Feeds

Germans demo working quantum register

Qubits behave themselves impeccably

  • alert
  • submit to reddit

Build a business case: developing custom apps

Physicists at the University of Bonn have successfully demonstrated a five-qubit quantum register, using neutral atoms.

Registers are the central memory of a computer, in which information is stored in 1s and 0s. Neutral atoms are considered natural candidates for building a register because they can exist in an abundance of quantum states, and these individual states can be manipulated relatively simply. (Not to mention the fact that they can be counted – quite a useful property, when building a register.)

In Physical Review Letters, the researchers explain how they set up the register experimentally. You can access their paper here.

The team cooled five caesium atoms until they were almost stationary, and then loaded them into an optical lattice. An optical lattice is a light grid created by the interference of two or more laser beams. More poetically, it can be thought of as an "artificial crystal of light". In this particular case, the researchers loaded the atoms on to a so-called standing wave trap.

This lattice can trap the neutral atoms in potential wells because the electric fields of the lasers induce a dipole moment in the atom. Depending on the frequency of this dipole moment, and the frequency of the electric field, an atom will either be pushed into the areas of maximum light intensity, or into the areas of minimum light intensity.

Once the atoms were loaded onto the grid, the team initialised the register, that is, they set all the atoms to the state corresponding with 0 (zero). The team took photographs of the atoms in their potential wells using an intensified CCD camera. Then, using a polarised laser, the team performed an operation known as a spin-flip on two of the atoms, switching them to the state corresponding to 1.

Next, the team bombarded the array with a laser tuned to the state-0 atoms, to check that the information had genuinely been transferred to the register. The laser knocked the state-0 atoms off the carrier wave, leaving the state-1 atoms behind. Another picture from their CCD imaging system shows the state-1 atoms are exactly where they were at the beginning of the experiment.

The team is now working to create a quantum gate in which two or more qubits of the register will interact in a controlled way. Dominik Schrader, the lead scientist, he hopes to get there in two years. ®

Related stories

Computing needs a Grand Challenge
Supercool atoms and quantum computing
Japanese boffins advance quantum computing

Secure remote control for conventional and virtual desktops

More from The Register

next story
LOHAN packs bags for SPACEPORT AMERICA!
Spanish launch goes titsup, we're off to the US of A
Gigantic toothless 'DRAGONS' dominated Earth's early skies
Gummy pterosaurs outlived toothy competitors
'Leccy racer whacks petrols in Oz race
ELMOFO rakes in two wins in sanctioned race
Boffins ID freakish spine-smothered prehistoric critter: The CLAW gave it away
Bizarre-looking creature actually related to velvet worms
CRR-CRRRK, beep, beep: Mars space truck backs out of slippery sand trap
Curiosity finds new drilling target after course correction
Astronomers scramble for obs on new comet
Amateur gets fifth confirmed discovery
Boffins build CYBORG-MOTHRA but not for evil: For search & rescue
This tiny bio-bot will chew through your clothes then save your life
Vulture 2 takes a battering in 100km/h test run
Still in one piece, but we're going to need MORE POWER
What does a flashmob of 1,024 robots look like? Just like this
Sorry, Harvard, did you say kilobots or KILLER BOTS?
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 10 endpoint backup mistakes
Avoid the ten endpoint backup mistakes to ensure that your critical corporate data is protected and end user productivity is improved.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Rethinking backup and recovery in the modern data center
Combining intelligence, operational analytics, and automation to enable efficient, data-driven IT organizations using the HP ABR approach.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.