Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Switching with a few photons for quantum computing

Provided/Gaeta Lab
Electron microscope photo of a cross-section of photonic bandgap fiber. Tiny glass tubes surrounding the core bend light waves in such a way that they interfere and cancel out, focusing all the energy of a beam into the hollow core.
Provided/Gaeta Lab

Electron microscope photo of a cross-section of photonic bandgap fiber. Tiny glass tubes surrounding the core bend light waves in such a way that they interfere and cancel out, focusing all the energy of a beam into the hollow core.

Abstract:
Quantum computing, where bits of information, or "qubits," are represented by the state of single atomic particles or photons of light, won't be of much use unless we can read the results. Cornell researchers have taken a step in that direction with a device that can measure the presence of just a few photons without disturbing them.

Switching with a few photons for quantum computing

Ithaca, NY | Posted on December 5th, 2012

The experiment mixes a strong beam of light with a very weak "signal" beam consisting of fewer than 20 photons in such a way that the phase -- a measure of the timing of a wave -- of the strong beam changes in proportion to the number of photons in the signal.

"Ideally what people want is to be able to measure the presence of a single photon, without destroying it," said Alex Gaeta, professor and director of applied and engineering physics. "Nevertheless, there are interesting quantum information algorithms you can do with just a few photons." Switching a light beam with a single photon would be the equivalent of a "gate" in a conventional electronic computer, where a 1 or 0 input switches the output between 1 and 0. In future applications this could communicate the state of a qubit in a quantum computer, or the photons themselves might be the qubits.

The device created by Gaeta's research group makes use of a new type of optical fiber known as photonic bandgap fiber, which consists of a hollow core surrounded by a honeycomb of tiny glass tubes. The honeycomb acts as a diffraction grating that bends light in such a way that all wavelengths are canceled except for a narrow gap at the fundamental wavelength of the light to be transported, confining that light to an intense beam in the core. The advantage over conventional glass fiber is that the core can be filled with a gas.

In experiments reported in the Dec. 2 online issue of the journal Nature Photonics, the researchers filled the core of a fiber about 9 centimeters long with rubidium vapor to exploit what's known as the Kerr effect, in which the oscillating electromagnetic fields in a beam of light interact with the electromagnetic fields of the electrons in atoms to change the refractive index of the medium, which changes the way light is affected when it passes through. The weak signal beam changes the refractive index of the rubidium vapor enough to change the phase of the strong beam, which can be measured after the beam emerges from the fiber. The process is "nondestructive" in that the number of photons in the signal beam is not affected.

Varying the intensity of the signal, and thereby the number of photons, the researchers measured a phase change of about .3 milliradians (a unit of angle) per photon, suggesting that eventually single photons could be detected, and that such a device could be used to count photons. Varying the length of pulses of the strong beam showed that the system could respond in less than 5 nanoseconds, indicating that the strong beam could be modulated at frequencies up to 50 MHz.

Similar measurements have been performed in apparatus cooled to cryogenic temperatures, the researchers noted, but this is the first time it has been done at room temperature.

The research was supported by the National Science Foundation.

####

For more information, please click here

Contacts:
Media Contact:
John Carberry
(607) 255-5553


Cornell Chronicle:
Bill Steele
(607) 255-7164

Copyright © Cornell University

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

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication July 13th, 2018

UMBC researchers develop nanoparticles to reduce internal bleeding caused by blast trauma July 13th, 2018

Govt.-Legislation/Regulation/Funding/Policy

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication July 13th, 2018

Carbon is the new black: Researchers use carbon nanotubes to develop clothing that can double as batteries July 10th, 2018

Quantum Computing

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

A refined magnetic sense: Algorithms and hardware developed in the context of quantum computation are shown to be useful for quantum-enhanced sensing of magnetic fields July 2nd, 2018

Carbon nanotube optics poised to provide pathway to optical-based quantum cryptography and quantum computing: Researchers are exploring enhanced potential of carbon nanotubes for unique applications June 18th, 2018

Evidence for a new property of quantum matter revealed: Electrical dipole activity detected in a quantum material unlike any other tested June 11th, 2018

Discoveries

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication July 13th, 2018

UMBC researchers develop nanoparticles to reduce internal bleeding caused by blast trauma July 13th, 2018

Announcements

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication July 13th, 2018

UMBC researchers develop nanoparticles to reduce internal bleeding caused by blast trauma July 13th, 2018

Photonics/Optics/Lasers

SUNY Poly-Led AIM Photonics and Partners Attend SEMICON West 2018 to Showcase High-Tech Advances, Collaboration, and Future R&D Opportunities: New York’s Tech Valley Makes a Major Showing in Silicon Valley July 3rd, 2018

Cleaning or Etching Items with Unique Geometries Requires Specialized Expertise June 27th, 2018

Powering the 21st Century with Integrated Photonics: UCSB-Led Team Selected for Demonstration of a Novel Waveguide Platform Which is Transparent Throughout the MWIR and LWIR Spectral Bands June 19th, 2018

Executives Explore Key Megatrends and Innovations in MEMS, Sensors, Imaging Tech at SEMI-MSIG European Summits: Speakers to share developments in smart automotive, smart cities, smart industrial, biomedical, consumer and IoT, September 19-21, 2018 in Grenoble, France June 19th, 2018

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