Solving big problems with new quantum algorithm

Nov 09, 2009
Solving big problems

(PhysOrg.com) -- In a recently published paper, Aram Harrow at the University of Bristol and colleagues from MIT in the United States have discovered a quantum algorithm that solves large problems much faster than conventional computers can.

One of the most basic problems in maths is solving very large linear equations. There's nothing mysterious about them, they simply take time and the more variables there are, the longer it takes. Even a supercomputer would struggle to solve a system of equations that has a trillion variables.

However, in a new paper recently published in , Aram Harrow at the University of Bristol and colleagues from MIT in the United States have discovered a quantum algorithm that solves the problem much faster than conventional computers can. And the larger the problem, the greater the speedup.

To understand how the quantum algorithm works, think of a digital equaliser in a stereo CD player. The equaliser needs to amplify some components of the signal and attenuate others. Ordinary equalisers employ classical computer algorithms that treat each component of the sound one at a time.

By contrast, a quantum equaliser could employ a quantum algorithm that treats all components together at once (a trick called 'quantum parallelism'). The result is a huge reduction in the difficulty of signal processing.

“Large-scale linear systems of equations exist in many fields, such as weather prediction, engineering, and computer vision”, says Harrow. “Quantum computers could supply serious improvements for these and many other problems. For example, a trillion-variable problem would take a classical computer at least a hundred trillion steps to solve, but using the new algorithm, a quantum computer could solve the problem in just a few hundred steps”.

The solution could also be applied to other complex processes such as image and video processing, genetic analyses and even Internet traffic control.

More information: Quantum Algorithm for Linear Systems of Equations, Phys. Rev. Lett. 103, 150502 (2009), DOI:10.1103/PhysRevLett.103.150502

Provided by University of Bristol (news : web)

Explore further: Quantum physics just got less complicated

add to favorites email to friend print save as pdf

Related Stories

Quantum computing may actually be useful, after all

Oct 09, 2009

(PhysOrg.com) -- In recent years, quantum computers have lost some of their luster. In the 1990s, it seemed that they might be able to solve a class of difficult but common problems — the so-called NP-complete ...

Quantum computer solves problem, without running

Feb 22, 2006

By combining quantum computation and quantum interrogation, scientists at the University of Illinois at Urbana-Champaign have found an exotic way of determining an answer to an algorithm – without ever running ...

Quantum Computer Science on the Internet

Jul 31, 2004

A simulated quantum computer went online on the Internet last month. With the ability to control 31 quantum bits, it is the most powerful of its type in the world. Software engineers can use it to test algorithms that might o ...

Taking Computers to the Quantum Level

May 09, 2006

“If Moore’s Law holds for another 10-15 years,” says Dr. Raymond Laflamme, “we’ll have transistors the size of atoms.” Laflamme is a physicist at the University of Waterloo in Ontario, Canada. He ...

Ion trap quantum computing

May 12, 2009

(PhysOrg.com) -- “Right now, classical computers are faster than quantum computers,” René Stock tells PhysOrg.com. “The goal of quantum computing is to eventually speed up the time scale of solving certain import ...

Recommended for you

Quantum physics just got less complicated

Dec 19, 2014

Here's a nice surprise: quantum physics is less complicated than we thought. An international team of researchers has proved that two peculiar features of the quantum world previously considered distinct ...

Controlling light on a chip at the single-photon level

Dec 16, 2014

Integrating optics and electronics into systems such as fiber-optic data links has revolutionized how we transmit information. A second revolution awaits as researchers seek to develop chips in which individual ...

Fraud-proof credit cards possible with quantum physics

Dec 15, 2014

Credit card fraud and identify theft are serious problems for consumers and industries. Though corporations and individuals work to improve safeguards, it has become increasingly difficult to protect financial ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.