We study variants of Shor's code that are adept at handling single-axis correlated idling errors, which are commonly observed in many quantum systems. By using the repetition code structure of the Shor's code basis states, we calculate the logical channel applied to the encoded information when subjected to coherent and correlated single qubit idling errors, followed by stabilizer measurement. Changing the signs of the stabilizer generators allows us to change how the coherent errors interfere, leading to a quantum error correcting code which performs as well as a classical repetition code of equivalent distance against these errors. We demonstrate a factor of 4 improvement of the logical memory in a distance-3 logical qubit implemented on a trapped-ion quantum computer. Even-distance versions of our Shor code variants are decoherence-free subspaces and fully robust to identical and independent coherent idling noise.
\"This book proposes a new theory of Senate agenda setting that reconciles a divide in literature between the conventional wisdom - in which party power is thought to be mostly, if not completely, undermined by Senate procedures and norms - and the apparent partisan bias in Senate decisions noted in recent empirical studies. Chris Den Hartog and Nathan W, Monroe's theory revolves around a \"costly consideration\" framework for thinking about agenda setting, where moving proposals forward through the legislative process is seen as requiring scarce resources. To establish that the majority party pays lower agenda consideration costs through various procedural advantages, the book features a number of chapters examining partisan influence at several stages of the legislative process, including committee reports, filibusters and cloture, floor scheduling, and floor amendments. Not only do the results strongly support the book's theoretical assumption and key hypotheses, but they shed new light on virtually every major step in the Senate's legislative process\"--Provided by publisher.
A collection of trapped atomic ions represents one of the most attractive platforms for the quantum simulation of interacting spin networks and quantum magnetism. Spin-dependent optical dipole forces applied to an ion crystal create long-range effective spin-spin interactions and allow the simulation of spin Hamiltonians that possess nontrivial phases and dynamics. Here we show how appropriate design of laser fields can provide for arbitrary multidimensional spin-spin interaction graphs even for the case of a linear spatial array of ions. This scheme uses currently existing trap technology and is scalable to levels where classical methods of simulation are intractable.
The best protection against this wear is to hard surface with carbide or chrome-carbide filler metals. * For a more severe type of abrasion, high-stress grinding -a type of wear that occurs from repeated grinding and crushing - filler metals that contain austenitic manganese, martensitic irons or titanium carbides are best. * Finally, to protect against gouging abrasion, the most severe type caused by large rocks pressing and creating grooves on the material, use a filler metal with high carbide alloys and austenitic manganese as protection. An austenitic manganese steel filler metal is a good choice in this situation, as it offers reliable work-hardening characteristics to protect against compressive loads and high mechanical stress.
Hard surfacing is a specialized welding process that deposits an alloy on a metallic part to return worn areas to their original dimensions and/or protect new metal parts against wear. The process provides equipment with significant abrasion and impact resistance; it can also reduce downtime for replacing broken or worn parts.