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This is a coded message developed by RSA Laboratories, a company specializing in encryption, that can be cracked with a 1024 'bit' key that can factor the algorithm into prime number factors. There are, however, 21,024 possible variations of the key. A supercomputer and a network of 100,000 computers took 22 hours and 15 minutes to crack a similar but much smaller 56-bit algorithm at the RSA Data Security's DES Challenge III, a contest held in 1999 to test the algorithm's security. The larger algorithm has yet to be cracked.
Encryption and security are one of the many applications of quantum computing, a rapidly expanding field of research at the forefront of quantum mechanics. Physics Prof. Olivier Pfister is on his way to creating a quantum computer that will surpass classical computers in speed for specific tasks such as integer factoring.
An encryption algorithm like the one above traditionally takes several months to crack on a classical computer, Pfister said. The same decoding would take only a few minutes on a quantum computer, he added. Such algorithms are used all over the Internet, especially in the areas of banking and security.
Classical computers use 'bits' of information in the form of 0s and 1s, Pfister said. Quantum computers, on the other hand, use quantum bits, or qubits.
Many physical systems - from atoms to superconducting circuits and photons - can be used to implement qubits. Pfister chose light as the basis for his 'quantum system' for two reasons: It results in lower decoherence, or photon loss, and has larger scalability, or amount of qubits.
Though light is "hard to control because [photons] typically don't interact with anything, this very property also keeps decoherence at bay," he said.
Atoms are easier to manipulate than light, but this characteristic also gives them a disadvantage - the state of atoms changes randomly as they interact with energy and matter in their environment, from light to other atoms.
"You have to choose your poison," Pfister said.
If there is a light source that emits different frequencies, Pfister explained, then there are different harmonics, or specific frequencies, resonant at the same time.
"The fact is you can [create harmonic resonance] with light, with the electromagnetic field propagating [instead of the sound wave on the string as in music]," he said. "If you have an oscillating [light] wave and two mirrors at macroscopic distances [at each end] you easily have 20,000 wavelengths between the two mirrors."
Many wavelengths means many harmonics, which, if vibrating simultaneously, can yield femtosecond lasers which pulse at 10-15 seconds. As a comparison, lasers used in dermatology only pulse at 5-100 nanoseconds (10-9 ns).
"I'm trying to find where photons are when you have a million cavity modes," Pfister said, referring to the number of harmonic wavelengths in the physical space of the wave, for example the box of a microwave. "Each of these modes is a single frequency, a single quantum system; it can be used as a qubit."
The theoretical work of Glauber and the experimental work of Hall and H
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