John Martinis, Google/UCSB
Department of Physics & Astronomy Colloquium
Science & Engineering Research Facility (SERF)
February 17, 2020
Refreshments – 3:00
Colloquium – 3:30
The promise of quantum computers is that certain computational tasks might be executed exponentially faster on a quantum processor than on a classical processor. A fundamental challenge is to build a high-fidelity processor capable of running quantum algorithms in an exponentially large computational space. Here we report the use of a processor with programmable superconducting qubits to create quantum states on 53 qubits, corresponding to a computational state-space of dimension 253 (about 1016). Measurements from repeated experiments sample the resulting probability distribution, which we verify using classical simulations. Our Sycamore processor takes about 200 seconds to sample one instance of a quantum circuit a million times—our benchmarks currently indicate that the equivalent task for a state-of-the-art classical supercomputer would take approximately 10,000 years. This dramatic increase in speed compared to all known classical algorithms is an experimental realization of quantum supremacy for this specific computational task, heralding a much-anticipated computing paradigm.
John M. Martinis attended the University of California at Berkeley from 1976 to 1987, where he received two degrees in Physics: B.S. (1980) and Ph.D. (1987). His thesis research focused on macroscopic quantum tunneling in Josephson Junctions. After completing a post-doctoral position at the Commisiariat Energie Atomic in Saclay, France, he joined the Electromagnetic Technology division at NIST in Boulder. At NIST he was involved in understanding the basic physics of the Coulomb Blockade, and worked to use this phenomenon to make a new fundamental electrical standard based on counting electrons. While at NIST he also invented series-array SQUID amplifiers. In 1993 he started an effort building high-resolution x-ray microcalorimeters based on superconducting sensors and series-array SQUIDs. This effort has grown to include applications in x-ray microanalysis and astrophysics, and optical and infrared astronomy. More recently he started a project to build a new fundamental standard of temperature based on noise thermometry, and in 2001 he helped initiate a project to use a microcalorimeter optical photon counter with high quantum efficiency for quantum communications. Since 2002 his research effort has focused on building a quantum computer using Josephson junctions. He has pioneer many important demonstrations, including entangled states, Bell state violation, Fock and arbitrary photon generation, photon NOON states, and the quantum von Neumannn and RezQu architecture. In 2010, he was awarded with collaborator Andrew Cleland the “Science breakthrough of the year” for the first demonstration of the quantum ground state in a mechanical oscillator system. In 2014 he was awarded the London Prize for low-temperature physics research on superconducting quantum bits. Dr. Martinis was a NIST Fellow, and is a Fellow of the American Physical Society. At the University of California, Santa Barbara he currently holds the Wooster Chair in experimental physics. In 2014 he was awarded the London Prize for his pioneering work on superconducting qubits. In 2014, Dr. Martinis joined Google to head up their quantum-hardware effort. The aim of this research is to build the first useful quantum computer.