Being Clever About Correcting Qubit Errors

Scientists one step closer to a fully functioning quantum computer

Selected notes ~

+  Just like ordinary computers, however, quantum computers need a way to transfer information between qubits, and this presents a major experimental challenge.

+  “A quantum computer needs to have many qubits, and they’re really difficult to make and operate,” Nichol says. “The state-of-the art right now is doing something with only a few qubits, so we’re still a long ways away from realizing the full potential of quantum computers.”

All computers, including both regular and quantum computers and devices like smart phones, also have to perform error correction. A regular computer contains copies of bits so if one of the bits goes bad, “the rest are just going to take a majority vote” and fix the error. However, quantum bits cannot be copied, Nichol says, “so you have to be very clever about how you correct for errors. What we’re doing here is one step in that direction.”

+  Quantum error correction requires that individual qubits interact with many other qubits. This can be difficult because an individual electron is like a bar magnet with a north pole and a south pole that can point either up or down. The direction of the pole — whether the north pole is pointing up or down, for instance — is known as the electron’s magnetic moment or quantum state.

+  Nichol and his colleagues cooled down a semiconductor chip to extremely low temperatures. Using quantum dots — nanoscale semiconductors — they trapped four electrons in a row, then moved the electrons so they came in contact and their states switched.

+  “There’s an easy way to switch the state between two neighboring electrons, but doing it over long distances — in our case, it’s four electrons — requires a lot of control and technical skill,” Nichol says. “Our research shows this is now a viable approach to send information over long distances.”

Source:  Science Daily.  University of Rochester,  Scientists one step closer to a fully functioning quantum computer…

Content may have been edited for style and clarity.