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Showing posts with label QuantumComputing. Show all posts
Showing posts with label QuantumComputing. Show all posts

Wednesday, June 21, 2023

IBM Claims Major Breakthrough in Quantum Computing Reliability

Claims have been many.

IBM Claims Major Breakthrough in Quantum Computing Reliability  in Extremetech

Quantum computers are fast, but they produce a lot of wrong answers. IBM says its error mitigation technique could fix that.

By Ryan Whitwam,  June 15, 2023

Today's most powerful supercomputers can simulate complex weather patterns and the birth of stars, but even a modest quantum computer could outperform those machines. The mysterious nature of quantum mechanics has thus far made quantum computing little more than a curiosity, but IBM is claiming a significant breakthrough. According to IBM's Jay Gambetta, we've reached "the era of utility."

Quantum computers are a hot topic for research, but they haven't been useful for doing calculations yet. We keep trying because of the incredible potential of quantum computing, which takes advantage of weird quantum properties like entanglement, interference, and superposition to accelerate calculations. For example, the digital computers we've used for decades use transistors to signify a 1 or a 0. Using superposition, a quantum bit (qubit) can be a 1, 0, or both. Holding multiple values allows a qubit to perform multiple calculations, whereas a classical computer must do them individually.

These systems are incredibly fast, true, but they don't produce consistent results—at least until now, claims the study published in Nature. Google claimed quantum supremacy in 2019, producing calculations it says would have taken thousands of years on a digital computer. However, a follow-up analysis has shown that a conventional computer can do the same tabulations if given a little more time. IBM's claim is not about speed as much as it's about reliability. For a quantum computer to be useful, it needs to give the same answer every time, and IBM took a big step in that direction with a demonstration of error mitigation.

The team created a simulation of 127-atom bar magnets with a 127-qubit computer, a system known as an Ising model that is often used to study magnetism. At that scale, the magnets are affected by quantum factors, making it impossible to simulate on a classical computer accurately. The researchers leveraged quantum interference to nudge the results, pushing them farther from the solution. By introducing noise into the calculations, the IBM Quantum team could understand the effects of noise in the simulation, working backward to reach the ideal, low-noise result ....'

Thursday, April 14, 2022

Quantum Computers Get Smarter at Simulating Chemistry

Useful direction, having worked in a chem lab, would be useful to have an idea of what you will get. 

Quantum Computers Get Smarter at Simulating Chemistry

IEEE Spectrum, Charles Q. Choi, March 17, 2022

A team of scientists from multiple institutions used Google's Sycamore quantum processor to conduct the largest chemistry simulations involving quantum computers to date, tapping a new method that may better handle quantum circuits' noise. The researchers ran a fermionic quantum Monte Carlo algorithm in a hybrid classical-quantum computation framework so it would scale well. They employed 16 quantum bits (qubits) on the 53-qubit Sycamore system to calculate the ground state of H4 molecules, molecular nitrogen, and solid diamond molecules. Google Quantum AI's William Huggins said the hybrid approach can produce very precise ground-state estimates with more noise than the previous holder of the record for chemical simulations with quantum computing, the variational quantum eigensolver (VQE) algorithm, can tolerate.  ... '