Quantum Algorithms

Wednesday, November 24, 2004

Quantum chip circuitry demonstrated

EE Times - Quantum chip circuitry demonstrated: "

*Yale University researchers have demonstrated how to build a quantum computer operating on quantum bits, or qubits, which hold a superposition of quantum states.*[...]

*The advantages of Yale's method include the relatively small size of its qubit repositories - about a square micron - and the ability to read a qubit's state without disturbing it - the bane of quantum computers to date.*[...]

*The Yale approach stored qubits in a Cooper-box with over 1 billion superconducting aluminum atoms acting together, thereby providing a kind of quantum momentum that allowed a 'probing' photon to read out a qubit's state from the Cooper-box without changing its state.*"

**Updates:**I found this pdf to be a pretty good lightly-technical explanation of the experiment. Also, here [zhurnal.net] and here [www.lkb.ens.fr] are some interesting explanations of Quantum Non-Demolition.

The NSA Wants Your Quantum Algorithms

NSA Funding Opportunity in Quantum Computing Algorithms: "

*The National Security Agency solicits proposals for one-year research grants in the area of Quantum Computing Algorithms. [...] We are not interested in funding work such as quantum error correction, which supports the 'infrastructure' of quantum computation but is not a quantum algorithm in our sense. We are more interested in algorithms related to number theory, algebra, and combinatorics than in topics such as physical modeling and database analysis.*"

Sunday, November 14, 2004

Single Field Qubit Control

Single field shapes quantum bits TRN 110304:

*"Researchers have recently realized that it may be possible to control the electrons in a quantum computer using a single magnetic field rather than having to produce extremely small, precisely focused magnetic fields for each electron"*

Grover's Sampling Algorithm

Quantum Sampling Algorithm TRN 062800:

*"The sampling algorithm, written by Bell Labs' researcher Lov K. Grover, enables three types of applications for quantum computing: statistical sampling, searching with sketchy information and Monte Carlo integration [...] Although the sampling algorithm is probably not as 'novel and exciting' as Grover's original search algorithm, no one doubts the importance of sampling on quantum computers"*

**Update**

*:*Sorry for not noticing sooner, but this story is fairly old (July 2000) which I should have at least mentioned.

Saturday, November 06, 2004

Particle Physics for the Rest of Us

Symmetry Magazine has recently debuted, which is a joint venture of SLAC and Fermi Lab. The editor, David Harris, also has a blog.

Tuesday, November 02, 2004

August Wrap Up

-2 million correlated entangled photon pairs produced per second

-Entangled quantum dots

-New way to synthesize quantum dots (and more here)

-Photon teleportation over 600m

-Controlled emission rates of quantum dots

-Five photons entangled

-Open destination quantum teleportation