Related papers: Optical multi-qubit gate operations on an excitati…
In recent years, quantum state engineering and quantum information processing using microwave fields and photons have received increasing attention. In addition, multiqubit gates play an important role in quantum information processing. In…
We propose a scheme for realizing two-qubit quantum phase gates with two nonidentical quantum dots trapped in two coupled photonic crystal cavities and driven by classical laser fields. During the gate operation, neither the cavity modes…
We analyze the nonlinear optical response of a six-level atomic system under a configuration of electromagnetically induced transparency. The giant fifth-order nonlinearity generated in such a system with a relatively large cross-phase…
The family of $n$-bit Toffoli gates, with the two-bit Toffoli gate as the figurehead, are of great interest in quantum information as they can be used as universal gates and in quantum error correction, among other things. We present a…
We demonstrate quantum entanglement of two trapped atomic ion qubits using a sequence of ultrafast laser pulses. Unlike previous demonstrations of entanglement mediated by the Coulomb interaction, this scheme does not require confinement to…
For certain {\it specific} (or {\it"magic"}) Lamb-Dicke (LD) parameters, Monroe {\it et al} showed [Phys. Rev. {\bf A 55}, R2489 (1997)] that a two-qubit quantum operation, between the external and internal degrees of freedom of a single…
We propose a way to realize a multiqubit controlled phase gate with one qubit simultaneously controlling $n$ target qubits using atoms in cavity QED. In this proposal, there is no need of using classical pulses during the entire gate…
The circuit model of a quantum computer consists of sequences of gate operations between quantum bits (qubits), drawn from a universal family of discrete operations. The ability to execute parallel entangling quantum gates offers clear…
We show how to construct a multi-qubit control gate on a quantum register of an arbitrary size N. This gate performs a single-qubit operation on a specific qubit conditioned by the state of other N-1 qubits. We provide an algorithm how to…
Several sequential operations are usually needed for implementing controlled quantum gates and generating entanglement between a pair of quantum bits. Based on the conditional quantum dynamics for a two-ion system beyond the Lamb-Dicke…
We propose a single-step implementation of a muti-target-qubit controlled phase gate with one cat-state qubit (\textit{cqubit}) simultaneously controlling $n-1$ target \textit{cqubits}. The two logic states of a \textit{cqubit} are…
Fewer-qubit quantum logic gate, serving as a basic unit for constructing universal multiqubit gates, has been widely applied in quantum computing and quantum information. However, traditional constructions for fewer-qubit gates often…
We propose a fast optically induced two-qubit \textsc{c-phase} gate between two resident spins in a pair of coupled quantum dots. An excited bound state which extends over the two dots provides an effective electron-electron exchange…
We study the achievements of quantum circuits comprised of several one- and two-qubit gates. Quantum process matrices are determined for the basic one- and two-qubit gate operations and concatenated to yield the process matrix of the…
We propose a pulsed dynamical decoupling protocol as the generator of tunable, fast, and robust quantum phase gates between two microwave-driven trapped ion hyperfine qubits. The protocol consists of sequences of $\pi$-pulses acting on ions…
We describe a simple protocol for the single-step generation of $N$-body entangling interactions between trapped atomic ion qubits. We show that qubit state-dependent squeezing operations and displacement forces on the collective atomic…
We propose a scheme for realizing a two-qubit controlled phase gate via an unconventional geometric phase with two nonresonant quantum dots trapped in a photonic crystal cavity. In this system, the quantum dots simultaneously interact with…
Robust qubit-qubit interactions mediated by bosonic modes are central to many quantum technologies. Existing proposals combining fast oscillator-mediated gates with dynamical decoupling require strong pulses or fast control over the…
We present a scheme to realize multiple-qubit quantum state transfer and quantum logic gate by combining the advantages of Vitanov-style pulses and dressed-state-based shortcut to adiabaticity (STA) in Rydberg atoms. The robustness of the…
Applications for noisy intermediate-scale quantum computing devices rely on the efficient entanglement of many qubits to reach a potential quantum advantage. Although entanglement is typically generated using two-qubit gates, direct control…