New technique in error-prone quantum computing makes classical computers sweat

Phys.org  June 14, 2023 The widely accepted solution to noise in quantum computing is the implementation of fault-tolerant quantum circuits, which is out of reach for current processors. A team of researchers in the US (IBM -Yorktown Heights, NY, UC Berkeley) conducted experiments on a noisy 127-qubit processor and demonstrated the measurement of accurate expectation values for circuit volumes at a scale beyond brute-force classical computation. According to the researchers this represents evidence for the utility of quantum computing in a pre-fault-tolerant era. They established the accuracy of the measured expectation values by comparing them with the output of exactly […]

A Graphene Waveguide For Electrons

American physical Society  November 22, 2019 An electron carrying information in its quantum state and acting according to its wave nature can travel though a waveguide, but if multiple modes are available, then the electron can switch between them and lose information. An international team of researchers (USA – MIT, Japan, France) designed a device that includes a graphene flake sandwiched between two insulating sheets. On top of this structure sits a single carbon nanotube. A voltage applied across the CNT induces an electrostatic potential shaped like a rain gutter that extends down into the flake. The potential traps the […]