John M. Martinis

Last updated
John M. Martinis
Alma mater University of California, Berkeley (B.S., Ph.D.)
Awards Fritz London Memorial Prize, 2014 [1] John Stewart Bell Prize, 2021 [2]
Scientific career
Thesis Macroscopic quantum tunneling and energy-level quantization in the zero voltage state of the current-biased Josephson junction [3]  (1985)
Doctoral advisor John Clarke [3]

John M. Martinis (born 1958) is an American physicist and a professor of physics at the University of California, Santa Barbara. In 2014, the Google Quantum A.I. Lab announced that it had hired Martinis and his team in a multimillion dollar deal to build a quantum computer using superconducting qubits. [4]

Career

John Martinis (2017)

John M. Martinis received his B.S. in physics in 1980 and his Ph.D. in physics from the University of California, Berkeley. During his Ph.D., he investigated the quantum behaviour of a macroscopic variable, the phase difference across a Josephson tunnel junction. [5]

He joined the Commissariat à l'Energie Atomique in Saclay, France, for a first postdoc and then the Electromagnetic Technology division at NIST in Boulder, where he worked on superconducting quantum interference devices (SQUIDs) amplifiers. [6] While at NIST he developed a technique of X-ray detection by using a superconducting transition-edge sensor microcalorimeter with electrothermal feedback. [7]

Since 2002 he has been working with Josephson-Junction qubits with the aim of building the first quantum computer. [8]

In 2004 he moved to the University of California Santa Barbara, where he held the Worster Chair in experimental physics until 2017. In 2014, Martinis' team was hired by Google to build the first useful quantum computer. [8]

On October 23, 2019, Martinis and his team published a paper on Nature with title "Quantum supremacy using a programmable superconducting processor", [9] where they presented how they achieved quantum supremacy (hereby disproving the extended Church–Turing thesis) for the first time using a 53-qubits quantum computer. [10] In April 2020, Wired magazine announced that Martinis reportedly resigned from Google after being reassigned to an advisory role. [11] On September 29, 2020, it was announced that Martinis had moved to Australia to join Silicon Quantum Computing, a start-up founded by Professor Michelle Simmons. [12]

In 2021, he received the John Stewart Bell Prize for Research on Fundamental Issues in Quantum Mechanics and Their Applications. [2]

Related Research Articles

<span class="mw-page-title-main">Quantum computing</span> Technology that uses quantum mechanics

A quantum computer is a computer that takes advantage of quantum mechanical phenomena.

<span class="mw-page-title-main">SQUID</span> Type of magnetometer

A SQUID is a very sensitive magnetometer used to measure extremely weak magnetic fields, based on superconducting loops containing Josephson junctions.

This is a timeline of quantum computing.

The magnetic flux, represented by the symbol Φ, threading some contour or loop is defined as the magnetic field B multiplied by the loop area S, i.e. Φ = B ⋅ S. Both B and S can be arbitrary, meaning Φ can be as well. However, if one deals with the superconducting loop or a hole in a bulk superconductor, the magnetic flux threading such a hole/loop is quantized. The (superconducting) magnetic flux quantumΦ0 = h/(2e) ≈ 2.067833848...×10−15 Wb is a combination of fundamental physical constants: the Planck constant h and the electron charge e. Its value is, therefore, the same for any superconductor. The phenomenon of flux quantization was discovered experimentally by B. S. Deaver and W. M. Fairbank and, independently, by R. Doll and M. Näbauer, in 1961. The quantization of magnetic flux is closely related to the Little–Parks effect, but was predicted earlier by Fritz London in 1948 using a phenomenological model.

<span class="mw-page-title-main">Josephson effect</span> Quantum physical phenomenon

In physics, the Josephson effect is a phenomenon that occurs when two superconductors are placed in proximity, with some barrier or restriction between them. It is an example of a macroscopic quantum phenomenon, where the effects of quantum mechanics are observable at ordinary, rather than atomic, scale. The Josephson effect has many practical applications because it exhibits a precise relationship between different physical measures, such as voltage and frequency, facilitating highly accurate measurements.

<span class="mw-page-title-main">Charge qubit</span> Superconducting qubit implementation

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 utilize superconducting architecture.

<span class="mw-page-title-main">Flux qubit</span> Superconducting qubit implementation

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.

<span class="mw-page-title-main">D-Wave Systems</span> Canadian quantum computing company

A macroscopic quantum state is a state of matter in which macroscopic properties, such as mechanical motion, thermal conductivity, electrical conductivity and viscosity, can be described only by quantum mechanics rather than merely classical mechanics. This occurs primarily at low temperatures where little thermal motion is present to mask the quantum nature of a substance.

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.

The superconducting tunnel junction (STJ) — also known as a superconductor–insulator–superconductor tunnel junction (SIS) — is an electronic device consisting of two superconductors separated by a very thin layer of insulating material. Current passes through the junction via the process of quantum tunneling. The STJ is a type of Josephson junction, though not all the properties of the STJ are described by the Josephson effect.

Macroscopic quantum phenomena are processes showing quantum behavior at the macroscopic scale, rather than at the atomic scale where quantum effects are prevalent. The best-known examples of macroscopic quantum phenomena are superfluidity and superconductivity; other examples include the quantum Hall effect and topological order. Since 2000 there has been extensive experimental work on quantum gases, particularly Bose–Einstein condensates.

Superconducting logic refers to a class of logic circuits or logic gates that use the unique properties of superconductors, including zero-resistance wires, ultrafast Josephson junction switches, and quantization of magnetic flux (fluxoid). As of 2023, superconducting computing is a form of cryogenic computing, as superconductive electronic circuits require cooling to cryogenic temperatures for operation, typically below 10 kelvin. Often superconducting computing is applied to quantum computing, with an important application known as superconducting quantum computing.

<span class="mw-page-title-main">Robert J. Schoelkopf</span> American physicist

Robert J. Schoelkopf III is an American physicist, most noted for his work on quantum computing as one of the inventors of superconducting qubits. 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. 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.

<span class="mw-page-title-main">Michel Devoret</span> French physicist at Yale University

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.

<span class="mw-page-title-main">Yasunobu Nakamura</span> Japanese physicist

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.

In quantum computing, quantum supremacy or quantum advantage is the goal of demonstrating that a programmable quantum computer can solve a problem that no classical computer can solve in any feasible amount of time, irrespective of the usefulness of the problem. The term was coined by John Preskill in 2012, but the concept dates back to Yuri Manin's 1980 and Richard Feynman's 1981 proposals of quantum computing.

<span class="mw-page-title-main">Sergio Boixo</span> Spanish physicist

Sergio Boixo has degrees in computer engineering, philosophy, mathematics, and master and PhD in physics, and is best known for his work on quantum computing. He is currently working as Chief Scientist Quantum Computer Theory for Google's Quantum Artificial Intelligence Lab, a team he joined in 2013, shortly after its foundation.

Dale J. Van Harlingen is an American condensed matter physicist.

References

  1. ↑ "Fritz London Memorial Prize". phy.duke.edu. Retrieved 21 April 2020.
  2. 1 2 "John Stewart Bell Prize" . Retrieved 3 May 2021.
  3. 1 2 "Physics Tree - John M. Martinis". academictree.org. Retrieved 21 April 2020.
  4. ↑ Finley, Klint (2014-09-05). "The Man Who Will Build Google's Elusive Quantum Computer". Wired. ISSN   1059-1028 . Retrieved 2019-11-02.
  5. ↑ Clarke, J.; Cleland, A. N.; Devoret, M. H.; Esteve, D.; Martinis, J. M. (1988-02-26). "Quantum mechanics of a macroscopic variable: the phase difference of a josephson junction". Science. 239 (4843): 992–997. doi:10.1126/science.239.4843.992. ISSN   0036-8075. PMID   17815701. S2CID   1732678.
  6. ↑ Welty, Richard P.; Martinis, John M. (March 1993). "Two-stage integrated SQUID amplifier with series array output". IEEE Transactions on Applied Superconductivity. 3: 2605–2608. doi:10.1109/77.233523. ISSN   1051-8223. S2CID   33500389.
  7. ↑ Irwin, K. D.; Hilton, G. C.; Wollman, D. A.; Martinis, John M. (1998-08-05). "X‐ray detection using a superconducting transition‐edge sensor microcalorimeter with electrothermal feedback". Applied Physics Letters. 69 (13): 1945. doi:10.1063/1.117630. ISSN   0003-6951.
  8. 1 2 "Google AI John Martinis". ai.google. Retrieved 2019-11-03.
  9. ↑ Arute, Frank; Arya, Kunal; Babbush, Ryan; Bacon, Dave; Bardin, Joseph C.; Barends, Rami; Biswas, Rupak; Boixo, Sergio; Brandao, Fernando G. S. L.; Buell, David A.; Burkett, Brian (October 2019). "Quantum supremacy using a programmable superconducting processor". Nature. 574 (7779): 505–510. arXiv: 1910.11333 . doi: 10.1038/s41586-019-1666-5 . ISSN   1476-4687. PMID   31645734.
  10. ↑ "Shtetl-Optimized » Blog Archive » Quantum supremacy: the gloves are off". 23 October 2019. Retrieved 2019-11-04.
  11. ↑ "Google's Head of Quantum Computing Hardware Resigns". Wired. ISSN   1059-1028 . Retrieved 2020-04-21.
  12. ↑ "Ex-Google quantum chief joins Simmons' silicon startup". InnovationAus. 2020-09-29. Retrieved 2020-09-29.
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