Quantum computers will require complex software to manage errors
Highlighting another challenge to the development of quantum computers, theorists at the National Institute of Standards and Technology (NIST) have shown* that a type of software operation, proposed as a solution to fundamental problems with the computers’ hardware, will not function as some designers had hoped.
Quantum computers—if they can ever be realized—will employ effects associated with atomic physics to solve otherwise intractable problems. But the NIST team has proved that the software in question, widely studied due to its simplicity and robustness to noise, is insufficient for performing arbitrary computations. This means that any software the computers use will have to employ far more complex and resource-intensive solutions to ensure the devices function effectively.
Unlike a conventional computer’s binary on-off switches, the building blocks of quantum computers, known as quantum bits, or “qubits,” have the mind-bending ability to exist in both “on” and “off” states simultaneously due to the so-called “superposition” principle of quantum physics. Once harnessed, the superposition principle should allow quantum computers to extract patterns from the possible outputs of a huge number of computations without actually performing all of them. This ability to extract overall patterns makes the devices potentially valuable for tasks such as codebreaking.