12-Spin-Qubit Arrays Fabricated on a 300 mm Semiconductor Manufacturing Line.

Intel's efforts to build a practical quantum computer are focused on developing a scalable spin-qubit platform leveraging industrial high-volume semiconductor manufacturing expertise and 300 mm fabrication infrastructure. Here, we provide an overview of the design, fabrication, and demonstration of a new customized quantum test chip, which contains 12-quantum-dot spin-qubit linear arrays, code named Tunnel Falls. These devices are fabricated using immersion and extreme ultraviolet lithography (EUV), along with other standard high-volume manufacturing (HVM) processes as well as production-level process control.

Probing single electrons across 300-mm spin qubit wafers.

Building a fault-tolerant quantum computer will require vast numbers of physical qubits. For qubit technologies based on solid-state electronic devices, integrating millions of qubits in a single processor will require device fabrication to reach a scale comparable to that of the modern complementary metal-oxide-semiconductor (CMOS) industry. Equally important, the scale of cryogenic device testing must keep pace to enable efficient device screening and to improve statistical metrics such as qubit yield and voltage variation.

Effect of Quantum Hall Edge Strips on Valley Splitting in Silicon Quantum Wells.

We determine the energy splitting of the conduction-band valleys in two-dimensional electrons confined to low-disorder Si quantum wells. We probe the valley splitting dependence on both perpendicular magnetic field B and Hall density by performing activation energy measurements in the quantum Hall regime over a large range of filling factors. The mobility gap of the valley-split levels increases linearly with B and is strikingly independent of Hall density.

A crossbar network for silicon quantum dot qubits.

The spin states of single electrons in gate-defined quantum dots satisfy crucial requirements for a practical quantum computer. These include extremely long coherence times, high-fidelity quantum operation, and the ability to shuttle electrons as a mechanism for on-chip flying qubits. To increase the number of qubits to the thousands or millions of qubits needed for practical quantum information, we present an architecture based on shared control and a scalable number of lines.

Rate constants of nine C6-C9 alkanes with OH from 230 to 379 K: chemical tracers for [OH].

We report absolute rate-constant measurements for the reactions of nine C(6)-C(9) alkanes with OH in 8-10 torr of nitrogen from 230 to 379 K in the Harvard University High-Pressure Flow System. Hydroxyl concentrations were measured using laser-induced fluorescence, and alkane concentrations were measured using Fourier transform infrared Spectroscopy. Ethane's reactivity was simultaneously measured as a test of experimental performance.

Mechanism of HO Formation in the Gas-Phase Ozone-Alkene Reaction. 1. Direct, Pressure-Dependent Measurements of Prompt OH Yields.

The gas-phase reaction of ozone with alkenes is known to be a dark source of HO radicals (such as OH, H, and R) in the troposphere, though the reaction mechanism is currently under debate. It is understood that a key intermediate in the reaction is the carbonyl oxide, which is formed with an excess of vibrational energy. The branching ratios of the ozone-alkene reaction products (and thus HO yields) depend critically on the fate of this intermediate:  it may undergo unimolecular reaction (forming either OH or dioxirane) or be collisionally stabilized by the bath gas.

Diagnosis of obstructive jaundice.

The diagnosis of obstructive jaundice remains difficult yet vital, since operative decompression may relieve extrahepatic blockage, but operation can only harm patients with intrahepatic block or parenchymal cell inflammation or necrosis. Three new diagnostic methods (liver scanning, angiography, and transjugular transhepatic cholangiography) are reviewed, as is bilirubin metabolism, so important in the diagnosis of jaundice. Three clinical problems are discussed: extrahepatic obstruction due to cancer of the pancreas, biliary atresia causing jaundice in the newborn, and the diffuse ductal obstruction known as sclerosing cholangitis.