Google shows Bristlecone quantum processor with 72 qubits

Google has presented a quantum processor with 72 qubits, which bears the name Bristlecone. According to the search giant, the processor should be used in research into reducing errors and scalability.

In addition, according to Google, the chip should be used in research into applications within simulations, optimization and machine learning. The company explains that the Bristlecone chip is based on the same principle as its linear array of nine qubits, but has been scaled up to a square array of 72 qubits. The processor would have low error rates in both readout and logic operations with gates of one and two qubits. The hope is that the low number of errors can be translated into the larger variant.

With the help of this processor, Google wants to demonstrate the principle of quantum supremacy, which means that a quantum chip outperforms a traditional supercomputer in solving a certain scientific problem. Google mentions that this requires that there are not too many errors. The company therefore says it has developed a benchmark that can provide an indication of the performance of a quantum processor.

While no one has yet reached the goal of quantum supremacy, Google expects that demonstration of this should be possible with a processor with at least 49 qubits. Ultimately, Bristlecone must be able to demonstrate that it is possible to build larger quantum computers.

Several companies are developing quantum chips. Intel recently developed a 49-qubit test chip called Tangle Lake. IBM said it had built a prototype processor with 50 qubits at the end of last year. In a quantum processor, the quantum state of particles is superimposed so that they can partly represent a 1 as well as a 0. Large speed gains can be achieved with a limited number of algorithms, such as when searching in huge databases and in cryptography.