IBM Shows First Full Error Detection for Quantum Computers

Critical advances have been made by the IBM engineers to achieve Quantum Computing.

As per scientists the “Quantum Computers” will be equipped with the power of atoms and molecules to perform memory and processing tasks. Hence these computers will have the potential to perform certain calculations significantly faster than any present day silicon-based computer. It seems that present day computers may take several years to do some calculations which the Quantum computers can do in a matter of few seconds.

Scientists used to feel that a practical Quantum Computer is still some years away. Well to some extent it is true because the Quantum computer though super fast is extremely fragile and secondly even a small disturbance would lead to huge error. Hence the Quantum computers would need to detect as well as correct these errors before they can establish themselves as the super fast computers.

However, it seems that IBM scientists carried out an experiment of “quantum error detection code by using a square lattice of four super conducting qubits”. IBM scientist have thus created a new prototype design to overcome the error which they usually came across in quantum computing, as per a research that was published in Nature Communications on April 29th.

Further, IBM researchers have also said that the prototype can be developed into big computers. This surely is a very great achievement and can create a huge revolution in various industries including the military and defense systems. The quantum computing can also reach the auto industry for its safety. Well it will be useful in all those places which uses computers and technology because the quantum computers not only is capable of working with lightning speed but it can also store much more information as compared to the present computers.

Let us just check what this Quantum Computing is all about:

The regular computers use the ‘bits’ that represents the information as ‘0’ or ‘1’. Now the Quantum computers use the ‘quantum bits’ or ‘qubits’ which can represent the information as ‘0’, ‘1’ or both at the same time which can be written as ‘0+1’. Due to the qubits the Quantum computers are much faster than the regular computers.

The drawback with the qubits is that they sometimes flip, so sometimes they might just flip from ‘0’ to ‘1’ known as bit flip error which is also seen in the classical bits, or they can flip from ‘0+1’ to ‘0-1’ which is known as called a phase flip error. The phase flip error basically occurs because of the quantum physics phenomena which is also known as superposition wherein the qubits can also exist as as both ‘1’ and ‘0’ simultaneously and this error thus changes the superposition sign of the phase relationship between the ‘0’ and ‘1’ values. These flips occur without any warning and are the main cause of all the errors occurring in a quantum computer.

Usually the bit flip error is detected by the classical computer by copying the same bit many times and then the correct value is taken from the majority of the error free bits. On the other hand qubits try to directly copy them and this leads to the change in the quantum state which is the main reason for the fragility of the quantum.

Researchers handle this problem by using the quantum physics phenomena of entanglement wherein a qubit shares its quantum state with many other qubits via a quantum connection.

IBM’s system of 4 qubit grid demonstrates how scientists used this to get the information that was shared between the entangled adjacent qubits. Of the four, two qubits were the main “data” qubits while the other two were used as “measurement” qubits. Further, of the two qubits that were used for measurement, one detected the bit-flip errors in either neighboring data qubit and the other measured phase error in the data qubits.

As per the latest IBM study, scientists have found out the solution to detect both the flips that occur in the qubits, however it cannot “correct” the mistakes yet.

As per a research published in the journal Nature, in March 2015, the researchers from UCSB and Google carried out an experiment to first of all stabilize the qubits and secondly to program them in such a way so that they can find and fix the errors. For this purpose the Google et al used an pattern of nine linked qubits set in linear manner. The ultimate result of the experiment was that the linear nine linked qubits could not stop errors from happening however it could prevent the errors which usually messes up the later calculations. Thus Google team could not find a complete solution to the qubit flips.

Jerry Chow, Manager of Experimental Quantum Computing at IBM, told the Business Insider: “With our recent four-qubit network, we built a system that allows us to detect both types of quantum errors. The system comprises of a four-qubit lattice where two of the qubits act like sentries and monitor the other two qubits for errors. The lattice sits on top of a silicon chip that’s about one-quarter of an inch wide.”

Further by giving the reference of Google’s experiment with the array of nine linked qubits he also added: “IBM’s square-shaped prototype is the first demonstration of a system that has the ability to detect both bit-flip errors and phase errors at the same time. Detecting both types of flips is critical if we ever want working, error-free quantum computers.”

Chow also said: “IBM’s new design is also scalable. The only problem is working out how to manufacture silicon chips full of qubits on a mass scale.That’s going to require a lot more material science study.”

IBM researchers further added that once they figure out this problem of manufacturing the silicon chips of qubits on a mass scale they can easily use the same kind of error detection techniques on larger lattices and hence on a bigger computer.

Though quantum computing can revolutionize the Industries on a mass scale in future, for now Chow and his group are figuring out what all they can accomplish with the small quantum computers. It seems Chow and his group have already started experimenting using an eight qubit array.