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 A better way to weigh millions of solitary stars
15.12.2017 | Vanderbilt University

nachricht A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg

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: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>