Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

HP researchers propose new path to optical quantum computing

04.07.2005


Researchers from HP Laboratories in Bristol, UK, have proposed an approach to distributed optical quantum computing with a technique that is highly efficient, flexible and scalable.



Quantum computing is expected to be much more powerful than conventional information processing. It should be able to search faster and simulate better, factor large numbers efficiently and virtually guarantee secure communications.

Optical quantum computing – using photons instead of electrons for computation – is one possible approach to quantum computing. The technology might still be several decades away from practical implementation.


The researchers – Dr Bill Munro and Dr Tim Spiller, of HP Labs Bristol, with Professor Kae Nemoto, of the National Institute of Informatics (NII), Tokyo – have proposed an approach that generates interactions between photons by using so-called weak optical nonlinearities and intense laser fields. The result is the creation of two-photon gates, the basic building blocks of a quantum computer. They have published their results in the New Journal of Physics: (http://stacks.iop.org/1367-2630/7/137)

Normally, photons, the basic components of light, do not easily interact or ‘talk’ to each other. That is why multiple light signals carrying different information can be sent along a thin optical fibre without interfering with each other. But for quantum information processing and communication, it is vital that photons do interact when called upon to do so. The photons are the qubits – the basic information bits – in this model of a quantum computer.

Why use an optical quantum system rather than solid state? Dr Spiller points out that light can be used for both quantum computing and quantum communication at the same time, which would not be the case with a solid-state system, where “static” quantum information would have to be mapped onto light to communicate it. This means that the approach is suitable for distributed quantum computing, so that small but useful clusters of qubits can be physically separated – even at different sites – but linked together for computation.

The new approach uses weak nonlinearities and strong laser pulses to generate the interaction between the two individual photons. The laser pulse acts as an intermediary between the photons, first ‘talking’ to one, then the other, so that the two photons become entangled. In quantum processing, generally attempting to check on the state of entangled qubits leads to the collapse of the information they carry. But with the HP-NII team’s approach, only the information in the laser pulse collapses; the qubit photons become entangled through this collapse.

Dr Spiller describes single photons – in fact any kind of qubit – as “precious” and points out that optical quantum computing systems that have previously been proposed would need hundreds of them to operate at all. And most of those photons would be wasted. The HP-NII system operates with single photons and wastes none. This makes it much more practical and efficient for quantum information and communication because today, single photons are hard to generate.

At the heart of the system is a single-photon detector – an innovation proposed by the HP Labs team – that is also used as a single-photon source. This is used to generate photons on demand.

The scheme is reliable because the communication between separated quantum processing sites can be mediated by robust laser pulses rather than fragile single photon qubits.

Dr Munro said: “Our approach provides the fundamental building blocks for quantum computation, including highly efficient non-absorbing single-photon detectors, two-qubit parity detectors, near deterministic CNOT gates and more. All these elements are essential quantum information processing devices.” The approach is open for experimentalists to test.

HP Labs is one of the leading corporate research institutions with activities in the field of quantum science. As a global IT company, it is important for HP to be involved in such far-reaching research in quantum information processing, which could have a significant impact on information and communication technology in the future.

Julian Richards | alfa
Further information:
http://www.hp.com
http://stacks.iop.org/1367-2630/7/137

More articles from Physics and Astronomy:

nachricht Breaking the optical bandwidth record of stable pulsed lasers
24.01.2017 | Institut national de la recherche scientifique - INRS

nachricht European XFEL prepares for user operation: Researchers can hand in first proposals for experiments
24.01.2017 | European XFEL GmbH

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>