897 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
Synthesis of Quantum Circuits for Linear Nearest Neighbor Architectures
While a couple of impressive quantum technologies have been proposed, they
have several intrinsic limitations which must be considered by circuit
designers to produce realizable circuits. Limited interaction distance between
gate qubits is one of the most common limitations. In this paper, we suggest
extensions of the existing synthesis flow aimed to realize circuits for quantum
architectures with linear nearest neighbor (LNN) interaction. To this end, a
template matching optimization, an exact synthesis approach, and two reordering
strategies are introduced. The proposed methods are combined as an integrated
synthesis flow. Experiments show that by using the suggested flow, quantum cost
can be improved by more than 50% on average.Comment: 14 pages, 11 figures, 3 table
Computing with spins: From classical to quantum computing
This article traces a brief history of the use of single electron spins to
compute. In classical computing schemes, a binary bit is represented by the
spin polarization of a single electron confined in a quantum dot. If a weak
magnetic field is present, the spin orientation becomes a binary variable which
can encode logic 0 and logic 1. Coherent superposition of these two
polarizations represent a qubit. By engineering the exchange interaction
between closely spaced spins in neighboring quantum dots, it is possible to
implement either classical or quantum logic gates.Comment: 3 figure
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
Minimization of Quantum Circuits using Quantum Operator Forms
In this paper we present a method for minimizing reversible quantum circuits
using the Quantum Operator Form (QOF); a new representation of quantum circuit
and of quantum-realized reversible circuits based on the CNOT, CV and
CV quantum gates. The proposed form is a quantum extension to the
well known Reed-Muller but unlike the Reed-Muller form, the QOF allows the
usage of different quantum gates. Therefore QOF permits minimization of quantum
circuits by using properties of different gates than only the multi-control
Toffoli gates. We introduce a set of minimization rules and a pseudo-algorithm
that can be used to design circuits with the CNOT, CV and CV quantum
gates. We show how the QOF can be used to minimize reversible quantum circuits
and how the rules allow to obtain exact realizations using the above mentioned
quantum gates.Comment: 11 pages, 14 figures, Proceedings of the ULSI Workshop 2012 (@ISMVL
2012
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