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Published On: Nov 25, 2005 03:07 AM
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Cool, but what's the Frames Per Second?
Because each qubit carries two
values, a quantum computer with two qubits could carry out four parallel
calculations, one with three qubits eight calculations, and so on. "I see no
major technical obstacles to the system I envisage working with 100 qubits,"
says Yao.
As many of you who know me will recognize, the
FPS (Frames Per Second) reference has to do with video gaming and system
performance. Every time a new
supercomputer comes out the very first thought that pops into my head is: "I
wonder what the frame rate on Doom 3 is gonna be on that thing!" -That's
usually followed by an urge to work at one of those places just so I could sneak
in with my install CD and spend the night shift in gamers
heaven.Why the rest of the world
hasn't reacted in the same fashion is still beyond my
grasp.Anyway - That question popped
back in my head in MAJOR fashion this evening! I can't wait to have my own
Quantum Bubble based Playstation!(BTW:
I'm still working on the ultimate over-clockers cooling hardware: a USB based
adiabatic demagnetization refrigerator. I
figure $19.99 each.)Check out this
story:New Scientist
Quantum bubbles are the
keyAs futuristic as quantum
computers seem, what with all those qubits and entangled atoms, here is an idea
that promises to make atom-based quantum computers look passé even before
anyone has built a full-sized version.It
seems that bubbles of electrons lined up in ultracold liquid helium could be
used to build a quantum computer capable of carrying out a staggering 1030
simultaneous calculations.To carry out
these simultaneous calculations, quantum computers normally exploit entities
such as atoms and molecules, which can be in several quantum states at once, to
encode bits in those quantum states – the famous qubits. But Weijun Yao of
Brown University in Providence, Rhode Island, wants to replace atoms with
curious things called electron
bubbles.To make an electron bubble,
start with liquid helium that has been cooled below 2.17 kelvin so that it
behaves like a superfluid, a state of matter with zero viscosity. Now inject a
fast-moving electron into the superfluid. When the electron eventually slows to
a halt after numerous collisions with helium atoms, it creates a cavity about
3.8 nanometres across by repelling nearly 700 atoms' worth of helium around it
(New Scientist, 14 October 2000, p
24).It is this cavity that makes the
electron bubble so very valuable. In a quantum computer, the quantum entities
need to be isolated from their surroundings to preserve their fragile states.
"What could be more isolated than an electron in a bubble?" asks Yao. "The
electron inside each bubble interacts very weakly with the background helium
atoms."Yao says 0s or 1s could be
encoded in the electrons' spins. In the presence of a magnetic field, the spin
can either be parallel or anti-parallel to the field. Crucially, an electron's
spin can exist in both states at the same time, enabling the qubit to be both 0
and 1.According to Yao, large numbers of
electrons, each in its own bubble, can be neatly caged using a combination of a
device called a linear quadrupole trap, which traps the electrons in a line, and
a set of conducting rings, which create a voltage "valley" for each bubble (see
Diagram).All the spins can be
initialised to the same value by cooling the apparatus to 0.1 kelvin. You can
then manipulate the electrons by applying a combination of a magnetic field
gradient along the line and varying the frequency of the voltages in the
quadrupole trap. This changes the spin of individual electrons and makes them
interact to perform logicgate operations (www.arxiv.org/ cond-mat/0510757). To
read the spin of an electron, the voltage at the end of the electron chain can
be lowered so that each bubble drifts in the magnetic field gradient at a
velocity that depends on the electron's spin. This drift velocity can be read
using lasers.Because each qubit carries
two values, a quantum computer with two qubits could carry out four parallel
calculations, one with three qubits eight calculations, and so on. "I see no
major technical obstacles to the system I envisage working with 100 qubits,"
says Yao. "That means it could do 1000 billion billion billion operations all at
once."
###
Written by Marcus
ChownIF REPORTING ON THIS STORY, PLEASE
MENTION NEW SCIENTIST AS THE SOURCE AND, IF PUBLISHING ONLINE, PLEASE CARRY A
HYPERLINK TO: http://www.newscientist.com"This
article is posted on this site to give advance access to other authorised media
who may wish to quote extracts as part of fair dealing with this copyrighted
material. Full attribution is required, and if publishing online a link to www.newscientist.com is also
required. The story below is the EXACT text used in New Scientist, therefore
advance permission is required before any and every reproduction of each article
in full. Please contact celia.thomas@rbi.co.uk. Please
note that all material is copyright of Reed Business Information Limited and we
reserve the right to take such action as we consider appropriate to protect such
copyright."THIS ARTICLE APPEARS IN NEW
SCIENTIST MAGAZINE ISSUE: 26 NOVEMBER 2005
Posted: Thu - November 24, 2005 at 12:30 AM
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