Tag Archives: Quantum Error Correction

Is Quantum Computing Harder than Expected?

Posted on by

This is a quite interesting article on Quantum Computing and how hard it really is.

It is well known that Quantum Computers are prone to Quantum Errors, and this issue grows with the number of Qubits. The typical estimate is that an useful Quantum Computer would need approx. 1.000 physical Qubits to correct the Quantum Errors of a single “logical” Qubit. Even if there are advancements in this topic (see for example this post), this is still a problem to be solved in practice.

Another potential issue is that Quantum Computers have been proposed to efficiently solve many problems including optimization, fluid dynamics etc. besides those problems for which a Quantum Computer would provide exponential speed-up, such as factoring large numbers and simulating quantum systems. But if a Quantum Computer does not provide an exponential speed-up in solving a problem, there is the possibility that actually it would be slower than a current “classical” computer.

But the big question remains: will a real useful Quantum Computer arrive soon? If yes, how soon?

“Error Suppression” for Quantum Computers

Posted on by

Recently IBM announced that it has integrated in its Quantum Computers an “Error Suppression” technology from Q-CTRL which can reduce even by orders of magnitude the likelihood of quantum errors when running an algorithm on a Quantum Computer (see for example here).

Quantum errors are inherent to Quantum Computing, and the likelihood of error usually grows with the number of qubits. Theoretical Quantum Error Correction Codes exist, but their practical implementation is not easy; for example, the simplest codes can require even a thousand error correction qubits for each computation qubit.

The approach by Q-CTRL seems to adopt a mixture of techniques to identify the more efficient and less quantum error-prone way of running a computation, for example by optimizing the distribution of quantum logical gates on the qubits and by monitoring quantum errors to design more efficient quantum circuits.

Surely it is an interesting approach, we’ll see how effective it will really turn out to be in reducing the likelihood of quantum errors.