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Electroless-depositing a metal from solution to a substrate and patterning it using microcontact printing is an alternative to the conventional patterning of vacuum-deposited metals using photolithography. Here, we pattern Cu onto 15 × 15 sq-inch glass substrates by (i) self-assembly of a thin layer of amino-derivatized silanes to the glass, (ii) binding Pd/Sn catalytic particles to the silanes, (iii) electroless deposition of ∼120 nm of Cu on the catalytic surface, (iv) microcontact printing hexadecanethiol on the Cu film using an accurate printing tool, and (v) selectively etching the printed Cu using hexadecanethiol as a resist. This method is particularly attractive for the fabrication of metallic gates for thin-film transistor liquid-crystal displays.

Quantum computing relies on the operation of qubits in an environment as free of noise as possible. Assessing the quality of this environment is a key aspect of ensuring high-fidelity implementations based on superconducting qubits. Relaxation, decoherence, dephasing, and quasiparticle tunneling rates have been measured for various shielding configurations used in the measurement environment for state-of-the-art transmon qubits. An ensemble of approximately 120 control devices was used for this study, with five different capacitor pad designs. The shielding elements varied in the configuration included an indium gasket at the qubit can's lid, Cryoperm magnetic shielding, the mixing chamber shield of the dilution refrigerator, the inclusion of a vacuum pump-out port, and capping unused subminiature version A connectors at the top of the measurement can's lid. It was found that the qubit lifetimes T1, T2, and Tϕ are robust to the all of configuration changes tried until the mixing chamber shield was removed, significantly increasing blackbody radiation levels in the qubit measurement space, where in that limit it was found that tapering the qubit pads reduced the amount of loss. In contrast, the quasiparticle tunneling rates were found to be extremely sensitive to all configuration changes tested. Consistent with earlier reports [McEwen et al., arXiv:2104.05219 (2021); Cardani et al., Nat. Commun. 12, 2733 (2021); Wilen et al., Nature 594, 369–373 (2021); Ristè et al. Nat. Commun. 4, 1913 (2013)], the findings from this study indicate that non-equilibrium quasiparticles do not currently limit the lifetimes of well-shielded transmon qubits.

As 1999 ended, IBM announced its intention to construct a onepetaflop supercomputer. The construction of this system was based on a cellular architecture-the use of relatively small but powerful building blocks used together in sufficient quantities to construct large systems. The first step on the road to a petaflop machine (one quadrillion floating-point operations in a second) is the Blue Genet/L supercomputer. Blue Gene/L combines a low-power processor with a highly parallel architecture to achieve unparalleled computing performance per unit volume. Implementing the Blue Gene/L packaging involved trading off considerations of cost, power, cooling, signaling, electromagnetic radiation, mechanics, component selection, cabling, reliability, service strategy, risk, and schedule. This paper describes how 1,024 dual-processor compute application-specific integrated circuits (ASICs) are packaged in a scalable rack, and how racks are combined and augmented with host computers and remote storage. The Blue Gene/L interconnect, power, cooling, and control systems are described individually and as part of the synergistic whole.