and the Principal Investigator of the Superconducting Quantum Electronics Research Group (SQERG) at the Center for Emergent Matter Science (CEMS) within RIKEN. He has contributed primarily to the area of quantum information science, particularly in superconducting quantum computing and hybrid quantum systems.
Irfan Siddiqi is an American physicist and currently a professor of physics at the University of California, Berkeley and a faculty scientist at Lawrence Berkeley National Laboratory (LBNL). He currently is the director of the Quantum Nanoelectronics Laboratory at UC Berkeley and the Advanced Quantum Testbed at LBNL. Siddiqi is known for groundbreaking contributions to the field of superconducting quantum circuits, including dispersive single-shot readout of superconducting quantum bits, quantum feedback, observation of single quantum trajectories, and near-quantum limited microwave frequency amplification. In addition to other honors, for his pioneering work in superconducting devices, he was awarded with the American Physical Society George E. Valley, Jr. Prize in 2006, "for the development of the Josephson bifurcation amplifier for ultra-sensitive measurements at the quantum limit." Siddiqi is a fellow of the American Physical Society and a recipient of the UC Berkeley Distinguished Teaching Award in 2016.
Andreas Wallraff is a German physicist who conducts research in quantum information processing and quantum optics. He has taught as a professor at ETH Zürich in Zürich, Switzerland since 2006. He worked as a research scientist with Robert J. Schoelkopf at Yale University from 2002 to 2005, during which time he performed experiments in which the coherent interaction of a single photon with a single quantum electronic circuit was observed for the first time. His current work at ETH Zürich focuses on hybrid quantum systems combining superconducting electronic circuits with semiconductor quantum dots and individual Rydberg atoms as well as quantum error correction with superconducting qubits.
Jerry M. Chow is a physicist who conducts research in quantum information processing. He has worked as the manager of the Experimental Quantum Computing group at the IBM Thomas J. Watson Research Center in Yorktown Heights, New York since 2014 and is the primary investigator of the IBM team for the IARPA Multi-Qubit Coherent Operations and Logical Qubits programs. After graduating magna cum laude with a B.A. in physics and M.S. in applied mathematics from Harvard University, he went on to earn his Ph.D. in 2010 under Robert J. Schoelkopf at Yale University. While at Yale, he participated in experiments in which superconducting qubits were coupled via a cavity bus for the first time and two-qubit algorithms were executed on a superconducting quantum processor.
Quantum gate teleportation is a quantum circuit construction where a gate is applied to target qubits by first applying the gate to an entangled state and then teleporting the target qubits through that entangled state.
Katherine E. Aidala is an American physicist. She is a professor of physics at Mount Holyoke College and a Fellow of the American Physical Society. She studies the fundamental properties of materials and devices, providing insight that could lead to technological innovation.
Jeremy Levy is an American physicist who is a Distinguished Professor of Physics at the University of Pittsburgh.
Andrew A. Houck is an American physicist, quantum information scientist, and professor of electrical and computer engineering at Princeton University. He is director of the Co-Design Center for Quantum Advantage, a national research center funded by the U.S. Department of Energy Office of Science, as well as co-director of the Princeton Quantum Initiative. His research focuses on superconducting electronic circuits to process and store information for quantum computing and to simulate and study many-body physics. He is a pioneer of superconducting qubits.