Google started working on a form of quantum computing that harnesses superconductivity in 2014. In 2017 or 2018 Google hopes to perform a computation that is beyond even the most powerful ‘classical’ supercomputers — an elusive milestone known as quantum supremacy. Its rival, Microsoft, is betting on an intriguing but unproven concept, topological quantum computing, and hopes to perform a first demonstration of the technology.
The quantum-computing start-up scene is also heating up. Christopher Monroe, co-founded the start-up IonQ in 2015, plans to begin hiring in earnest this year.
Physicist Robert Schoelkopf at Yale University in New Haven, Connecticut, who co-founded the start-up Quantum Circuits, and former IBM applied physicist Chad Rigetti, who set up Rigetti in Berkeley, California, say they expect to reach crucial technical milestones soon.
The largest trapped ion quantum computer with 20 qubits is being tested in an academic lab led by Rainer Blatt at the University of Innsbruck in Austria.
In 2016, Rainer Blatt’s and Peter Zoller’s research teams have simulated lattice gauge theories in a trapped ion quantum computer. Gauge theories describe the interaction between elementary particles, such as quarks and gluons, and they are the basis for our understanding of fundamental processes.
“Dynamical processes, for example, the collision of elementary particles or the spontaneous creation of particle-antiparticle pairs, are extremely difficult to investigate,” explains Christine Muschik, theoretical physicist at the IQOQI. “However, scientists quickly reach a limit when processing numerical calculations on classical computers. For this reason, it has been proposed to simulate these processes by using a programmable quantum system.”
The two leading approaches to quantum computers are superconducting loops or trapped ion.
Schoelkopf helped to pioneered superconducting loop quantum computers and which Google, IBM, Rigetti and Quantum Circuits have adopted. This involves encoding quantum states as oscillating currents in superconducting loops.
IonQ and several major academic labs, encode qubits in single ions held by electric and magnetic fields in vacuum traps.
John Martinis, who worked at the University of California, Santa Barbara, until Google hired him and his research group in 2014, says that the maturity of superconducting technology prompted his team to set the bold goal of quantum supremacy. The team plans to achieve this using a ‘chaotic’ quantum algorithm that produces what looks like a random output. If the algorithm is run on a quantum computer made of relatively few qubits, a classical machine can predict its output. But once the quantum machine gets close to about 50 qubits, even the largest classical supercomputers will fail to keep pace
IonQ aims to build trapped ion machines that have 32 or even 64 qubits. The ion-trap technology will enable their designs to be more flexible and scalable than superconducting circuits, he says.
The people running IonQ have industry heavyweights taking notice. The firm’s founders have received about $64 million in government research funding to date. After years of badgering the IonQ founders to step into the venture capital space, Weller helped put together a team from some of the highest reaches of government and business. At Weller’s urging, New Enterprise Associates made a $2 million investment to help the firm develop a marketable product.
Microsoft, meanwhile, is betting on the technology that has the most to prove. Topological quantum computing depends on excitations of matter that encode information by tangling around each other like braids. Information stored in these qubits would be much more resistant to outside disturbance than are other technologies and would, in particular, make error correction easier.
D-Wave Systems has led the market in selling the quantum computing systems. They sell adiabatic superconducting systems for about $10 million apiece.
SOURCES – Nature, Washington Post