279 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
2D Qubit Placement of Quantum Circuits using LONGPATH
In order to achieve speedup over conventional classical computing for finding
solution of computationally hard problems, quantum computing was introduced.
Quantum algorithms can be simulated in a pseudo quantum environment, but
implementation involves realization of quantum circuits through physical
synthesis of quantum gates. This requires decomposition of complex quantum
gates into a cascade of simple one qubit and two qubit gates. The
methodological framework for physical synthesis imposes a constraint regarding
placement of operands (qubits) and operators. If physical qubits can be placed
on a grid, where each node of the grid represents a qubit then quantum gates
can only be operated on adjacent qubits, otherwise SWAP gates must be inserted
to convert non-Linear Nearest Neighbor architecture to Linear Nearest Neighbor
architecture. Insertion of SWAP gates should be made optimal to reduce
cumulative cost of physical implementation. A schedule layout generation is
required for placement and routing apriori to actual implementation. In this
paper, two algorithms are proposed to optimize the number of SWAP gates in any
arbitrary quantum circuit. The first algorithm is intended to start with
generation of an interaction graph followed by finding the longest path
starting from the node with maximum degree. The second algorithm optimizes the
number of SWAP gates between any pair of non-neighbouring qubits. Our proposed
approach has a significant reduction in number of SWAP gates in 1D and 2D NTC
architecture.Comment: Advanced Computing and Systems for Security, SpringerLink, Volume 1
Depth-Optimized Reversible Circuit Synthesis
In this paper, simultaneous reduction of circuit depth and synthesis cost of
reversible circuits in quantum technologies with limited interaction is
addressed. We developed a cycle-based synthesis algorithm which uses negative
controls and limited distance between gate lines. To improve circuit depth, a
new parallel structure is introduced in which before synthesis a set of
disjoint cycles are extracted from the input specification and distributed into
some subsets. The cycles of each subset are synthesized independently on
different sets of ancillae. Accordingly, each disjoint set can be synthesized
by different synthesis methods. Our analysis shows that the best worst-case
synthesis cost of reversible circuits in the linear nearest neighbor
architecture is improved by the proposed approach. Our experimental results
reveal the effectiveness of the proposed approach to reduce cost and circuit
depth for several benchmarks.Comment: 13 pages, 6 figures, 5 tables; Quantum Information Processing (QINP)
journal, 201
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