Realization of the Quantum Toffoli Gate with Trapped Ions

Abstract

Gates acting on more than two qubits are appealing as they can substitute complex sequences of two-qubit gates, thus promising faster execution and higher fidelity. One important multiqubit operation is the quantum Toffoli gate that performs a controlled NOT operation on a target qubit depending on the state of two control qubits. Here we present the first experimental realization of the quantum Toffoli gate in an ion trap quantum computer, achieving a mean gate fidelity of 71(3)%. Our implementation is particularly efficient as the relevant logic information is directly encoded in the motion of the ion string.

Efficient tomography of quantum-optical Gaussian processes probed with a few coherent states

“…These include the estimation of quantumoptical gates [8,11,[13][14][15][16][17][18][19], liquid nuclear-magneticresonance gates [20][21][22], superconducting gates [23][24][25][26][27][28] (for a review see Ref. [29]) and other solid-state gates [30][31][32], ion-trap gates [33,34], or the estimation of the dynamics of atoms in optical lattices [35]. In contrast, there are only a very few experimental demonstrations of QPT for infinite-dimensional systems (see, e.g., Ref.…”

Versatile ytterbium ion trap experiment for operation of scalable ion-trap chips with motional heating and transition-frequency measurements

“…Their suitability has been well demonstrated with state preparation and detection [13][14][15][16][17]; qubit entanglement, gates, and error correction [18][19][20][21][22][23][24][25][26][27]; and transport of ions within ion trap arrays [28][29][30][31][32][33][34][35][36]. Development of scalable traps that can encompass all of these operations is now the next stage toward more practical systems incorporating microfabricated chip traps [36][37][38][39][40][41][42][43][44][45][46][47], but realizing experimental setups can be challenging.…”

Five two-qubit gates are necessary for implementing the Toffoli gate

“…Recently, experimental implementation of the Toffoli gate has received considerable attention. The first experimental realization of the quantum Toffoli gate was presented in an ion-trap quantum computer, in 2009 at the University of Innsbruck, Austria [20]. Then, the Toffoli gate was realized in linear optics [21] and superconducting circuits [22,31,32].…”

“…Indeed, a study of the minimum cost of two-qubit gates for simulating a multiqubit gate is not only of theoretical importance, but also an experimental requirement: to accomplish a quantum algorithm, even at a small size, one has to implement a relatively high level of control over the multiqubit quantum system. A lot of experiments demonstrate multiqubit controlled-NOT gates in ion traps [20], linear optics [21], superconductors [22], and atoms [23].…”

“…Indeed, a study of the minimum cost of two-qubit gates for simulating a multiqubit gate is not only of theoretical importance, but also an experimental requirement: to accomplish a quantum algorithm, even at a small size, one has to implement a relatively high level of control over the multiqubit quantum system. A lot of experiments demonstrate multiqubit controlled-NOT gates in ion traps [20] Making controlled unitaries is an essential task for many algorithms in quantum computing [1]. Among all quantum controlled gates, those highly controlled unitaries (i.e., unitaries controlled on more than one other qubit) are useful in numerous quantum algorithms including the oracle in the * nengkunyu@gmail.com binary welded tree algorithm [5] and quantum simulation [24].…”