In this paper we present novel ultra-low-voltage and high-speed CMOS NAND and NOR gates. For supply voltages below 500mV the delay for an ultra-low-voltage NAND2 gate is approximately 10% of a complementary CMOS inverter. Furthermore, the delay variations due to mismatch are much lesser than for conventional CMOS. Differential domino gates for AND2/NAND2 and OR2/NOR2 operation are presented. Ul...

Reversible logic plays an important role in quantum computing. Several papers have been recently published on universality of sets of reversible gates. However, a fundamental unsolved problem remains: “what is the minimum set of gates that are universal for n-qubit circuits without ancillae bits”. We present a library of 2 gates which is sufficient to realize all reversible circuits of n variab...

Usually models for quantum computations deal with unitary gates on pure states. In this paper we generalize the usual model. We consider a model of quantum computations in which the state is an operator of density matrix and the gates are quantum operations, not necessarily unitary. A mixed state (operator of density matrix) of n two-level quantum systems is considered as an element of 4n-dimen...

The paper deals with the problem of designing digital circuits with the currentmode gates novel digital gates operating with constant, continuous power supply current. The purpose is the provision of a high level of noise immunity of the chips which compose both analog and digital circuits. The logical properties of the current-mode gates and logic (algebra) are investigated, which are a base t...

In recent past, reversible logic is emerged as a promising computing paradigm with applications in low-power CMOS, quantum computing, optical computing and nanotechnology. Optical logic gates become potential component to work at macroscopic (light pulses carry information), or quantum (single photon carries information) levels with high efficiency. In this paper, we propose a novel scheme of T...

New techniques for reducing the depth of circuits for cryptographic applications are described. These techniques also keep the number of gates quite small. The result, when applied to the AES S-Box, is a circuit with depth 16 and only 128 gates. For the inverse, it is also depth 16 and has only 127 gates. There is a shared middle part, common to both the S-Box and its inverse, consisting of 63 ...

We investigate the possibility of realizing effective quantum gates between two atoms in distant cavities coupled by an optical fiber. We show that highly reliable swap and entangling gates are achievable. We exactly study the stability of these gates in the presence of imperfections in coupling strengths and interaction times and prove them to be robust. Moreover, we analyze the effect of spon...

A variant of Kauffman's model of cellular metabolism is presented. It is a randomly generated network of boolean gates, identical to Kauffman's except for a small bias in favor of boolean gates that depend on at most one input. The bias is asymptotic to 0 as the number of gates increases. Upper bounds on the time until the network reaches a state cycle and the size of the state cycle, as functi...

Polymorphic gates are unconventional circuit components that are not supported by existing synthesis tools. This article presents new methods for synthesis of polymorphic circuits. Proposed methods, based on polymorphic binary decision diagrams and polymorphic multiplexing, extend the ordinary circuit representations with the aim of including polymorphic gates. In order to reduce the number of ...

A quantum circuit is generalized to a nonunitary one whose constituents are nonunitary gates operated by quantum measurement. It is shown that a specific type of one-qubit nonunitary gates, the controlled-not gate, as well as all one-qubit unitary gates constitute a universal set of gates for the nonunitary quantum circuit, without the necessity of introducing ancilla qubits. A reversing measur...