127 research outputs found
Synthesis and Optimization of Reversible Circuits - A Survey
Reversible logic circuits have been historically motivated by theoretical
research in low-power electronics as well as practical improvement of
bit-manipulation transforms in cryptography and computer graphics. Recently,
reversible circuits have attracted interest as components of quantum
algorithms, as well as in photonic and nano-computing technologies where some
switching devices offer no signal gain. Research in generating reversible logic
distinguishes between circuit synthesis, post-synthesis optimization, and
technology mapping. In this survey, we review algorithmic paradigms ---
search-based, cycle-based, transformation-based, and BDD-based --- as well as
specific algorithms for reversible synthesis, both exact and heuristic. We
conclude the survey by outlining key open challenges in synthesis of reversible
and quantum logic, as well as most common misconceptions.Comment: 34 pages, 15 figures, 2 table
Fault-Tolerant Logical Gate Networks for CSS Codes
Fault-tolerant logical operations for qubits encoded by CSS codes are
discussed, with emphasis on methods that apply to codes of high rate, encoding
k qubits per block with k>1. It is shown that the logical qubits within a given
block can be prepared by a single recovery operation in any state whose
stabilizer generator separates into X and Z parts. Optimized methods to move
logical qubits around and to achieve controlled-not and Toffoli gates are
discussed. It is found that the number of time-steps required to complete a
fault-tolerant quantum computation is the same when k>1 as when k=1.Comment: 13 pages, 16 figures. The material in the appendix was included in a
previous quant-ph eprint, but not yet published; it has been corrected and
clarified. The rest is new. Replacement version: various small corrections
and clarification
Approximate Quantum Adders with Genetic Algorithms: An IBM Quantum Experience
It has been proven that quantum adders are forbidden by the laws of quantum
mechanics. We analyze theoretical proposals for the implementation of
approximate quantum adders and optimize them by means of genetic algorithms,
improving previous protocols in terms of efficiency and fidelity. Furthermore,
we experimentally realize a suitable approximate quantum adder with the cloud
quantum computing facilities provided by IBM Quantum Experience. The
development of approximate quantum adders enhances the toolbox of quantum
information protocols, paving the way for novel applications in quantum
technologies
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