Quantum cellular automata

Abstract

We formulate a new paradigm for computing with cellular automata (CAS) composed of arrays of quantum devices-quantum cellular automata. Computing in such a paradigm is edge driven. Input, output, and power are delivered at the edge of the cnarray only; no direct flow of information or energy to internal cells is required. Computing in this paradigm is also computing with the ground state. The architecture is so designed that the ground-state configuration of the array, subject to boundary conditions determined by the input, yields the computational result. We propose a specific realization of these ideas using two-electron cells composed of quantum dots, which is within the reach of current fabrication technology. The charge density in the cell is very highly polarized (aligned) along one of the two cell axes, suggestive of a twostate CA. The polarization of one cell induces a polarization in a neighboring cell through the Coulomb interaction i n a very non-linear fashion. Quantum cellular automata can perform useful computing. We show that AND gates, OR gates, and inverters can be constructed and interconnected.

The ternary quantum-dot cell and ternary logic

“…As already discussed, the QCA structures are capable of both processing and data transfer, but what about data storage? In their seminal paper, Lent et al [3] stated that a single quantum-dot cell can act as a data storage cell, since a cell, whose electrons have stabilised in a certain arrangement, will in principle remain in that configuration indefinitely. The latter can be interpreted as data preservation.…”

“…It was set up by C.S. Lent [3,4] at the start of the last decade as a planar structure comprised of cells, each containing a set of four quantum-dots separated by tunnelling barriers and occupied by two electrons. According to Lent, each cell can be in one of two distinct states, distinguishable by means of the arrangement of the electrons.…”

“…According to Lent, each cell can be in one of two distinct states, distinguishable by means of the arrangement of the electrons. The growing interest in QCAs in the last decade resulted in the development of QCA structures that implement the functionally complete set of binary logic functions {AND, OR, NOT} [3,4,5], as well as the development of tools that enable the design and simulation of more complex QCA structures [6]. The primary drawback of QCAs, however, is ironically the bi-stability of the comprising cells.…”

Digital Combinational Circuits Design with the Help of Symmetric Functions Considering Heat Dissipation by Each QCA Gate

“…Reversible Quantum Computers (QCs) has drawn the attention of researchers recently as such computers result improvement in speed, reducing cost and space etc [1]- [6], [11]- [18]. Reversible gates and circuits are the main components of Quantum Computer.…”

“…imposing no restriction of the variable form, e. g. X 1 ' X 2 'X 3 + X 1 X 2 'X 3 ' + X 1 'X 2 X 3 ' II. QUANTUM DOT CELLULAR AUTOMATA QCA (Quantum-dot Cellular Automata) [1]- [18] devices encode and process binary information as charged arrays of charge coupled quantum dots. A quantum cell can be viewed as a set of four charge containers or dots positioned at the corners of a square, as shown in Fig.…”