814 research outputs found
Ground State Spin Logic
Designing and optimizing cost functions and energy landscapes is a problem
encountered in many fields of science and engineering. These landscapes and
cost functions can be embedded and annealed in experimentally controllable spin
Hamiltonians. Using an approach based on group theory and symmetries, we
examine the embedding of Boolean logic gates into the ground state subspace of
such spin systems. We describe parameterized families of diagonal Hamiltonians
and symmetry operations which preserve the ground state subspace encoding the
truth tables of Boolean formulas. The ground state embeddings of adder circuits
are used to illustrate how gates are combined and simplified using symmetry.
Our work is relevant for experimental demonstrations of ground state embeddings
found in both classical optimization as well as adiabatic quantum optimization.Comment: 6 pages + 3 pages appendix, 7 figures, 1 tabl
Magnetic skyrmion logic gates: conversion, duplication and merging of skyrmions
Magnetic skyrmions, which are topological particle-like excitations in
ferromagnets, have attracted a lot of attention recently. Skyrmionics is an
attempt to use magnetic skyrmions as information carriers in next generation
spintronic devices. Proposals of manipulations and operations of skyrmions are
highly desired. Here, we show that the conversion, duplication and merging of
isolated skyrmions with different chirality and topology are possible all in
one system. We also demonstrate the conversion of a skyrmion into another form
of a skyrmion, i.e., a bimeron. We design spin logic gates such as the AND and
OR gates based on manipulations of skyrmions. These results provide important
guidelines for utilizing the topology of nanoscale spin textures as information
carriers in novel magnetic sensors and spin logic devices.Comment: 17 pages, 6 figure
All-spin logic operations: Memory device and Reconfigurable computing
Exploiting spin degree of freedom of electron a new proposal is given to
characterize spin-based logical operations using a quantum interferometer that
can be utilized as a programmable spin logic device (PSLD). The ON and OFF
states of both inputs and outputs are described by {\em spin} state only,
circumventing spin-to-charge conversion at every stage as often used in
conventional devices with the inclusion of extra hardware that can eventually
diminish the efficiency. All possible logic functions can be engineered from a
single device without redesigning the circuit which certainly offers the
opportunities of designing new generation spintronic devices. Moreover we also
discuss the utilization of the present model as a memory device and suitable
computing operations with proposed experimental setups.Comment: 6 pages, 7 figure
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