Quantum algorithm for linear systems of equationsThe quantum algorithm for linear systems of equations, also called HHL algorithm, designed by Aram Harrow, Avinatan Hassidim, and Seth Lloyd, is a quantum algorithm published in 2008 for solving linear systems. The algorithm estimates the result of a scalar measurement on the solution vector to a given linear system of equations. The algorithm is one of the main fundamental algorithms expected to provide a speedup over their classical counterparts, along with Shor's factoring algorithm, Grover's search algorithm, and the quantum fourier transform.
Ancilla bitIn reversible computing, ancilla bits are extra bits being used to implement irreversible logical operations. In classical computation, any memory bit can be turned on or off at will, requiring no prior knowledge or extra complexity. However, this is not the case in quantum computing or classical reversible computing. In these models of computing, all operations on computer memory must be reversible, and toggling a bit on or off would lose the information about the initial value of that bit.
Code quantiqueLes codes quantiques sont l'équivalent quantique des codes correcteurs. La théorie des codes quantiques est donc une branche de l'information quantique qui s'applique à protéger l'information quantique des effets de la décohérence. La correction d'erreur quantique est un élément essentiel du calcul tolérant aux fautes qui doit gérer non seulement les erreurs dans l'information stockée, mais aussi dans l'application des portes quantiques, la préparation de nouveaux états ainsi que dans les opérations de mesure.
Flux qubitIn quantum computing, more specifically in superconducting quantum computing, flux qubits (also known as persistent current qubits) are micrometer sized loops of superconducting metal that is interrupted by a number of Josephson junctions. These devices function as quantum bits. The flux qubit was first proposed by Terry P. Orlando et al. at MIT in 1999 and fabricated shortly thereafter. During fabrication, the Josephson junction parameters are engineered so that a persistent current will flow continuously when an external magnetic flux is applied.
Quantum programmingQuantum programming is the process of designing or assembling sequences of instructions, called quantum circuits, using gates, switches, and operators to manipulate a quantum system for a desired outcome or results of a given experiment. Quantum circuit algorithms can be implemented on integrated circuits, conducted with instrumentation, or written in a programming language for use with a quantum computer or a quantum processor. With quantum processor based systems, quantum programming languages help express quantum algorithms using high-level constructs.
Quantum counting algorithmQuantum counting algorithm is a quantum algorithm for efficiently counting the number of solutions for a given search problem. The algorithm is based on the quantum phase estimation algorithm and on Grover's search algorithm. Counting problems are common in diverse fields such as statistical estimation, statistical physics, networking, etc. As for quantum computing, the ability to perform quantum counting efficiently is needed in order to use Grover's search algorithm (because running Grover's search algorithm requires knowing how many solutions exist).
Quantum information scienceQuantum information science is a field that combines the principles of quantum mechanics with information science to study the processing, analysis, and transmission of information. It covers both theoretical and experimental aspects of quantum physics, including the limits of what can be achieved with quantum information. The term quantum information theory is sometimes used, but it does not include experimental research and can be confused with a subfield of quantum information science that deals with the processing of quantum information.
Simulateur quantiquevignette|Sur cette photo d'un simulateur quantique, les ions sont fluorescents, ce qui indique que les qubits sont tous dans le même état ("1" ou "0"). Dans de bonnes conditions expérimentales, les ions du cristal prennent spontanément une structure triangulaire. Crédit: Britton/NIST vignette|Illustration de ions piégés : Le cœur du simulateur est un cristal de deux dimensions de ions de béryllium (sphères bleues); l'électron ultrapériphériques de chaque ion est un bits quantiques (flèches rouges).
Algorithme d'estimation de phase quantiqueEn informatique quantique, l’algorithme d'estimation de phase quantique est un permettant d'estimer la valeur propre (ou sa phase, ce qui, dans ce cas précis, est équivalent) d'un opérateur unité associée à un vecteur propre donné. Les valeurs propres d'un opérateur unitaire U, agissant sur m bits, sont de module 1. Si est un vecteur propre de U, nous avons donc . Le but de cet algorithme est de trouver la valeur de la phase correspondant à un vecteur propre donné, ceci avec une précision de n bits (la phase n'a pas nécessairement une valeur exacte).
Trapped ion quantum computerA trapped ion quantum computer is one proposed approach to a large-scale quantum computer. Ions, or charged atomic particles, can be confined and suspended in free space using electromagnetic fields. Qubits are stored in stable electronic states of each ion, and quantum information can be transferred through the collective quantized motion of the ions in a shared trap (interacting through the Coulomb force).
