Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Prototype chip could help make quantum computing practical: Built-in optics could enable chips that use trapped ions as quantum bits

Researchers from MIT and MIT Lincoln Laboratory report an important step toward practical quantum computers, with a paper describing a prototype chip that can trap ions in an electric field and, with built-in optics, direct laser light toward each of them.
Researchers from MIT and MIT Lincoln Laboratory report an important step toward practical quantum computers, with a paper describing a prototype chip that can trap ions in an electric field and, with built-in optics, direct laser light toward each of them.

Abstract:
Quantum computers are largely hypothetical devices that could perform some calculations much more rapidly than conventional computers can. Instead of the bits of classical computation, which can represent 0 or 1, quantum computers consist of quantum bits, or qubits, which can, in some sense, represent 0 and 1 simultaneously.

Prototype chip could help make quantum computing practical: Built-in optics could enable chips that use trapped ions as quantum bits

Cambridge, MA | Posted on August 9th, 2016

Although quantum systems with as many as 12 qubits have been demonstrated in the lab, building quantum computers complex enough to perform useful computations will require miniaturizing qubit technology, much the way the miniaturization of transistors enabled modern computers.

Trapped ions are probably the most widely studied qubit technology, but they've historically required a large and complex hardware apparatus. In today's Nature Nanotechnology, researchers from MIT and MIT Lincoln Laboratory report an important step toward practical quantum computers, with a paper describing a prototype chip that can trap ions in an electric field and, with built-in optics, direct laser light toward each of them.

"If you look at the traditional assembly, it's a barrel that has a vacuum inside it, and inside that is this cage that's trapping the ions. Then there's basically an entire laboratory of external optics that are guiding the laser beams to the assembly of ions," says Rajeev Ram, an MIT professor of electrical engineering and one of the senior authors on the paper. "Our vision is to take that external laboratory and miniaturize much of it onto a chip."

Caged in

The Quantum Information and Integrated Nanosystems group at Lincoln Laboratory was one of several research groups already working to develop simpler, smaller ion traps known as surface traps. A standard ion trap looks like a tiny cage, whose bars are electrodes that produce an electric field. Ions line up in the center of the cage, parallel to the bars. A surface trap, by contrast, is a chip with electrodes embedded in its surface. The ions hover 50 micrometers above the electrodes.

Cage traps are intrinsically limited in size, but surface traps could, in principle, be extended indefinitely. With current technology, they would still have to be held in a vacuum chamber, but they would allow many more qubits to be crammed inside.

"We believe that surface traps are a key technology to enable these systems to scale to the very large number of ions that will be required for large-scale quantum computing," says Jeremy Sage, who together with John Chiaverini leads Lincoln Laboratory's trapped-ion quantum-information-processing project. "These cage traps work very well, but they really only work for maybe 10 to 20 ions, and they basically max out around there."

Performing a quantum computation, however, requires precisely controlling the energy state of every qubit independently, and trapped-ion qubits are controlled with laser beams. In a surface trap, the ions are only about 5 micrometers apart. Hitting a single ion with an external laser, without affecting its neighbors, is incredibly difficult; only a few groups had previously attempted it, and their techniques weren't practical for large-scale systems.

Getting onboard

That's where Ram's group comes in. Ram and Karan Mehta, an MIT graduate student in electrical engineering and first author on the new paper, designed and built a suite of on-chip optical components that can channel laser light toward individual ions. Sage, Chiaverini, and their Lincoln Lab colleagues Colin Bruzewicz and Robert McConnell retooled their surface trap to accommodate the integrated optics without compromising its performance. Together, both groups designed and executed the experiments to test the new system.

"Typically, for surface electrode traps, the laser beam is coming from an optical table and entering this system, so there's always this concern about the beam vibrating or moving," Ram says. "With photonic integration, you're not concerned about beam-pointing stability, because it's all on the same chip that the electrodes are on. So now everything is registered against each other, and it's stable."

The researchers' new chip is built on a quartz substrate. On top of the quartz is a network of silicon nitride "waveguides," which route laser light across the chip. Above the waveguides is a layer of glass, and on top of that are the niobium electrodes. Beneath the holes in the electrodes, the waveguides break into a series of sequential ridges, a "diffraction grating" precisely engineered to direct light up through the holes and concentrate it into a beam narrow enough that it will target a single ion, 50 micrometers above the surface of the chip.

Prospects

With the prototype chip, the researchers were evaluating the performance of the diffraction gratings and the ion traps, but there was no mechanism for varying the amount of light delivered to each ion. In ongoing work, the researchers are investigating the addition of light modulators to the diffraction gratings, so that different qubits can simultaneously receive light of different, time-varying intensities. That would make programming the qubits more efficient, which is vital in a practical quantum information system, since the number of quantum operations the system can perform is limited by the "coherence time" of the qubits.

####

For more information, please click here

Contacts:
Abby Abazorius

617-253-2709

Copyright © Massachusetts Institute of Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Quantum Physics

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Possible Futures

Ben-Gurion University of the Negev researchers several steps closer to harnessing patient's own T-cells to fight off cancer June 6th, 2025

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Chip Technology

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Programmable electron-induced color router array May 14th, 2025

Enhancing power factor of p- and n-type single-walled carbon nanotubes April 25th, 2025

Ultrafast plasmon-enhanced magnetic bit switching at the nanoscale April 25th, 2025

Quantum Computing

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

Magnetism in new exotic material opens the way for robust quantum computers June 4th, 2025

A new study provides insights into cleaning up noise in quantum entanglement:When it comes to purifying quantum entanglement, new theoretical work highlights the importance of tailoring noise-minimizing solutions to specific quantum systems May 16th, 2025

Programmable electron-induced color router array May 14th, 2025

Optical computing/Photonic computing

Programmable electron-induced color router array May 14th, 2025

Nanophotonic platform boosts efficiency of nonlinear-optical quantum teleportation April 25th, 2025

Groundbreaking research unveils unified theory for optical singularities in photonic microstructures December 13th, 2024

UCF researcher discovers new technique for infrared “color” detection and imaging: The new specialized tunable detection and imaging technique for infrared photons surpasses present technology and may be a cost-effective method of capturing thermal imaging or night vision, medica December 13th, 2024

Discoveries

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Announcements

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Photonics/Optics/Lasers

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Following the folds – with quantum technology: The connection between a crumpled sheet of paper and quantum technology: A research team at the EPFL in Lausanne (Switzerland) and the University of Konstanz (Germany) uses topology in microwave photonics to make improved systems of May 16th, 2025

Programmable electron-induced color router array May 14th, 2025

Quantum nanoscience

A new study provides insights into cleaning up noise in quantum entanglement:When it comes to purifying quantum entanglement, new theoretical work highlights the importance of tailoring noise-minimizing solutions to specific quantum systems May 16th, 2025

Superconductors: Amazingly orderly disorder: A surprising effect was discovered through a collaborative effort by researchers from TU Wien and institutions in Croatia, France, Poland, Singapore, Switzerland, and the US during the investigation of a special material: the atoms are May 14th, 2025

Programmable electron-induced color router array May 14th, 2025

Unraveling the origin of extremely bright quantum emitters: Researchers from Osaka University have discovered the fundamental properties of single-photon emitters at an oxide/semiconductor interface, which could be crucial for scalable quantum technology February 28th, 2025

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project