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Quantum Information Processes
Published in Thiruselvan Subramanian, Archana Dhyani, Adarsh Kumar, Sukhpal Singh Gill, Artificial Intelligence, Machine Learning and Blockchain in Quantum Satellite, Drone and Network, 2023
B.S. Tewari, P. Mandal, Prashant Rawat
The working of a quantum computer is based on quantum information processes and manipulation [28]. After the understanding of memory units of a quantum computer, the next significant point of understanding is the computation methodology of quantum computers, i.e., the manner and type of operations that can be performed to solve problems using the concept of quantum mechanics. The quantum logic gates manipulate quantum information and perform operations that transform qubit states. Hence, the understanding of logic operations is an important task to understand the working of a quantum computer. Quantum logic gates are classified into two categories based on the number of qubit operations. Single qubit quantum gates operate with a single qubit, whereas multiple qubit quantum gates work with more than one qubits. One of the most essential characteristics of quantum gates is that they must be invertible, which means that we can know the input once we get the output. Matrixes are used to represent quantum gates. The matrix U that describes the gates must be unitary, that is, it must meet the following conditions: U+U=I
CMOS Circuits
Published in Michael Olorunfunmi Kolawole, Electronics, 2020
As the degree of integration increases, more components are integrated on a chip and more wires are necessary to interconnect them. As a result, more power would be consumed on on-chip interconnections, which could impair the performance of the chip. Efforts are being made by innovative technology to lower power consumption, reduce latency, and improve performance on-chip network. Some examples of this innovative technology include “quantum logic gate” in silicon [15], the use of silicon photonics—the application of photonic systems with silicon as the optical medium [14], graphene [16], and CNTs [13]. A quantum logic gate (or simply quantum gate) is a basic quantum circuit operating on a small number of qubits. Traditionally, bits are either 1 or 0, while in a quantum gate; qubits can be both numbers at the same time. Quantum logic gates are reversible, unlike many classical (traditional) logic gates. (More is said about quantum gates and electronics in Chapter 9.)
Physically Defined Coupled Silicon Quantum Dots Containing a Few Electrons for Electron Spin Qubits
Published in Simon Deleonibus, Emerging Devices for Low-Power and High-Performance Nanosystems, 2018
Tetsuo Kodera, Kosuke Horibe, Shunri Oda
A bit in quantum computing, termed a “quantum bit” (qubit), is realized by the superposition of two-level quantum states. Quantum computing requires two well-defined and controllable states to qualify a qubit, which possesses the stability and ability to construct a quantum logic gate. So far, various two-level systems have been investigated theoretically and experimentally to build qubits, such as NMR on molecules in solution [2], trapped ions, and linear optical quantum effects [17]. However, for the purpose of large-scale integration, qubits based on solid-state quantum systems are more promising. In particular, charges or spins of electrons, confined in semiconductor QDs, have attracted attention as candidate state variables for defining qubits.
Atomic swap gate, driven by position fluctuations, in dispersive cavity optomechanics
Published in Journal of Modern Optics, 2019
Anil Kumar Chauhan, Asoka Biswas
Quantum logic gate is one of the key elements in a quantum computer. The two-qubit gates along with a few single-qubit operations make the necessary building block in quantum computing. Such gates have been extensively studied and implemented in several physical systems, e.g. cavity quantum electrodynamics (QED) (1), trapped ion (2), nuclear magnetic resonance (3), and superconducting Cooper pairs (4). An array of qubits (like in spin chain) also poses as a suitable platform for scalable quantum computing (5), while linear optical system based on single photons has been found to be suitable for quantum communication over a long distance (6).