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Primeur weekly 2019-03-11

Focus

Interview with EuroHPC JU interim executive director Gustav Kalbe ...

Quantum computing

9,1 million euro for trinational quantum research ...

IBM achieves highest quantum volume to date and establishes roadmap for reaching quantum advantage ...

Microsoft Quantum Team is announcing the Microsoft Quantum Network ...

Los Alamos National Laboratory upgrades to D-Wave 2000Q quantum computer ...

New hurdle cleared in race toward quantum computing ...

Focus on Europe

Hyperion Research invites submissions for HPC Innovation Excellence Awards ...

Optalysys launches world's first commercial optical processing system, the FT:X 2000 ...

SDSC's Research Data Services to host first U.S. GO FAIR Office ...

Intel to support the Irish Centre for High End Computing on new collaborative quantum computing project ...

New simulation methods to visualise quantum effects in superfluid fermions ...

Middleware

International team to organize 2019 survey of MPI usages ...

Energy Laboratory chooses Qumulo's file storage for its computational science centre ...

Hardware

Mellanox showcases live system demonstrations of LinkX 200G & 400G cables and transceivers at OFC 2019 ...

Alan D. George named Interim Director of the Pittsburgh Supercomputing Center ...

ScaleMP and AMD announce strategic collaboration for scale-up EPYC servers ...

NVIDIA to acquire Mellanox for $6,9 billion ...

Air Force Research Laboratory introduces new sharable supercomputing capability for classified research ...

Applications

High CO2 levels can destabilize marine layer clouds ...

Using supercomputers to checkmate cancer ...

Revealing the role of neutron stars in gravitational wave discoveries ...

UC San Diego scientists computationally model chemical realities of water ...

TACC assists in massive data collection effort in lung development to help premature babies ...

New AI tool revolutionizes process for matching cancer patients with clinical trials ...

Raph Hix models the inner workings of supernovae on the world’s most powerful supercomputers ...

EPFL researchers simulate the process of adhesive wear ...

The Cloud

Oracle participates in National Science Foundation Cloud for scientific research project ...

New hurdle cleared in race toward quantum computing


A new device created by Purdue physicists has experimentally shown quasiparticles interfering for the first time. Purdue University photo/James Nakamura.
4 Mar 2019 West Lafayette - Qubits, the units used to encode information in quantum computing, are not all created equal. Some researchers believe that topological qubits, which are tougher and less susceptible to environmental noise than other kinds, may be the best medium for pushing quantum computing forward.

Quantum physics deals with how fundamental particles interact and sometimes come together to form new particles called quasiparticles. Quasiparticles appear in fancy theoretical models, but observing and measuring them experimentally has been a challenge. With the creation of a new device that allows researchers to probe interference of quasiparticles, we may be one giant leap closer. The findings were published inNature Physics.

"We're able to probe these particles by making them interfere", stated Michael Manfra, the Bill and Dee O'Brian Chair Professor of Physics and Astronomy at Purdue University. "People have been trying to do this for a long time, but there have been major technical challenges."

To study particles this small, Michael Manfra's group builds teeny, tiny devices using a crystal growth technique that builds atomic layer by atomic layer, called molecular beam epitaxy. The devices are so small that they confine electrons to two dimensions. Like a marble rolling around on a tabletop, they can't move up or down.

If the device, or "tabletop", is clean and smooth enough, what dominates the physics of the experiment is not electrons' individual actions, but how they interact with each other. To minimize the individual energy of particles, Michael Manfra's team cooled them down to extremely low temperatures - around minus-460 degrees Fahrenheit. Additionally, the electrons were subjected to a large magnetic field. Under these three conditions: extremely cold temperatures, confined to two dimensions, and exposed to a magnetic field, really strange physics starts to happen. Physicists call this the fractional quantum hall regime.

"In these exotic conditions, electrons can arrange themselves so that the basic object looks like it carries one-third of an electron charge", stated Michael Manfra, who is also a professor of materials engineering, and electrical and computer engineering. "We think of elementary particles as either bosons or fermions, depending on the spin of the particle, but our quasiparticles have a much more complex behaviour as they evolve around each other. Determining the charge and statistical properties of these states is a long-standing challenge in quantum physics."

To make the particles interfere, Michael Manfra's group built an interferometer: a device that merges two or more sources of quasiparticles to create an interference pattern. If you threw two stones into a pond, and their waves intersected at some point, this is where they would generate interference and the patterns would change.

But replicating these effects on a much smaller scale is extremely difficult. In such a cramped space, electrons tend to repel each other, so it costs additional energy to fit another electron into the space. This tends to mess up the interference effects so researchers can't see them clearly.

The Purdue interferometer overcomes this challenge by adding metallic plates only 25 nanometers away from the interfering quasiparticles. The metallic plates screen out the repulsive interactions, reducing energy cost and allowing interference to occur.

The new device has identical walls on each side and metal gates, somewhat like a pinball machine. But unlike a pinball, which scatters around chaotically, the electrons in this device follow a very strict pattern.

"The magic of the quantum hall effect is that all of the current will travel on the edge of the sample, not through the middle", stated James Nakamura, a Ph.D. candidate at Purdue and lead author of the paper. "When quasiparticles are tunneled across the beam splitter, they're split in half, in a quantum mechanical sense. That happens twice, at two beam splitters, and interference occurs between the two different paths."

In such a bizarre realm of physics, it can be difficult for researchers to know if what they think they're seeing is what they're actually seeing. But these results show that, potentially for the first time, researchers have witnessed the quantum mechanical interference of quasiparticles.

This mechanism could also help in the development of topological qubits down the road.

"As far as we know, this is the only viable platform for trying to do more complex experiments that may, in more complicated states, be the basis of a topological qubit", Michael Manfra stated. "We've been trying to build these for a while, with the end goal of validating some of these very strange properties. We're not all the way there yet, but we have shown this is the best way forward."

This research was supported by the Department of Energy, W. M. Keck Foundation and Nokia Bell Labs.
Source: Purdue University

Back to Table of contents

Primeur weekly 2019-03-11

Focus

Interview with EuroHPC JU interim executive director Gustav Kalbe ...

Quantum computing

9,1 million euro for trinational quantum research ...

IBM achieves highest quantum volume to date and establishes roadmap for reaching quantum advantage ...

Microsoft Quantum Team is announcing the Microsoft Quantum Network ...

Los Alamos National Laboratory upgrades to D-Wave 2000Q quantum computer ...

New hurdle cleared in race toward quantum computing ...

Focus on Europe

Hyperion Research invites submissions for HPC Innovation Excellence Awards ...

Optalysys launches world's first commercial optical processing system, the FT:X 2000 ...

SDSC's Research Data Services to host first U.S. GO FAIR Office ...

Intel to support the Irish Centre for High End Computing on new collaborative quantum computing project ...

New simulation methods to visualise quantum effects in superfluid fermions ...

Middleware

International team to organize 2019 survey of MPI usages ...

Energy Laboratory chooses Qumulo's file storage for its computational science centre ...

Hardware

Mellanox showcases live system demonstrations of LinkX 200G & 400G cables and transceivers at OFC 2019 ...

Alan D. George named Interim Director of the Pittsburgh Supercomputing Center ...

ScaleMP and AMD announce strategic collaboration for scale-up EPYC servers ...

NVIDIA to acquire Mellanox for $6,9 billion ...

Air Force Research Laboratory introduces new sharable supercomputing capability for classified research ...

Applications

High CO2 levels can destabilize marine layer clouds ...

Using supercomputers to checkmate cancer ...

Revealing the role of neutron stars in gravitational wave discoveries ...

UC San Diego scientists computationally model chemical realities of water ...

TACC assists in massive data collection effort in lung development to help premature babies ...

New AI tool revolutionizes process for matching cancer patients with clinical trials ...

Raph Hix models the inner workings of supernovae on the world’s most powerful supercomputers ...

EPFL researchers simulate the process of adhesive wear ...

The Cloud

Oracle participates in National Science Foundation Cloud for scientific research project ...