World record: German supercomputer simulates quantum computer

March 31, 2010

A quantum computer could provide an enormous improvement in the processing speed of existing computers. However, as yet they only exist in the laboratory in the form of small prototypes with a capacity of a few bits. They can now be explored in more detail, at least in simulations. The Jülich supercomputer JUGENE can now simulate the largest quantum computer system in the world with 42 bits.

"The of a quantum computer grows exponentially with its size," says Prof. Dr. Kristel Michielsen from the Jülich Supercomputing Centre, Germany. "This is both an enormous opportunity for future applications and also a great challenge for simulations at the moment." If a quantum computer is expanded by just one single computer bit then its computing power is immediately doubled due to the laws of on which it is based. The computing power of a only grows linearly with its components. Ten percent more transistors (in the ideal case) also only means ten percent more performance.

If you want to simulate a quantum computer using present computing power then you soon come up against limits. For a quantum computer with 42 computer bits you need machines like the Jülich JUGENE, which is the fastest computer in Europe with almost 300,000 processors and a computing power of 1015 floating point operations per second. Shor's algorithm, a common test application for quantum computers, has been demonstrated on the 42-bit quantum computer, factorizing 15707 into 113x139. This is a number that is thousands of times larger than those factorized on quantum computers that have been experimentally realized in the past.

For the world record, the Jülich research team and the Computational Physics group of the University of Groningen in the Netherlands developed the to such a level that it can run efficiently on this large number of processors. "If so many processors have to work together then in the case of simple algorithms it can easily happen that processors are waiting for each other and thus performance is lost," says Michielsen. "Our software is optimized so that thousands of processors can work seamlessly together. It scales almost perfectly." Scaling is the term computer experts use to describe the property of software of converting more processors one-to-one into more power, that is to say faster results. Scalability will also play an increasingly important part in the multi-core processors of PCs.

On the basis of the simulation software that has now been developed, it will be possible to explore in detail the phenomena and dynamics of quantum-mechanical systems. Whereas today's laboratory prototypes have only reached a size of eight bits, simulation can be used to efficiently investigate the properties of larger systems. In particular, simulations make it possible to test the impact of external influences on the sensitive quantum system and to discover how to compensate for resulting errors, providing valuable findings for laboratory experiments.

Explore further: Quantum Computer Science on the Internet

Related Stories

Quantum Computer Science on the Internet

July 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 ...

New supercomputer to be unveiled

February 12, 2007

A Canadian firm is claiming to have taken a quantum leap in technology by producing a computer that can perform 64,000 calculations at once.

12-qubits reached in quantum information quest

May 8, 2006

In the drive to understand and harness quantum effects as they relate to information processing, scientists in Waterloo and Massachusetts have benchmarked quantum control methods on a 12-Qubit system. Their research was performed ...

'Self-correcting' gates advance quantum computing

March 12, 2009

( -- Two Dartmouth researchers have found a way to develop more robust “quantum gates,” which are the elementary building blocks of quantum circuits. Quantum circuits, someday, will be used to operate quantum ...

Discovery could pave the way for quantum computing

March 18, 2010

( -- Two experimental systems at the forefront of modern physics research -- a single trapped ion and a quantum atomic gas -- have been combined for the first time by researchers at Cambridge.

Recommended for you

Carefully crafted light pulses control neuron activity

November 17, 2017

Specially tailored, ultrafast pulses of light can trigger neurons to fire and could one day help patients with light-sensitive circadian or mood problems, according to a new study in mice at the University of Illinois.

Strain-free epitaxy of germanium film on mica

November 17, 2017

Germanium, an elemental semiconductor, was the material of choice in the early history of electronic devices, before it was largely replaced by silicon. But due to its high charge carrier mobility—higher than silicon by ...

New imaging technique peers inside living cells

November 16, 2017

To undergo high-resolution imaging, cells often must be sliced and diced, dehydrated, painted with toxic stains, or embedded in resin. For cells, the result is certain death.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Mar 31, 2010
I am somewhat dubious about the value of this work, no doubt it is of the highest calibre but what does it tell us that we don't aleady know?, are there potential unkowns in the probabilistic interactions of the quantum bits when they scale up?

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.