Abstract: A passively protected quantum memory in two dimensions includes: a square lattice of harmonic oscillators; each of the harmonic oscillators experiencing a coherent two-photon drive process and an incoherent two-photon loss process; each of the harmonic oscillators coupled to its nearest neighbor harmonic oscillator via a ferromagnetic Ising parity-parity interaction, which can be realized, for example, by coupling LC oscillators with a Josephson junction; and a cold bath coupled to the harmonic oscillators at a temperature such that parities of neighboring harmonic oscillators align through an energy dissipation process.

Abstract: A gravure printing system is provided. The gravure printing system includes a plate cylinder, an ink source, a cover blade, and a doctor blade. The plate cylinder has a circumferential surface with at least one groove. The ink source is adapted to provider an ink onto the circumferential surface of the plate cylinder. The cover blade is adapted to form an anti-drying layer on the plate cylinder from the ink. The doctor blade is adapted to contact the plate cylinder and fill the at least one groove with the ink. A point on the circumferential surface sequentially passes by the ink source, the cover blade, and the doctor blade as the plate cylinder rotates. A Young's modulus of a material of the cover blade is less than a Young's modulus of a material of the doctor blade. A method of using the gravure printing system is also provided.