Quantum supremacy (sycamore processor)

29 December 2021

Introduction:

A powerful machine is called a supercomputer via its speed and memory. Generally, quantum computers work based on small modules like atoms and molecules. In 2019, Google claimed that they have achieved quantum supremacy with the help of a newly designed sycamore processor.

The processor is about 54 qubits (quantum bits). Qubits can hold up to 2 bits of data, that’s why researchers are using the qubits for encoding. In qubits, the processor can have 0 and 1 simultaneously. If any complex algorithm is provided then this processor is taking the time of 200 seconds while other supercomputers can perform this amount of work in nearly 10,000 years.

It’s Goal:

The goal, as with Google’s quantum supremacy experiment, was to perform a random computation involving 54 qubits that computer scientists could be as confident as possible that would actually take steps of 9 quadrillions to make the conventional computer. The qubits in the click are laid out in a roughly rectangular grid, with each qubit capable of interacting with its neighbors. Control signals, sent by wire from classical computers outside the dilution refrigerators, tell each orbit how to behave, including when and when to interact with their neighbors.

Operations:

To find out how it works, imagine quantum computing amateurs who come to the lab to run quantum algorithms on their new processors. They can build the algorithms from a dictionary of primary gate operations. Since each gate has the potential for error, the guests will want to limit the model to a high sequence with about a thousand gates. Assume that the programmers have zero experience, first look like a random sequence of gates, which one might think of as a “hello” program for a quantum computer. Since random gates have no structure that simple algorithms can perform, it usually takes a significant amount of normal supercomputer effort to trigger such quantum gates.

In depth:

The experiment was run on a high program 54-qubit processor called ‘sycamore’. It consists of a 2d grid, and each qubit is connected to 4 other qubits. As a result, the chip has a sufficient connection that qubit can easily interact throughout the processor, making it impossible to efficiently simulate qubit states with a classical computer. The success of the experiment was conducted by increased parallelism due to the advanced 2 qubit gates, which reliably achieve high record performance even when multiple gates are operated concurrently. Thus, achieved this performance by using a new type of control knob capable of turning off the connection between neighboring qubits.

Conclusion:

This processor is made on superconducting qubits that can now work efficiently in vector space with dimensions of 9e+15, which is beyond the reach of the other fastest classical supercomputers that are present now. This experiment marks define the computation that can only be performed on a qubit processor. Hence this processor has attained the regime of quantum supremacy. In the future, we do expect that the computational power will continue to grow at a double rate as the cost of simulating quantum circuits grows gradually with system volume and hardware.