Steady cat state generation for nuclear spins thro

Steady cat state generation for nuclear spins through electric quadrupole interaction

Ceyhun Bulutay
Comments: 8 pages, 6 figures
Subjects: Quantum Physics (quant-ph); Other Condensed Matter (cond-mat.other)

Cat codes are one of the promising encoding schemes for quantum information that enables hardware-efficient error correction. So far, only photonic cat states produced by superconducting circuits have been under consideration. Their realization within coherent spin states (CSS) can pave the way toward nuclear magnetic resonance-based implementations of this new class of codes. Here, we show how the crucial superpositions of CSS can be generated for the nuclear spins. This is through the intrinsic electric quadrupole interaction involving a critical role by the biaxiality term that is readily available, as in strained heterostructures of semiconductors, or defect centers having nearby quadrupolar spins. The persistence of the cat states is achieved using a rotation pulse so as to harness the underlying fixed points of the classical Hamiltonian. We classify the two distinct types as polar- and equator-bound over the Bloch sphere with respect to principal axes, both of which are, so-called mod~2 cat states. Their optimal performance as well as sensitivity under numerous parameter deviations are analyzed. Finally, we show that a higher level, mod 4 cat state, with one of the legs rotating can also be produced along the same spirit using three pulses

https://arxiv.org/abs/1610.07046

inverted tetrapod third level spin state...you know the one above that one! Slightly Stoked~