Approaching Decoherence-Free QubitsCategory: Science & Technology
Posted: September 24, 2013 08:47AM
A problem for any kind of information storage technology is corruption of the information. This problem manifests itself in different ways with different technologies, and perhaps the most extreme is decoherence, which quantum computers can suffer from. Fortunately researchers at Berkeley Lab and China's Tsinghua University have made a discovery that could make decoherence of qubits impossible.
Qubits, or quantum bits, store information in quantum mechanical states that are impossible according to classical mechanics. Decoherence is when the quantum mechanical state is lost, and the qubit acts like a classical particle, losing whatever information it previously stored. One way to prevent decoherence is to use a quasiparticle called a 'Majorana zero mode' as the qubit. These quasiparticles have never been observed though, but have been predicted in topological insulators with superconducting surfaces. Topological insulators have conductive (or superconductive) surfaces, but an insulating volume, and some interesting physics at the interface.
What the researchers have done is fabricate such a topological insulator that preserves it superconductivity at a higher temperature and has a larger energy gap for electrons to travel through than others before it. This makes it a prime candidate for detecting Majorana zero modes, and once they are found more work can be done to fully utilize them in future quantum computers.
Source: Berkeley Lab