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Primeur weekly 2016-11-07

Focus

EGI to finalize service catalogue and ISO certification ...

Exascale supercomputing

SLAC and Berkeley Lab researchers prepare for scientific computing on the exascale ...

Quantum computing

Researchers nearly reached quantum limit with nanodrums ...

Focus on Europe

New approach for ARM-based technology to halve the cost of powering data centres ...

PRACE to award contracts in third and final phase of Pre-Commercial Procurement (PCP) ...

PRACE welcomes new Managing Director Serge Bogaerts ...

PRACE 2016 Digest Special Edition on Industry is out ...

Supercomputer comes up with a profile of dark matter ...

Middleware

Bright Computing supplies Bright OpenStack to Stony Brook University ...

DDN Annual High Performance Computing Trends survey reveals rising deployment of flash tiers and private/hybrid Clouds versus public for HPC ...

With Corral 3, TACC provides a more unified data structure and increased space ...

Hardware

Mellanox launches open source software initiative for routers, load balancers, and firewalls ...

Mellanox Multi-Host technology reshapes data centre economics ...

Cray awarded $26 million contract from the Department of Defense High Performance Computing Modernization Programme ...

Hewlett Packard Enterprise completes acquisition of SGI ...

Centre for Modelling & Simulation in Bristol launches new supercomputer ...

Baylor University selects Cray CS400 cluster supercomputer to power innovative research ...

SGI awarded $27 million systems contract with the Army Research Laboratory Defense Supercomputing Resource Center ...

Applications

XSEDE spins off annual conference to unite research computing community ...

Researchers at UCSB explore the delicate balance between coherence and control with a simple but complete platform for quantum processing ...

Cosmic connection: KITP's Greg Huber worked with nuclear physicists to confirm a structural similarity found in both human cells and neutron stars ...

New technique for creating NV-doped nanodiamonds may be boost for quantum computing ...

New bacteria groups, and stunning diversity, discovered underground ...

The Cloud

IBM drives Cloud storage with new all-flash and software defined solutions ...

Capital markets firms continue to invest in hardware for compute Grids alongside growing Cloud adoption, according to TABB Group Research ...

Researchers at UCSB explore the delicate balance between coherence and control with a simple but complete platform for quantum processing


This image shows members of the John Martinis quantum computing group (l to r): Charles Neill, Pedram Roushan, Anthony Megrant and John Martinis. Credit: Matt Perko.
31 Oct 2016 Santa Barbara - If you're building a quantum computer with the intention of making calculations not even imaginable with today's conventional technology, you're in for an arduous effort. Case in point: You're delving into new problems and situations associated with the foundational work of novel and complicated systems as well as cutting-edge technology.

Such is life for the scientists of the Martinis Group at UC Santa Barbara and Google Inc., as they explore the exciting but also still somewhat counter-intuitive world of quantum computing. In a paper published in the journalNature Physics, they and colleagues at Tulane University in New Orleans demonstrate a relatively simple yet complete platform for quantum processing, integrating the control of three superconducting qubits.

"We're probing the edge of our capability", stated the paper's lead author, Pedram Roushan. There have been quite a few efforts to build and study individual parts of a quantum processor, he explained, but this particular project involves putting them all together in a basic building block that can be fully controlled and potentially scaled up into a functional quantum computer.

However, before a fully practicable quantum computer - with all its potential for vast, rapid and simultaneous calculations - can be made, various and sometimes unpredictable and spontaneous circumstances arise that have to be understood as the researchers pursue greater control and sophistication of their system.

"You're dealing with particles - qubits in this case - that are interacting with one another, and they're interacting with external fields", Pedram Roushan stated. "This all leads to very complicated physics."

To help solve this particular many-body problem, he explained, their fully controllable quantum processing system had to be built from a single qubit up, in order to give the researchers opportunities to more clearly understand the states, behaviors and interactions that can occur.

By engineering the pulse sequences used to manipulate the spins of the photons in their system, the researchers created an artificial magnetic field affecting their closed loop of three qubits, causing the photons to interact strongly with not only each other, but also with the pseudo-magnetic field. Not a small feat.

"Naturally most systems where there is good control are photonic systems", stated co-author Charles Neill. Unlike electrons, charge-less photons generally tend not to interact with each other nor with external magnetic fields, he explained. "In this article we show that we can get them to interact with each other very strongly, and interact with a magnetic field very strongly, which are the two things you need to do to get them to do interesting physics with photons", Charles Neill stated.

Another advantage of this synthetic condensed-matter system is the ability to drive it into its lowest-lying energy state - called the ground state - to probe its properties.

But with more control comes the potential for more decoherence. As the researchers strove for greater programmability and ability to influence and read the qubits, the more open their system was likely to be to error and loss of information.

"The more control we have over a quantum system, the more complex algorithms we would be able to run", stated co-author Anthony Megrant. "However, every time we add a control line, we're also introducing a new source of decoherence." At the level of a single qubit, a tiny margin of error may be tolerated, the researchers explained, but even with a relatively small increase in the number of qubits, the potential for error multiplies exponentially.

"There are these corrections that are intrinsically quantum mechanical, and then they start to matter at the level of precision that we're getting at", Charles Neill stated.

To combat the potential for error while increasing their level of control, the team had to reconsider both the architecture of their circuit and the material that was being used in it. Instead of their traditionally single-level, planar layout, the researchers redesigned the circuit to allow control lines to "cross over" others via a self-supporting metallic "bridge." The dielectric - the insulating material between the conducting control wires - was itself found to be a major source of errors.

"All deposited dielectrics that we know of are very lossy", Anthony Megrant stated, and so a more precisely fabricated and less defective substrate was brought in to minimize the likelihood of decoherence.

Progress is incremental but solid, according to the researchers, who continue to explore the true potential of their quantum system. Add to that delicate dance speed, which is essential for the kind of performance they want to see in a fully operational quantum computer. Slow speeds reduce control errors but make the system more vulnerable to coherence limits and defects imposed by the materials. Fast speeds avoid the influence of defects in the material but reduce the amount of control the operators have over the system, they said.

With this platform, however, scaling up will be a reality of the not-too-distant future, they said.

"If we can control these systems very precisely - maybe at the level of 30 qubits or so - we can get to the level of doing computations that no conventional computer can do", Pedram Roushan stated.

Source: University of California - Santa Barbara

Back to Table of contents

Primeur weekly 2016-11-07

Focus

EGI to finalize service catalogue and ISO certification ...

Exascale supercomputing

SLAC and Berkeley Lab researchers prepare for scientific computing on the exascale ...

Quantum computing

Researchers nearly reached quantum limit with nanodrums ...

Focus on Europe

New approach for ARM-based technology to halve the cost of powering data centres ...

PRACE to award contracts in third and final phase of Pre-Commercial Procurement (PCP) ...

PRACE welcomes new Managing Director Serge Bogaerts ...

PRACE 2016 Digest Special Edition on Industry is out ...

Supercomputer comes up with a profile of dark matter ...

Middleware

Bright Computing supplies Bright OpenStack to Stony Brook University ...

DDN Annual High Performance Computing Trends survey reveals rising deployment of flash tiers and private/hybrid Clouds versus public for HPC ...

With Corral 3, TACC provides a more unified data structure and increased space ...

Hardware

Mellanox launches open source software initiative for routers, load balancers, and firewalls ...

Mellanox Multi-Host technology reshapes data centre economics ...

Cray awarded $26 million contract from the Department of Defense High Performance Computing Modernization Programme ...

Hewlett Packard Enterprise completes acquisition of SGI ...

Centre for Modelling & Simulation in Bristol launches new supercomputer ...

Baylor University selects Cray CS400 cluster supercomputer to power innovative research ...

SGI awarded $27 million systems contract with the Army Research Laboratory Defense Supercomputing Resource Center ...

Applications

XSEDE spins off annual conference to unite research computing community ...

Researchers at UCSB explore the delicate balance between coherence and control with a simple but complete platform for quantum processing ...

Cosmic connection: KITP's Greg Huber worked with nuclear physicists to confirm a structural similarity found in both human cells and neutron stars ...

New technique for creating NV-doped nanodiamonds may be boost for quantum computing ...

New bacteria groups, and stunning diversity, discovered underground ...

The Cloud

IBM drives Cloud storage with new all-flash and software defined solutions ...

Capital markets firms continue to invest in hardware for compute Grids alongside growing Cloud adoption, according to TABB Group Research ...