Featured Research

from universities, journals, and other organizations

Light finds the right mix: Quickly switching orientation of a laser beam enables control over quantum properties of light

Date:
December 4, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Classical computers process data as a series of ones and zeros known as bits; in contrast, quantum computers encode information into the physical properties of an information unit known as a quantum bit, or qubit. Two or more qubits are then able to link together to speed up the processing efficiency, enabling quantum computers to tackle mathematical problems beyond the capability of conventional machines. However, reliably creating the precise multiple qubits required for quantum-computer protocols remains a challenge.

Classical computers process data as a series of ones and zeros known as bits; in contrast, quantum computers encode information into the physical properties of an information unit known as a quantum bit, or qubit. Two or more qubits are then able to link together to speed up the processing efficiency, enabling quantum computers to tackle mathematical problems beyond the capability of conventional machines. However, reliably creating the precise multiple qubits required for quantum-computer protocols remains a challenge.

Related Articles


Individual packets of light -- photons -- are quantum mechanical systems that could act as qubits. A photon stores information in its polarization -- the plane in which its associated electric field oscillates. Recently, Leonid Krivitsky at the A*STAR Data Storage Institute in Singapore and co‐workers demonstrated a technique that can create pairs of photons within a broad class of quantum states1.

"The ability to generate well-controlled quantum states of light is essential for quantum optics and quantum information experiments," says Krivitsky. "Whereas methods are well developed for generating arbitrary pure states of photons, there are limited approaches to creating mixed states."

Krivitsky and co-workers started by aiming a linearly polarized laser beam at a crystal. The nonlinear optical properties of the target meant that the incoming light generated pairs of photons in a quantum state known as a Bell state. The photons paired in a Bell state are either both horizontal or both vertical, with equal probability. Two such Bell states are achievable depending on the polarization of the laser light.

The researchers controlled the laser light using a device known as a liquid crystal retarder (LCR), which can quickly rotate optical polarization. By changing the shape of the voltage driving the LCR, the researchers blended the two Bell states into mixed states of any desired purity and entanglement.

Preparation of a quantum state with a specific mixture of probabilities of horizontal or vertical photons is crucial for some quantum algorithms, but previous approaches have involved complicated optical equipment. "Our method does not require a sophisticated optical setup," says Krivitsky. "It is versatile -- it can be plugged into any existing setup -- and is insensitive to mechanical vibrations."

The team is now working to find an equally simple detection method so that the results of a quantum calculation can be 'read out'. "We are developing an advanced protocol that can directly and quickly characterize these mixed states," says Krivitsky.


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Jibo Dai, Yink Loong Len, Yong Siah Teo, Leonid A Krivitsky, Berthold-Georg Englert. Controllable generation of mixed two-photon states. New Journal of Physics, 2013; 15 (6): 063011 DOI: 10.1088/1367-2630/15/6/063011

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Light finds the right mix: Quickly switching orientation of a laser beam enables control over quantum properties of light." ScienceDaily. ScienceDaily, 4 December 2013. <www.sciencedaily.com/releases/2013/12/131204090802.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, December 4). Light finds the right mix: Quickly switching orientation of a laser beam enables control over quantum properties of light. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2013/12/131204090802.htm
The Agency for Science, Technology and Research (A*STAR). "Light finds the right mix: Quickly switching orientation of a laser beam enables control over quantum properties of light." ScienceDaily. www.sciencedaily.com/releases/2013/12/131204090802.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Blu-Ray Discs Getting Second Run As Solar Panels

Blu-Ray Discs Getting Second Run As Solar Panels

Newsy (Nov. 26, 2014) Researchers at Northwestern University are repurposing Blu-ray movies for better solar panel technology thanks to the discs' internal structures. Video provided by Newsy
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins