Large-scale universal quantum computing requires the implementation of quantum error correction (QEC). While the implementation of QEC has already been demonstrated for quantum memories, reliable quantum computing requires also the application of nontrivial logical gate operations to the encoded qubits. Here, we present examples of such operations by implementing, in addition to the identity op...

The identification of an unknown quantum gate is a significant issue in quantum technology. In this paper, we propose a quantum gate identification method within the framework of quantum process tomography. In this method, a series of pure states are inputted to the gate and then a fast state tomography on the output states is performed and the data are used to reconstruct the quantum gate. Our...

quantum dot cellular automata (qca) is one of the important nano-level technologies for implementation of both combinational and sequential systems. qca have the potential to achieve low power dissipation and operate high speed at thz frequencies. however large probability of occurrence fabrication defects in qca, is a fundamental challenge to use this emerging technology. because of these vari...

The physical implementation of the quantum Control-Not gate for a two-spin system is investigated numerically. The concept of a generalized quantum Control-Not gate, with arbitrary phase shift, is introduced. It is shown that a resonant π-pulse provides a simple example of a generalized quantum Control-Not gate.

Trapped ions are a promising tool for building a large-scale quantum computer. However, the number of required radiation fields for the realization of quantum gates in any proposed ion-based architecture scales with the number of ions within the quantum computer, posing a major obstacle when imagining a device with millions of ions. Here, we present a fundamentally different approach for trappe...

A comprehensive study of Schottky barrier MOSFET (SBMOSFET) scaling issue is performed to determine the role of wafer orientation and structural parameters on the performance of this device within Non-equilibrium Green's Function formalism. Quantum confinement increases the effective Schottky barrier height (SBH). (100) orientation provides lower effective Schottky barrier height in compa...

The quantum circuit is generalized to include non-unitary gates operated by quantum measurement, in order to reduce the number of the overhead of qubits required to ensure fault tolerance. A specific type of one-qubit non-unitary gates, together with the controlled-not gate and all one-qubit unitary gates, is shown to constitute a universal set of gates for the non-unitary quantum circuit. A re...

The sum gate is the canonical two-mode gate for universal quantum computation based on continuous quantum variables. It represents the natural analogue to a qubit C-NOT gate. In addition, the continuous-variable gate describes a quantum nondemolition (QND) interaction between the quadrature components of two light modes. We experimentally demonstrate a QND sum gate, employing the scheme by R. F...

Quantum-dot cellular automaton (QCA) is a novel nanotechnology with a very different computational method in compared with CMOS, whereas placement of electrons in cells indicates digital information. This nanotechnology with specifications such as fast speed, high parallel processing, small area, low power consumption and higher switching frequency becomes a promising candidate for CMOS tec...