Читать книгу Quantum Computing - Hafiz Md. Hasan Babu - Страница 11

Quantum computing is a technology which consumes less power and for which the design is compact. In irreversible logic, energy dissipation is a common phenomenon since every bit loss causes energy loss in the irreversible operation. Quantum logic circuits are necessarily reversible and hence there is no dissipation of energy while processing a bit in quantum computation.

Quantum technology is one of the most promising nanotechnologies which are useful for designing modern circuits. Logic design with quantum logic is of great interest in recent technologies which allow scaling to atomistic dimensions. In this particular logic design approach, quantum cells are arranged in a particular fashion to define the logic. A classical gate cannot handle the superposition of states represented by a qubit (discussed in section 2.1 of chapter 2). Thus, this forms a special case of quantum device.

Quantum registers, which are necessary for the implementation of a quantum electronics device, combine n qubits to form larger Hilbert spaces H_n using the tensor product (⊗) operator to form

∣Ψ⟩=∣Ψ1⟩⊗∣Ψ2⟩⊗⋯⊗∣Ψn⟩=∑i=0n∣αi∣i⟩;

where αi∈C,∣Ψi〉 represents a qubit and ∑i=0n∣αi∣2=1. High-speed multiplication has always been a fundamental requirement of high-performance processors and systems. In quantum signal processing (QSP) applications, multiplication is one of the most utilized arithmetic operations. Improving multiplier design directly benefits the high-performance embedded processors and QSP applications used in consumer and industrial electronic products. Moreover, quantum information processing (QIP) is a high-impact research area in quantum information science to construct a quantum computer. The main goal of QIP is to harness the fundamental laws of quantum mechanics to dramatically improve all aspects (e.g. acquisition, transmission, and processing) of information processing as well as enhance the performance of quantum computers.

There are several tasks for which a quantum computer will be useful. The first, which is mentioned most frequently, is that quantum computers will be able to read secret messages communicated over the Internet using current technologies such as Rivest–Shamir–Adleman (RSA), Diffie–Hellman, and other cryptographic protocols; these protocols are based on the difficulty of number theoretic problems such as factoring and discrete logarithms. In addition, quantum computers are useful for scientists conducting virtual experiments and searching huge amounts of data.