États de Bell

Résumé

Les états de Bell sont en informatique quantique les états d'intrication maximale de deux particules. Description Les quatre états ci-dessous à deux qubits, correspondant à une intrication maximale, sont désignés comme étant les États de Bell : :|\Phi^+\rangle = \frac{1}{\sqrt{2}} (|0\rangle_A \otimes |0\rangle_B + |1\rangle_A \otimes |1\rangle_B) (1) :|\Phi^-\rangle = \frac{1}{\sqrt{2}} (|0\rangle_A \otimes |0\rangle_B - |1\rangle_A \otimes |1\rangle_B) (2) :|\Psi^+\rangle = \frac{1}{\sqrt{2}} (|0\rangle_A \otimes |1\rangle_B + |1\rangle_A \otimes |0\rangle_B) (3) :|\Psi^-\rangle = \frac{1}{\sqrt{2}} (|0\rangle_A \otimes |1\rangle_B - |1\rangle_A \otimes |0\rangle_B) (4) Obtention vignette|Circuit quantique obtenant |\Phi^+\rangle. Un circuit quantique composé d'une porte de Hadamard et d'une permet d'obtenir le premier état de Bell |\Phi^+\rangle. Ce circuit

Source officielle

https://fr.wikipedia.org/wiki/%C3%89tats_de_Bell

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (4)

Publications associées

Chargement

Personnes associées

Chargement

Unités associées

Chargement

Concepts associés (20)

Concepts associés

Chargement

Cours associés (7)

Cours associés

Chargement

Séances de cours associées (13)

Séances de cours associées

Chargement

, ,

We present a method for the exact diagonalization of the SU(N) Heisenberg interaction Hamiltonian using Young tableaus to work directly in each irreducible representation of the global SU(N) group. This generalized scheme is applicable to chains consisting of several particles per site, with any SU(N) symmetry at each site. Extending some of the key results of substitutional analysis, we demonstrate how basis states can be efficiently constructed for the relevant SU(N) subsector, which, especially with increasing values of N or numbers of sites, has a much smaller dimension than the full Hilbert space. This allows us to analyze systems of larger sizes than can be handled by existing techniques. We apply this method to investigate the presence of edge states in SU(N) Heisenberg and Affleck-Kennedy-Lieb-Tasaki Hamiltonians.

2017

Chargement

Semiconductor qubits rely on the control of charge and spin degrees of freedom of electrons or holes confined in quantum dots (QDs). Typically, semiconductor qubit-qubit coupling is short range, effectively limiting qubit distance to the spatial extent of the wavefunction of the confined particle (a few hundred nanometers). This is a significant constraint towards scaling of QD-based architectures to realize dense 1D or 2D arrays of QDs. Inspired by techniques originally developed for circuit QED, we recently demonstrated the strong coupling of individual electrons confined in GaAs quantum dots to individual microwave photons, making use of the enhanced electric component of the vacuum fluctuations of a resonator with impedance beyond the typical 50 Ohm of standard coplanar waveguides. In this hybrid technology, we recently realized a proof of concept experiment, where the coupling between a transmon and a double QD (DQD) is mediated by virtual microwave photon excitations in a high impedance SQUID array resonator, which acts as a quantum bus enabling long-range coupling between dissimilar qubits. Similarly, we achieved coherent coupling between two DQD charge qubits separated by approximately 50 um. In the dispersive regime, we spectroscopically observed qubit-qubit coupling as an avoided-crossing in the energy spectrum of the DQD charge qubits. The methods and techniques developed in this work are transferable to QD devices based on other material systems and can be beneficial for spin based hybrid systems.

2019

Chargement

Automatic Uniform Quantum State Preparation Using Decision Diagrams

Giovanni De Micheli, Fereshte Mozafari Ghoraba, Heinz Riener, Mathias Soeken

Most quantum algorithms assume some specific initial state in superposition of basis states before performing the desired application-specific computations. The preparation of such states itself requires a computation performed by a quantum circuit. In this paper, we investigate the automatic state preparation of a specific subset of quantum states that are uniform superpositions over a subset of basis states, called uniform quantum states. We exploit that such states can be represented using Boolean functions and present a recursive algorithm based on functional decomposition. When using binary decision diagrams as function representation, we can enable fast and scalable quantum state preparation with respect to the size of the decision diagram. We show that the algorithm can find quantum circuits for functions, where state-of-the-art algorithms cannot be applied anymore.

2020

Chargement