... A quantum computer with a mere 50 qubits would outclass the most powerful supercomputers in the world today. Surpassing the limits set by conventional computing, known as achieving quantum supremacy, has been a difficult road. Now, a team of physicists at the University of California Santa Barbara (UCSB) and Google have demonstrated a proof-of-principle for a quantum computer that may mean quantum supremacy is only months away....Two weeks after that piece in Futurism we saw this at New Scientist:
Google’s quantum computing plans threatened by IBM curveball
...IBM has come up with a way to simulate quantum computers that have 56 quantum bits, or qubits, on a non-quantum supercomputer – a task previously thought to be impossible. The feat moves the goalposts in the fight for quantum supremacy, the effort to outstrip classical computers using quantum ones.Well, at ten weeks old that's ancient history.
It used to be widely accepted that a classical computer cannot simulate more than 49 qubits because of memory limitations. The memory required for simulations increases exponentially with each additional qubit.
The closest anyone had come to putting the 49-qubit limit to a test was a 45-qubit simulation at the Swiss Federal Institute of Technology in Zurich, which needed 500 terabytes of memory. IBM’s new simulation upends the assumption by simulating 56 qubits with only 4.5 terabytes....
From Next Big Future, December 30:
Progress to turning silicon transistors into qubits which could enable billion qubit quantum computers
Japanese RIKEN researchers are trying to adapt existing the silicon metal–oxide–semiconductor field-effect transistors (MOSFETs) to integrate qubits with current electronics, offering the potential for scaling up quantum devices and bringing quantum computing closer to becoming a reality.Of course, with that "having been reported over x days ago"..... which partly explains our lead-in to Saturday's "Cryptography and Quantum Computers":
Keiji Ono and colleagues from the RIKEN Center for Emergent Matter Science and the Toshiba Corporation in Japan, in collaboration with researchers from the United States, are investigating the properties of qubits produced by imperfections or defects in silicon MOSFETs. In particular, they are exploring their potential for developing quantum computing devices that are compatible with current manufacturing technologies.
“Companies like IBM and Google are developing quantum computers that use superconductors,” explains Ono. “In contrast, we are attempting to develop a quantum computer based on the silicon manufacturing techniques currently used to make computers and smart phones. The advantage of this approach is that it can leverage existing industrial knowledge and technology.”
After cooling a silicon MOSFET to 1.6 kelvin (−271.6 degrees Celsius), the researchers measured its electrical properties while applying a magnetic field and a microwave field. They found that when the silicon MOSFET was neither fully turned on nor off, a pair of defects in the silicon MOSFET formed two quantum dots in close vicinity to each other. This ‘double quantum dot’ generated qubits from the spin of electrons in the dots. It also produced quantum effects that can be used to control these qubits....MORE
The author seems optimistic - note headline - but I'm not so sure....Some of last year's more popular Quantum computing posts:
From Nautil.us:
How Classical Cryptography Will Survive Quantum Computers
Nov. 5
Questions America Wants Answered: "Is Quantum Computing an Existential Threat to Blockchain Technology?"
July 26
Yeah, I Got Your Bitcoin Right Here: "‘Quantum Checks’ to Replace Cryptocurrencies in the Future?"
July 11
Computing: Will Quantum Devices Outperform Classical Computers by Year-end 2017? (thus achieving 'quantum supremecy')
April 6
The route to high-speed quantum computing is paved with error
March 8
"Google's Quantum AI Laboratory set out investment opportunities on the road to the ultimate quantum machines" (GOOG).
