Open Doors For Robust Quantum Computation Without Errors Beckons

Youngkyu Sung, an MIT Graduate of electrical engineering and computer science in a news article revealed that tremendous progress is being made to allow computations get performed  with low error rates with superconducting quantum bits (qubits), errors in two-cubit gates, one of the building blocks of quantum computation, and noted that a way has been demonstrated to sharply reduce those errors.

This is coming after he and his team members who are all researchers from MIT made history by realizing a significant progress on the road toward the full realization of quantum computation without errors. They demonstrated a technique that expels common errors in the most essential operation of quantum algorithms, the two-qubits operation or “gate.”

A previous research had been carried out also by this same team, in synchronization with MIT Engineering Quantum systems. In Quantum algorithm in computers, the processing of information, a very delicate process is often times performed by the fragile qubits, which are highly susceptible to decoherence, due to the loss of their quantum mechanical behaviour. In cognizance of this, tunable couplers came into script, paving way for the researchers to turn two-qubit interactions on and off to control their operations while keeping the fragile qubits safe. This idea which birthed an important progress was cited, for usage by Google bringing about an important role in demonstration of the advantage that quantum computing supersedes classical computing.

In a case where the two-qubit gates were still viable to errors whilst the usage of a tunable couple was ongoing, unwanted interactions between the two qubits and between the qubits and the coupler were noticeable.

With noticeable unwanted interactions caused by the errors visible in the past but due to large number of qubits and gates, they obstructed the building of bigger quantum processors but right now, the errors are no more! Sung’s paper article review outlines ways to reducing errors using this new technique.

William D. Oliver,  Associate Professor of Electrical Engineering and Computer Science,  who doubles as the MIT Lincoln Laboratory fellow director of the Centre for Quantum Engineering, had opined:

“We have now taken the tunable coupler concept further and demonstrated near 99.9 percent fidelity for the two major types of two-qubit gates, known as Controlled-Z gates and iSWAP gates.

“Higher-fidelity gates increase the number of operations one can perform, and more operations translate to implementing more sophisticated algorithms at larger scales.”

Continuing, Oliver pointed out that “Qubit errors can be actively addressed by adding redundancy,” however, such a process only works if the gates are sufficiently good — above a certain fidelity threshold that depends on the error correction protocol.

“The most lenient thresholds today are around 99 percent. However, in practice, one seeks gate fidelities that are much higher than this threshold to live with reasonable levels of hardware redundancy.”

He concluded by stating that:

“The devices used in the research, made at MIT’s Lincoln Laboratory, were fundamental to achieving the demonstrated gains in fidelity in the two-qubit operations.”

 “Fabricating high-coherence devices is step one to implementing high-fidelity control.

According to his co-researcher, Sung: “High rates of error in two-qubit gates significantly limit the capability of quantum hardware to run quantum applications that are typically hard to solve with classical computers, such as quantum chemistry simulation and solving optimization problems.”

“In this sense, our new approach to reduce the two-qubit gate errors is timely in the field of quantum computation and helps address one of the most critical quantum hardware issues today,”

As at now, only smaller molecules have been tested upon on the quantum computers have also been easily tested on classical computers also.

“In this sense, our new approach to reduce the two-qubit gate errors is timely in the field of quantum computation and helps address one of the most critical quantum hardware issues today”, Sung concluded.