China’s Jiuzhang achieves Quantum Supremacy with light
Chinese researchers declared to have achieved quantum supremacy in the journal Science.
A system named Jiuzhang (ancient Chinese mathematical text) achieved Quantum supremacy with light. Quantum supremacy is the ability of a quantum computer to solve a problem that no classical computer can solve in a feasible amount of time.
In Oct 2019, Google had achieved Quantum Supremacy using the Programmable Superconducting Processor “Sycamore” It uses a superconducting material which is supercooled. Google’s 54-qubit processor is comprised of fast high-fidelity quantum logic gates. It performed a computation in 200 seconds, which would have taken worlds fastest supercomputer 10,000 years to produce the same output.
China’s Jiuzhang uses a different approach, which involves photons and a process called as boson sampling.
Subscribe to our newsletter for latest updates:
Boson sampling involves sampling from the probability distribution of identical bosons scatted in a linear interferometer. Although the problem is well defined for any bosonic particles, its photonic version is currently considered as the most promising platform for a scalable implementation of a boson sampling device, which makes it a non-universal approach to linear optical quantum computing.
The photonic quantum computer generates up to 76 output photon clicks, which yields an output state-space dimension of 1030 and a sampling rate that is ~1014 faster than using the state-of-the-art simulation strategy and supercomputers. The different variants of boson sampling include Scattershot boson sampling, Gaussian boson sampling, Classically simulable boson sampling tasks.
Jiuzhang can perform computation or a calculation in 200 seconds, which would take the fastest classical (non-quantum) supercomputer more than half a billion years to calculate.
In the experiment, up to 76 photons traversed a network of 100 channels. Chinese supercomputer Sunway TaihuLight, predicting the results that the quantum computer would get for anything beyond about 40 photons was intractable.
Google Sycamore is programmable, i.e. it can be programmed to execute different tasks. Jiuzhang can perform single task namely boson sampling.
Quantum computers fundamentally uses Quantum superposition. It says that like waves in classical physics, any two or more quantum states can be superimposed, and the result will be another valid quantum state. Also, every quantum state can be represented as a sum of two or more other distinct states.
Honeywell earlier this year announced that it had also built a quantum computer. Its quantum computer can perform a quantum volume of 64. With a variety of quantum computers being built, Quantum volume is a measurement developed by IBM, to measure how complex problems can be solved by a Quantum system. Quantum volume takes into consideration Number of qubits, Error rates & Connectivity of qubits.