Researchers achieve quantum entanglement of three electrons

The quantum entanglement of three electrons, using an ultrafast optical pulse and a quantum well of a magnetic semiconductor material, has been demonstrated in a laboratory at the University of Michigan, marking another step toward the realization of a practical quantum computer. While several experiments in recent years have succeeded in entangling pairs of particles, few researchers have managed to correlate three or more particles in a predictable fashion.

Heisenberg’s revenge: Energy need may cap size, ability of quantum computers

The energy required to create an accurate quantum computer may limit the ability of scientists to make these novel devices small, fast, cheap and efficient, says a University of Arkansas researcher. Quantum computing relies on using single atomic particles as units for information storage. Manipulating this information requires pulsed electromagnetic fields?which contain energy. The researcher found that the energy needed to perform a calculation is inversely proportional to the error rate: In other words, more energy means less uncertainty.

Researchers claim advance in quantum cryptography

Researchers have demonstrated a new high-speed quantum cryptography method that uses the properties of light to encrypt information into a form of code that can only be cracked by violating the physical laws of nature. The method promises security even against information security’s greatest foe: the not-yet-invented but still-feared powerful quantum computer, which could break almost any conventional code. The researchers transmitted encrypted data at the rate of 250 megabits per second. Because it uses standard lasers, detectors and other existing optical technology to transmit large bundles of photons, the protocol is more than 1,000 times faster than its main competitor, a technique based on single photons that is difficult and expensive to implement, the researchers say.