The More You Know: Quantum Circuit

Quantum Circuits are used to visualize a prescription of quantum gates acting on a quantum state. They describe the changes of the quantum data as it undergoes successive discrete operations.

The data in a Quantum Circuit is usually encoded in a n-qubit state (other Quantum Circuit models can use m-level quantum systems instead of these 2-level systems) which is set to a known vale, i.e. |000...\rangle. Thus, for every qubit in the circuit a horizontal rail, a wire, is drawn to represent its evolution, time flows from left to right.


Wires in a Quantum Circuit initialized to the n-qubit quantum state |000...\rangle.

Additionally, a Quantum Circuit is built from elementary quantum gates (unitary operations) acting on a fixed number of qubits. Since Quantum Circuits are read from left to right, leftmost gates act first.


Single-qubit and Two-qubit quantum gates in a Quantum Circuit.

Then, a description of the Quantum System consists of

  1. Input: A controlled input n-qubit state.
  2. Evolution: Prescribed sequence of Unitary Single-qubit and Two-qubit logic quantum gates which give the evolution of the initial quantum state.
  3. Output: Readout (measurement) of the state of the n qubits.

Go to the Dictionary of Quantum Information and Quantum Computation.


Quantum Circuits where drawn using this LaTeX package.

 All text copyright © Marco Vinicio Sebastian Cerezo de la Roca.

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The More You Know: Quantum Circuit por Marco Vinicio Sebastian Cerezo de la Roca se distribuye bajo una Licencia Creative Commons Atribución-NoComercial-CompartirIgual 4.0 Internacional.



About marcocerezo

My name is Marco Cerezo, I have a degree in physics from the Universidad Nacional de la Plata (UNLP) in Buenos Aires, Argentina, and I'm a Ph.D student. Although I study in Argentina, I was born and raised in Guatemala, so I consider myself "chapín" at heart. From an early age I discovered how exciting, interesting and fun physics can be, so I decided to devote myself to study this passionate field. This blog is dedicated to all those who want to dig a little into the mysteries and beauty of physics. And in particular, to all those who are interested in studying Quantum Computation and Quantum Information. ---------------------------------------------------------------------------------------------------------- Mi nombre es Marco Cerezo, Licenciado en Física egresado de la Universidad Nacional de la Plata (UNLP) en Buenos Aires, Argentina. Actualmente estoy haciendo mi Doctorado en física. Aunque estudio en Argentina, nací y crecí en Guatemala por lo que me considero chapín de corazón. Desde muy temprana edad descubrí lo apasionante, interesante y divertida que es la física por lo que decidí dedicarme a su estudio. Este blog es está dedicado a todos aquellos que quieren indagar un poco en los misterios y la belleza de la física; y en particular, a aquellos que quieran aprender sobre Computación e Información Cuántica.
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