Realization of the quantum Toffoli gate based on a six-level atomic system

In this paper, we propose a scheme for implementing a Toffoli gate in a system with an atom that has six levels in a lambda configuration, interacting with a high-Q cavity containing four modes. Here, we reduce a six-level system into an effective three-level behavior by applying the adiabatic elimination method. Next, we calculate the probabilities of the states of the interest as well as the fidelity. We also study the effects of photonic and atomic decay rates on the evolution of the system which is reasonably less sensitive to decoherence.

All-optical frequency-encoded Toffoli gate

The construction of an all-optical frequency-encoded Toffoli gate employing a reflecting semiconductor optical amplifier (RSOA) is proposed in this article. By establishing fields such as quantum computing, optical quantum computing, quantum-dot cellular automata, and superconducting flux logic family, quantum gates have been proved to perform reliably in the present day. A nonzero-mass electron, on the other hand, moves far slower than a quantum particle with zero rest mass, such as a photon. Photons can also be utilized to store data while being sent. These photon qualities have motivated researchers to create quantum gates in the all-optical domain based on them. The RSOA-based implementation of the Toffoli gate gives a significant improvement in the case of high speed, low power, and fast switching time. MATLAB Simulink (R2018a) software is used to simulate the devised design. The theoretical prediction is satisfied by the simulation results.

A general protocol for distributed quantum gates

In distributed quantum computation, quantum remote-controlled gates are used frequently and applied on separate nodes or subsystems of a network. One of the universal and well-known controlled gates is the n-qubit controlled-NOT gate, especially Toffoli gate for the case of three qubits, which are frequently used to synthesize quantum circuits. In this paper, we considered a more general case, an n-qubit controlled-U gate, and present a general protocol for implementing these gates remotely with minimum required resources. Then, the proposed method is applied to implement a Toffoli gate in bipartite and tripartite systems. In this method, we considered cases in which a group of qubits belongs to one subsystem of the network. Then, we improved its consumption resources.

Optimal energy estimation of Toffoli and Peres gate design using quantum-dot cellular automata

Quantum-dot cellular automata (QCA) are a novel dominant transistor-less computational nanotechnology. It is an appropriate candidate for the upcoming generation of quantum computational nano-electronics technology. The main objective of this research work is to present a QCA reversible logic circuits design such as the Toffoli gate (TG) and Peres gate (PG) and do the analysis of different parameters. In this paper, we propose a single layer coplanar method to solve this physical layout design and synchronization problem. The presented reversible logic gate (RLG) layout designs are implemented by Bijection functional algorithm for reduction of the number of QCA (quantum) cells, latency, and minimum design area. Also, the Optimized energy dissipation and effect of temperature on output polarization cell, of the proposed structure have been checked successfully using the tool QD-E (Energy) tool. The proposed QCA design has been verified by QCADesigner-E 2.2 tool using a bistable approximation and coherence vector engine. Finally, comparisons have been proposed RLG-TG and RLG-PG designs with the existing QCA design.