Quantum computing with recycled particles

Oct 23, 2012

A research team from the University of Bristol's Centre for Quantum Photonics (CQP) have brought the reality of a quantum computer one step closer by experimentally demonstrating a technique for significantly reducing the physical resources required for quantum factoring.

The team have shown how it is possible to recycle the particles inside a quantum computer, so that quantum factoring can be achieved with only one third of the particles originally required. The research is published in the latest issue of .

Using as the particles, the Bristol team constructed a quantum optical circuit that recycled one of the photons to set a new record for factoring 21 with a - all previous demonstrations have factored 15.

Dr Anthony Laing, who led the project, said: "Quantum computers promise to harness the counterintuitive laws of to perform calculations that are forever out of reach of conventional classical computers. Realising such a device is one of the great technological challenges of the century."

While scientists and mathematicians are still trying to understand the full range of capabilities of quantum computers, the current driving application is the hard problem of factoring large numbers. The best classical computers can run for the lifetime of the universe, searching for the factors of a large number, yet still be unsuccessful.

In fact, Internet cryptographic protocols are based on this exponential overhead in computational time: if a third party wants to spy on your emails, they will need to solve a hard factoring problem first. A quantum computer, on the other hand, is capable of efficiently factoring large numbers, but the physical resources required mean that constructing such a device is highly challenging.

CQP PhD student Enrique Martín-López, who performed the experiment, said: "While it will clearly be some time before emails can be hacked with a quantum computer, this proof of principle experiment paves the way for larger implementations of quantum algorithms by using particle recycling."

Explore further: Deeper understanding of quantum fluctuations in 'frustrated' layered magnetic crystals

More information: Nature Photonics, 21 October 2012. doi:10.1038/nphoton.2012.259

add to favorites email to friend print save as pdf

Related Stories

Quantum interference fine-tuned by Berry phase

Jul 05, 2012

(Phys.org) -- A team from the University of Bristol’s Centre for Quantum Photonics (CQP) has experimentally demonstrated how to use Berry’s phase to accurately control quantum interference between different photons.

Physicists demonstrate that 15=3x5 about half of the time

Aug 19, 2012

Computing prime factors may sound like an elementary math problem, but try it with a large number, say one that contains more than 600 digits, and the task becomes enormously challenging and impossibly time-consuming. ...

Recommended for you

First glimpse inside a macroscopic quantum state

9 hours ago

In a recent study published in Physical Review Letters, the research group led by ICREA Prof at ICFO Morgan Mitchell has detected, for the first time, entanglement among individual photon pairs in a beam ...

Theory of the strong interaction verified

23 hours ago

The fact that the neutron is slightly more massive than the proton is the reason why atomic nuclei have exactly those properties that make our world and ultimately our existence possible. Eighty years after ...

3,000 atoms entangled with a single photon

Mar 25, 2015

Physicists from MIT and the University of Belgrade have developed a new technique that can successfully entangle 3,000 atoms using only a single photon. The results, published today in the journal Nature, repres ...

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.