Contents
How is computation performed in a quantum circuit?
The quantum circuit is a quantum computation model where computation is performed through a quantum gate sequence. Quantum gates are reversible, such as the inverter (NOT) gate, the output of which can be undone, and thus the input data can be obtained from the output data. Quantum gates are used for the updating of qubits to obtain a better
How are quantum gates used in a circuit?
In all descriptions of quantum circuits in addition to gates, we see quantum wires that move qubits and allow us to compose more complex circuits from simpler ones that, in turn, are composed of quantum gates.
How are quantum circuits similar to classical computers?
Quantum circuits are the most straightforward analogue of classical computers: wires connect gates which manipulate qubits. The transformation made by the gates is always reversible: this is a remarkable departure from classical computers. The circuit description uses simple diagrams to represent connections.
How is a quantum circuit similar to a Turing machine?
Yao [ 218] showed that a quantum circuit model is equivalent to a quantum Turing machine in the sense that they can simulate each other in polynomial time. The relationship between programs and Turing machines is well understood; see for example [ 41, 127 ].
How is a quantum circuit related to a n qubit register?
In quantum information theory, a quantum circuit is a model for quantum computation in which a computation is a sequence of quantum gates, which are reversible transformations on a quantum mechanical analog of an n-bit register. This analogous structure is referred to as an n-qubit register.
Can a quantum circuit produce a reversible circuit?
For quantum circuits a similar composition of qubit gates can be defined. That is, associated to any classical assemblage as above, we can produce a reversible quantum circuit when in place of f we have an n -qubit gate U and in place of g we have an m -qubit gate W. See illustration below:
Which is an analogy for a quantum circuit?
In quantum information theory, a quantum circuit is a model for quantum computation in which a computation is a sequence of quantum gates, which are reversible transformations on a quantum mechanical analog of an n-bit register. This analogous structure is referred to as an n-qubit register. 1 Reversible classical logic gates.
Which is an example of an operator in quantum mechanics?
We will now introduce three additional postulates: Each observable in classical mechanics has an associated operator in quantum mechanics. Examples of observables are position, momentum, kinetic energy, total energy, angular momentum, etc (Table 11.3. 1 ).
How is the evolution of a quantum circuit governed?
It is a continuous-time model of quantum computation in which the evolution of the quantum register is governed by a Hamiltonian that varies slowly. The state of the system is prepared at the beginning in the ground state of the initial Hamiltonian.
What are the different models of quantum computing?
Quantum computing has several operational models, but only two are crucial for later chapters: quantum circuits and adiabatic quantum computing. Other models include topological quantum computing and one-way quantum computing. We begin with a discussion of quantum circuits.
Is the complexity of compiling a quantum circuit relevant to Qiskit?
Our theoretical results on the complexity of the quantum circuit compilation problem are very relevant to Qiskit. More specifically, Qiskit Terra provides the foundation of the quantum software stack to optimize the quantum circuits for a particular physical quantum device.