Marek A. Perkowski

Optimal synthesis of multiple output Boolean functions using a set of quantum gates by symbolic reachability analysis

This paper proposes an approach to optimally synthesize quantum circuits by symbolic reachability analysis, where the primary inputs and outputs are basis binary and the internal signals can be nonbinary in a multiple-valued domain. The authors present an optimal synthesis method to minimize quantum cost and some speedup methods with nonoptimal quantum cost. The methods here are applicable to small reversible functions. Unlike previous works that use permutative reversible gates, a lower level library that includes nonpermutative quantum gates is used here. The proposed approach obtains the minimum cost quantum circuits for Miller gate, half adder, and full adder, which are better than previous results. This cost is minimum for any circuit using the set of quantum gates in this paper, where the control qubit of 2-qubit gates is always basis binary. In addition, the minimum quantum cost in the same manner for Fredkin, Peres, and Toffoli gates is proven. The method can also find the best conversion from an irreversible function to a reversible circuit as a byproduct of the generality of its formulation, thus synthesizing in principle arbitrary multi-output Boolean functions with quantum gate library. This paper constitutes the first successful experience of applying formal methods and satisfiability to quantum logic synthesis

Efficient Representation and Manipulation of Switching Functions Based on Ordered Kronecker Functional Decision Diagrams

An efficient package for construction of and operation on ordered Kronecker Functional Decision Diagrams (OKFDD) is presented. OKFDDs are a generalization of OBDDs and OFDDs and as such provide a more compact representation of the functions than either of the two decision diagrams. In this paper basic properties of OKFDDs and their efficient representation and manipulation are presented. Based on the comparison of the three decision diagrams for several benchmark functions, a 25% improve ment in size over OBDDs is observed for OKFDDs.

Decomposition of multiple-valued functions

This paper presents a generalized method for decomposition of multiple-valued functions. The main reason for using the described method is efficient implementation of logic circuits as well as effective representation of data in information systems. In logic synthesis, the method reduces the demand for silicon space required to implement designs. It is shown that the decomposition technique leads to additional compressing capabilities in PLA implementations. Another very promising area of application of decomposition is its effective representation of data in information systems, data bases and in other applications of information storing systems.

Minimization of exclusive sum-of-products expressions for multiple-valued input, incompletely specified functions

This paper presents a new operation (exorlink) and an algorithm to minimize Exclusive-OR Sum-of-Products expressions (ESOPs) for multiple valued input, two valued output, incompletely specified functions. Exorlink is a more powerful operation than any other existing one for this problem. Evaluation on benchmark functions is given and it proves the superiority of the program to those known from the literature.

Effective computer methods for the calculation of Rademacher-Walsh spectrum for completely and incompletely specified Boolean functions

A theory has been developed to calculate the Rademacher-Walsh transform from a cube array specification of incompletely specified Boolean functions. The importance of representing Boolean functions as arrays of disjoint ON- and DC-cubes has been pointed out, and an efficient new algorithm to generate disjoint cubes from nondisjoint ones has been designed. The transform algorithm makes use of the properties of an array of disjoint cubes and allows the determination of the spectral coefficients in an independent way. The programs for both algorithms use advantages of C language to speed up the execution. The comparison of different versions of the algorithm has been carried out. The algorithm and its implementation provide the fastest and most comprehensive program (having many options) known to the authors for the calculation of the Rademacher-Walsh transform. It successfully overcomes all drawbacks in the calculation of the transform from the design automation system based on spectral method-the SPECSYS system from Drexel University, which uses fast Walsh transform. >

Evolutionary Approach to Quantum andReversible Circuits Synthesis

The paper discusses theevolutionary computation approach to theproblem of optimal synthesis of Quantum andReversible Logic circuits. Our approach usesstandard Genetic Algorithm (GA) and itsrelative power as compared to previousapproaches comes from the encoding and theformulation of the cost and fitness functionsfor quantum circuits synthesis. We analyze newoperators and their role in synthesis andoptimization processes. Cost and fitnessfunctions for Reversible Circuit synthesis areintroduced as well as local optimizingtransformations. It is also shown that ourapproach can be used alternatively forsynthesis of either reversible or quantumcircuits without a major change in thealgorithm. Results are illustrated onsynthesized Margolus, Toffoli, Fredkin andother gates and Entanglement Circuits. This isfor the first time that several variants ofthese gates have been automatically synthesizedfrom quantum primitives.

Quantum logic synthesis by symbolic reachability analysis

Reversible quantum logic plays an important role in quantum computing. In this paper, we propose an approach to optimally synthesize quantum circuits by symbolic reachability analysis where the primary inputs are purely binary. we use symbolic reachability analysis, a technique most commonly used in model checking (a way of formal verification), to synthesize the optimum quantum circuits. We present an exact synthesis method with optimal quantum cost and a speedup method with non-optimal quantum cost. Both our methods guarantee the synthesizeability of all reversible circuits. Unlike previous works which use permutative reversible gates, we use a lower level library which includes non-permutative quantum gates. For the first time, problems in quantum logic synthesis have been reduced to those of multiple-valued logic synthesis thus reducing the search space and algorithm complexity. We synthesized quantum circuits for gate, half-adder, full-adder, etc. with the smallest cost.. Our approach obtains the minimum cost quantum circuits for Millers gate, half-adder, and full-adder, which are better than previous results. In addition, we prove the minimum quantum cost (using our elementary quantum gates) for Fredkin, Peres, and Toffoli gates. Our work constitutes the first successful experience of applying satisfiability with formal methods to quantum logic synthesis.

Fast exact and quasi-minimal minimization of highly testable fixed-polarity AND/XOR canonical networks

The authors introduce fast exact and quasi-minimal algorithms for minimal fixed polarity AND/XOR canonical representation of Boolean functions. The method uses features of arrays of disjoint cubes representations of functions to identify the minimal networks. These features can drastically reduce the search space and provide high quality heuristics for quasi-minimal representations. Experimental results show that these special AND/XOR networks, on the average, have a similar number of terms to Boolean AND/OR networks while there were functions for which AND/XOR circuits were much smaller. The circuits generated are much more testable.<<ETX>>

Evolving quantum circuits using genetic algorithm

In this paper we focus on a general approach of using genetic algorithm (GA) to evolve Quantum circuits (QC). We propose a generic GA to evolve arbitrary quantum. circuit specified by a (target) unitary matrix as well as a specific encoding that reduces the time of calculating the resultant unitary matrices of chromosomes. We demonstrate that, in contrast to previous approaches, our encoding allows synthesis of small quantum circuits of arbitrary type, using standard genetic operators.

Multi-output Galois Field Sum of Products synthesis with new quantum cascades

Galois Field Sum of Products (GFSOP) leads to efficient multi-valued reversible circuit synthesis using quantum gates. In this paper, we propose a new generalization of ternary Toffoli gate and another new generalized reversible ternary gale with discussion of their quantum realizations. Algorithms for synthesizing ternary GFSOP using quantum cascades of these gates are proposed In both the synthesis methods, 5 ternary shift operators and ternary swap gate are used We also propose quantum realizations of 5 ternary shift operators and ternary swap gate. In the cascades of the new ternary gates, local mirrors, variable ordering, and product ordering techniques are used to reduce the circuit cost. Experimental results show that the cascade of the new ternary gates is more efficient than the cascade of ternary Toffoli gates.