Refined Deutsch-Jozsa Algorithm Research Articles

Implementation of Quantum Algorithms via Fast Three-Rydberg-Atom CCZ Gates

Multiqubit CCZ gates form one of the building blocks of quantum algorithms and have been involved in achieving many theoretical and experimental triumphs. Designing a simple and efficient multiqubit gate for quantum algorithms is still by no means trivial as the number of qubits increases. Here, by virtue of the Rydberg blockade effect, we propose a scheme to rapidly implement a three-Rydberg-atom CCZ gate via a single Rydberg pulse, and successfully apply the gate to realize the three-qubit refined Deutsch–Jozsa algorithm and three-qubit Grover search. The logical states of the three-qubit gate are encoded to the same ground states to avoid an adverse effect of the atomic spontaneous emission. Furthermore, there is no requirement for individual addressing of atoms in our protocol.

Electric field manipulation enhanced by strong spin-orbit coupling: promoting rare-earth ions as qubits.

Quantum information processing based on magnetic ions has potential for applications as the ions can be modified in their electronic properties and assembled by a variety of chemical methods. For these systems to achieve individual spin addressability and high energy efficiency, we exploited the electric field as a tool to manipulate the quantum behaviours of the rare-earth ion which has strong spin-orbit coupling. A Ce:YAG single crystal was employed with considerations to the dynamics and the symmetry requirements. The Stark effect of the Ce3+ ion was observed and measured. When demonstrated as a quantum phase gate, the electric field manipulation exhibited high efficiency which allowed up to 57 π/2 operations before decoherence with optimized field direction. It was also utilized to carry out quantum bang-bang control, as a method of dynamic decoupling, and the refined Deutsch-Jozsa algorithm. Our experiments highlighted rare-earth ions as potentially applicable qubits because they offer enhanced spin-electric coupling which enables high-efficiency quantum manipulation.

Non-Markovianity-assisted high-fidelity Deutsch\u2013Jozsa algorithm in diamond

The memory effects in non-Markovian quantum dynamics can induce the revival of quantum coherence, which is believed to provide important physical resources for quantum information processing (QIP). However, no real quantum algorithms have been demonstrated with the help of such memory effects. Here, we experimentally implemented a non-Markovianity-assisted high-fidelity refined Deutsch–Jozsa algorithm (RDJA) with a solid spin in diamond. The memory effects can induce pronounced non-monotonic variations in the RDJA results, which were confirmed to follow a non-Markovian quantum process by measuring the non-Markovianity of the spin system. By applying the memory effects as physical resources with the assistance of dynamical decoupling, the probability of success of RDJA was elevated above 97% in the open quantum system. This study not only demonstrates that the non-Markovianity is an important physical resource but also presents a feasible way to employ this physical resource. It will stimulate the application of the memory effects in non-Markovian quantum dynamics to improve the performance of practical QIP.

Implementation of refined Deutsch–Jozsa algorithm in a superconducting qutrit system

AbstractSuperconducting quantum circuits are promising candidates for realizing quantum computation due to their intrinsic scalability. Here, we report the implementation of the refined Deutsch–Jozsa algorithm in a 3D superconducting transmon qutrit system. Such 3D superconducting systems usually preserve a relatively long coherence time. A qutrit can take advantage of the third level of a superconducting artificial atom and extends the Hilbert space. Compared with the two‐qubit system used for realizing Deutsch–Jozsa algorithm, the employment of qutrit simplifies the hardware design. This simplification and the intrinsic long coherence time jointly lead to a higher fidelity than in previous transmon implementation [DiCarlo et al., Nature 460 (7252), 240–244 (2009)].

Circuit QED: implementation of the three-qubit refined Deutsch–Jozsa quantum algorithm

We propose a protocol to construct the 35 $$f$$f-controlled phase gates of a three-qubit refined Deutsch---Jozsa (DJ) algorithm, by using single-qubit $$\sigma _z$$?z gates, two-qubit controlled phase gates, and two-target-qubit controlled phase gates. Using this protocol, we discuss how to implement the three-qubit refined DJ algorithm with superconducting transmon qutrits resonantly coupled to a single cavity. Our numerical calculation shows that implementation of this quantum algorithm is feasible within the present circuit QED technique. The experimental realization of this algorithm would be an important step toward more complex quantum computation in circuit QED.

Cavity QED implementation of the multi-qubit refined Deutsch–Jozsa algorithm

We theoretically study the realization of a multi-qubit refined Deutsch–Jozsa (DJ) algorithm using resonant interaction of many Rydberg atoms with a single-mode microwave cavity, in which the multi-qubit controlled phase gates could be accomplished efficiently. We show how to achieve a multi-qubit refined DJ algorithm in high fidelity, even in the case of a weak cavity decay and some imperfection. We argue that the required operations in our scheme are almost within the present experimental possibilities.

Quantum Logic Circuits and Optical Signal Generation for a Three-Qubit, Optically Controlled, Solid-State Quantum Computer

We analyze the preparation of an experimental demonstration for a three-qubit, optically controlled, solid-state quantum computational system. First, using a genetic programming approach, we design quantum logic circuits, specifically tailored for our computational model, which implement a three-qubit refined Deutsch-Jozsa algorithm. Aiming at achieving the shortest possible computational time, we compare two design strategies based on exploiting two different sets of entangling gates. The first set comprises fast approximations of controlled-phase gates, while in the second case, we exploit arbitrary entangling gates with gate computational times shorter than those of the first set. Then, considering some recently proposed material implementations of this quantum computational system, we discuss the generation of the near-midinfrared, multiwavelength and picosecond optical pulse sequences necessary for controlling the presented quantum logic circuits. Finally, we analyze potential sources of errors and assess the impact of random fluctuations of the parameters controlling the entangling gates on the overall quantum computational system performance.

Scheme for Implementing Refined Deutsch–Jozsa Algorithm via Superconducing Qubits

We propose a scheme of implementing the Deutsch–Jozsa algorithm based on superconducing charge qubits, which would be a key step to scale more complex quantum algorithms and very important for constructing a real quantum computer via superconducting charge qubits. The present scheme is simple but fairly efficient, and easily manipulated because arbitrary two-qubit can be selectively and effectively coupled by a common inductance. More manipulations can be carried out before decoherence sets in. The proposed scheme is in line with current technology.

Implementation of a three-qubit refined Deutsch–Jozsa algorithm using SFG quantum logicgates

In this paper we present a quantum logic circuit which can be used for the experimentaldemonstration of a three-qubit solid state quantum computer based on a recent proposal ofoptically driven quantum logic gates. In these gates, the entanglement of randomly placedelectron spin qubits is manipulated by optical excitation of control electrons. The circuit wedescribe solves the Deutsch problem with an improved algorithm called the refinedDeutsch–Jozsa algorithm. We show that it is possible to select optical pulses that solve theDeutsch problem correctly, and do so without losing quantum information to the controlelectrons, even though the gate parameters vary substantially from one gate to another.

Implementation of the refined Deutsch-Jozsa algorithm on a three-bit NMR quantum computer

We implemented the refined Deutsch-Jozsa algorithm on a 3-bit nuclear magnetic resonance quantum computer, which is the meaningful test of quantum parallelism because qubits are entangled. All of the balanced and constant functions were realized exactly. The results agree well with theoretical predictions and clearly distinguish the balanced functions from constant functions. Efficient refocusing schemes were proposed for the soft z-pulse and J-coupling and it is proved that the thermal equilibrium state gives the same results as the pure state for this algorithm.